Special motives: Automotive Inventors and Alternative Fuels in the 1920s
Paper to a conference of the Society for the History of Technology, Washington D.C., Oct. 19, 2007
By Bill Kovarik, Ph.D.
The history of alternative fuels, especially ethanol (ethyl alcohol), is not well understood. Although a successful alternative fuels industry has emerged in recent years, it remains an area in need of historical research. This paper explores alternative fuels as they were seen by three key automotive inventors– Henry Ford, Charles Kettering (research head of General Motors) and Harry Ricardo (a British engineer). These three inventors anticipated the depletion of petroleum reserves within their lifetimes and considered ethanol as the best response in the context of their own motivations and world views.
Henry Ford hoped that widespread use of ethanol from farm products would strengthen rural economies. He backed a populist farming movement that continued through the 1960s. Charles Kettering and his staff at General Motors hoped to save the auto industry from an anticipated oil shortage. Kettering’s original special motive for developing tetraethyl lead was to allow higher compression engines that would be more efficient and more easily adapted to ethanol when oil ran out. British engineer Henry Ricardo, a leading engine designer, was concerned about Britain’s research efforts before and after World War I. Ricardo’s patented ‘Discol’ alcohol fuel formula was widely used for racing and became a popular consumer fuel in Britain from the 1930s through the 1960s.
All three automotive engineers were looking for a fuel that was not derived from coal or oil. They thought, along with most of their contemporaries, that ethanol would be the fuel of the future. In the first edition of his classic 1921 book on the internal combustion engine, Ricardo said it was an “absolute necessity to find an alternative fuel” and that alcohol was the most likely candidate.
But as the 1920s came to an end, and fears of an immediate oil crisis proved unwarranted, the original special motives for the development of alternative fuels systems became economically and politically problematic. Subsequent editions of Ricardo’s book contained no optimistic note about alternative fuels; the idea of moving from leaded gasoline to alcohol was abandoned at GM; and Henry Ford found a broader context for his agrarianism in soybean-based plastics and other industrial uses of farm products.
Keywords: ethanol, ethyl alcohol, biofuels, alcohol fuel, alternative fuel, anti-knock fuels, leaded gasoline, tetraethyl lead, oil shortage, petroleum shortage, Charles Kettering, Henry Ford, Harry R. Ricardo.
This paper examines the attitudes of three historically important engineers regarding the use of ethanol as an alternative fuel. Henry Ford and Charles Kettering are among the most significant American mechanical engineers, while Harry R. Ricardo of England was the most significant figure in early 20th century mechanical engineering there. All three had definite opinions concerning ethanol as both a direct substitute for petroleum and as an anti-knock additive when blended at 10 to 20 percent volume with gasoline. Their opinions are significant today with the resurgence of ethanol and other alternative fuels.
Ethanol was a well known fuel at the dawn of the automotive age and was in competition with petroleum on two levels – direct substitution for gasoline and octane boosting in blends with gasoline. The two levels of competition are not always easy to separate, especially since the main competitor on the additive level was “leaded” gasoline produced by a company called “Ethyl.” (Technically, the additive is tetraethyl lead).
Leaded gasoline was an economic success from 1926 until 1976, and in fact, its discovery at Charles Kettering’s General Motors laboratory was among the most celebrated achievements of automotive engineering. It was often portrayed as the result of genius, luck and a great deal of hard work. It is now considered to be a catastrophic failure and is banned for environmental and public health reasons.*
Ethanol, on the other hand, always seemed doomed to failure. Engineers often quipped that ethanol was “the fuel of the future—and it always will be,” since it was more expensive than leaded gasoline from the 1920s through the 1980s. It was, in a way, the red-headed step child of the energy industry. It was usually omitted from industry histories and discussions about fuel choices. Today ethanol can only be considered a success, although controversy about various efficiency, biodiversity and carbon footprint issues still attends its use. And in fact, it is for that very reason that the lack of historical perspective seems like such a glaring lacuna in the record and a reminder that technological roads not taken may still need to be remembered someday. (Note: A discussant on the panel where this paper was presented objected to considering ethanol a success in the modern context because, he argued, the technology was subsidized and environmentally problematic. In the author’s opinion, this is historically inappropriate and impossibly restrictive).
One of the great success stories exemplifying the power of science and invention in the 1920s and 30s was the General Motors development of leaded gasoline. The history of leaded gasoline was told in Thomas A. Boyd’s 1957 memoir and biography of Charles Kettering, Professional Amateur and Rosamond Young’s 1961 biography, Boss Ket. Also, public relations articles and a few references in scientific papers may be found about the Ethyl controversy. In 1978 Thomas Hughes discussed inventive styles using the example of the discovery of tetraethyl lead, which he said occurred in the style of an heroic or Edison-like individual effort in that it involved testing of all possible combinations. In addition, the 1983 book Ethyl, historian Joseph C. Robert describes the General Motors development of leaded gasoline in a heroic style without noting that alternatives were seriously considered. Even as late as 1996, an article about Kettering saw the development of leaded gasoline in the context of a successful and inventive solution to the knock problem. The issue of lead poisoning – well appreciated in the 1920s and by the 1980s the basis of an international ban on leaded gasoline – was treated dismissively. “An outcry arose over the possibility” of a public health problem, the article said, even though it was far more than a simply outcry over a mere possibility. Kettering’s views on alternative fuels, as described below, were not considered. Another book, Dying for Work, also explored leaded gasoline from the public health side of the issue but not from the variety of technological alternatives.
One book that dealt with both sides of the technological issue and described alternative fuels within the anti-knock context was the 1983 book, Boss Kettering. Historian Stuart Leslie noted the lack of success for ethanol and attributed it to economic and energy efficiency problems. Only a few other authors put the issues into the context of the variety of fuel types. For instance, the difficulty facing alternative fuels technologies in the competition with petroleum and leaded gasoline additives was explained in 1949 as basically a problem of scientific prejudice by S.J.W. Pleeth and as an instance of industry dominance by Forbidden Fuel by Bernton, Kovarik and Sklar in 1982. The controversy over leaded gasoline and its alternatives was also described in a March, 2000 article in The Nation magazine.
One reason that this literature may now seem dated is that new documentation has emerged concerning the General Motors research efforts led by Charles Kettering and the origins of the alternative fuels industry. Some of this paper is based on the new documentation.
A curve in the road not taken: historiographic issues
The preference for “success stories” in history of technology is often seen as whiggish, and historians such as John Staudenmier have argued that more attention should be paid to the “roads not taken.” 
The fallacy of whig history, usually defined as viewing the past through the optics of the present, is that we fail to understand the past. The history of alternative fuels as written to date presents us with a similar problem. When an unsuccessful technology finally becomes successful, there is a danger of viewing the present through our misunderstanding of the past.
A focus on the success of petroleum technologies is evident in many histories of energy and automotive fuels that tend to exclude non-petroleum alternatives. In recent years, ethanol production for anti-knock additives and straight fuel use (called E-85) has emerged as a major industry. US industry has the capacity in place or under construction for 12 billion gallons of ethanol per year, or about 10 percent of the overall gasoline supply. A similar capacity for ethanol and biodiesel is in place or under construction worldwide. A variety of biodiesel technologies also emerged, with a 2006 production level of 250 million gallons and rapid increases projected there also. Alternative fuels, according to the New York Times, had come of age. Thus, previous historical explanations based on the failure of alternative fuels are clearly antiquated.
We might note in passing that a lack of historical context has had modern policy implications. As noted elsewhere, carbon neutrality and biodiversity are modern expectations by which we now tend to consider alternative fuels, but these yardsticks are flawed if we do not also take into account the original special motives that attended the birth of these technologies and that still impel their political trajectories.
The discussion about motives for development of a technology must, to some extent, be tentative. Yet an exploration of inventors motives may give insight into the question of social construction versus determinism in history of technology. The deterministic view would hold that the intrinsic properties of a technology tend to follow a predictable or even inevitable path independent of social or political influence. The socially constructed view is that human action shapes technologies through conflicts and negotiations between social interests.
In this situation, where technologies are nearly equivalent in attributes, it may be possible to observe this negotiation between social interests more closely. The alternative fuels in question – alcohols and vegetable based bio-diesel – are nearly equivalent with gasoline and diesel fuels. Although there are many specific differences, they are both combustible in the same types of engines and both groups fall into the same general price range for consumers. Yet the two groups have vastly different social and economic implications for the industries in question, and thus provide insight into the social interests that originally attempted to negotiate these technologies.
Ethanol and the rhetoric of the technological sublime
The cultural and political significance of alternative fuels goes far beyond the simple substitution of one ordinary product for another. Ethanol, biodiesel and other renewable fuels have long been seen in a broader symbolic context rather than simply a narrow technological one. Opponents have seen ethanol technology as a scheme for robbing taxpayers to enrich farmers, as a way to turn food for the poor into fuel for the rich, as compounding soil erosion problems, and as a marginally useful enhancement or replacement fuel for a transportation system that is poorly designed in the first place.
For advocates, ethanol has had the potential for revolutionizing agricultural economics, for dispelling city smog, and for curbing the power of the petroleum industry over the economy. In other words, ethanol was good for rural development, public health and national security. Proponents could also see in ethanol the potential to help strike balance between city and farm and the prospect of civilizing and humanizing industrial machinery. In addition, the idea that agriculture and biological resources could be primary sources of energy, the idea that humankind could live on solar “income” rather than fossil fuel “capital,” has held a fascination for automotive and agricultural engineers, including Kettering and Ricardo, as we will see.
The literature of ethanol is filled with the rhetoric of the technological sublime, and no better example can be found than Alexander Graham Bell’s 1917 National Geographic article in which he predicts that alcohol will be the fuel of the future when the oil runs out. It “makes a beautiful, clean and efficient fuel…” Bell goes on to say: “Alcohol can be manufactured from corn stalks, and in fact from almost any vegetable matter capable of fermentation… We need never fear the exhaustion of our present fuel supplies so long as we can produce an annual crop of alcohol to any extent desired.”
This same level of rhetoric is graphically depicted in the symbolism used at the 1902 Paris alcohol fuel exposition. On the cover of the exposition’s proceedings, a muse with an overflowing bouquet of roses looks down over the steering wheel with a confident smile. She is a portrait of wisdom and beauty, firmly in control of a gentle machine which seems appropriately located in some lush flower garden. (See Fig. 2 )
This rhetoric frequently attends the birth of any new technology, and of course there is nothing surprising about the high hopes of French automobile enthusiasts or Alexander Graham Bell. Their rhetoric was also probably a factor in the way automotive engineers viewed the technology. What is surprising, however, is the comparison between the rich historical record and the very poor modern understanding of the history of renewable energy.
Promoting the agrarian vision
The economic and political conflict between rural and urban interests is considered one of the most important dynamics of the 19th and 20th centuries, and populist agrarian movements were a major factor in US and European politics. The issue set was often seen in terms of balancing the agrarian values that might civilize and humanize industry against the use of technologies that could lift the burden of physical drudgery from rural life.
Henry Ford, a complex and not always attractive figure in American history, believed that the industrial revolution would eventually make the amenities of urban living available in rural areas. He saw a need for industry to decentralize and build small factories that would make a greater use of surplus agricultural products. This would bring about a better balance between urban and rural economies, he believed, and the United States would see “as great a development of farming as we have had in the past twenty years in manufacturing.” 
The son of a prosperous farmer who was said to dislike farm chores, Ford’s program to use technology to improve agriculture was described by historian Raynold Millard Wik in a Technology and Culture article in 1962. Ford tried all kinds of things, Wik said, “… to introduce scientific technology into American agriculture,” including “experiments to produce alcohol as a motor fuel by distilling it from farm crops.” When World War I threatened to create a gasoline famine, “he announced in 1915 that … the new Fordson tractor would be designed to burn alcohol as well as gasoline; thus the supply of fuel would be unlimited.”
Thus, Wik appropriately placed Ford and his interest in ethanol at the very nexus of this rural – urban contest, and also briefly noted that Ford tried to promote alcohol in 1920 and again in the 1930s. Yet Wik missed not only many additional facts, but also the broader context of a generation of “discontented agrarians” in Europe and the US that had similar aims. The competition between ethanol and petroleum was an arena where the competition between rural and urban interests played out, and Ford played a significant early role.
To step backward briefly: The history of alternative automotive fuels in the United States actually begins with Samuel Morey’s experiments in the 1820s, but on a broad scale, it was the Civil War tax on beverage alcohol that pushed a booming industrial alcohol lamp fuel business into obscurity and (as agrarians argued) opened the door for the Pennsylvania oil boom. In return, agrarians made it a high priority to eliminate this debilitating tax in the 1890s and early 1900s. (See Fig. 3).
For example, in 1897 American agrarians noted that the European experience with free alcohol laws meant that an increase in the price of farm commodities and the opening of new markets in heating and lighting.  By 1905, it was common for Americans to read about German potato alcohol winning markets for farmers in a battle against the Standard Oil monopoly.  The German alcohol fuel program had started in the late 1890s with government prizes for research into engine and appliance use of alcohol along with financial support for new alcohol distilleries. In 1903, the Reichstag approved a tariff on oil to expand the farm alcohol production infrastructure. Potato alcohol was seen as the “final solution of the oil problem and the means by which the grasp of the great [Standard oil] monopoly will be broken.”  A network of small farm “Materialbrennereien” stills was put in place. Estimates of its size vary, but USDA put its 1903 production at 37 million gallons and by 1914, some 6,000 distilleries were said to be produced 66 million gallons of alcohol per year.  (In contrast, 1903 French industrial alcohol was at 10 million gallons per year and English was 3.7).
Of course, the idea of value-added agricultural processing, by which bulky crops are concentrated into more valuable products, is as old as moonshining. But the German program was politically innovative. The government was faced with two strong political movements: on the one hand, the agrarian movement, which wanted strong markets and high farm prices; and the political left on the other hand, which wanted cheap food for urban workers. When the German government brought agricultural products into industrial markets on a mass scale, it made agrarians happy while at the same time keeping food prices low.
Thus, German Kaiser Wilhelm found he could “satisfy the discontented agrarians” by encouraging the use of alcohol fuel from potatoes. The oil industry was the only sector left out in the cold, and since Germany imported all of its oil, the agrarian movement was able to strike a nationalistic note. The lesson would not be lost on Henry Ford.
In the US, agrarians hoped that every American farmer could have his own supply of heat, light, and power at low prices, just like German farmers. “Advocates look forward with hope to a big change in the farmer’s life,” the New York Times reported. “If the law accomplishes what is hoped, it will … make a revolution on the farm,” the paper said. 
Agrarians found a strong ally in Theodore Roosevelt. The outspoken “trust-buster” bitterly attacked the Standard Oil’s monopoly in a variety of ways, and an alternative fuel was obviously a means of loosening Standard’s grip on the economy. As an alcohol tax relief bill passed the House in 1906, Roosevelt tried to rally Senate support in a letter to Congress: “The Standard Oil Company has, largely by unfair or unlawful methods, crushed out home competition. It is highly desirable that an element of competition should be introduced by the passage of some such law as that which has already passed in the House, putting alcohol used in the arts and manufacturers upon the [tax] free list.” 
While alcohol could easily replace kerosene as a lamp fuel, just as kerosene replaced alcohol in 1862, the bigger question was what would happen with the new automobiles being developed. Before the final passage of the free alcohol bill, the Washington Post noted: “Henry Ford, the Detroit automobile manufacturer, is preparing to meet the new conditions with an automobile that will use the new fuel instead of gasoline.” Tests in Ford’s labs showed that 52-horsepower engines ran at 60 horsepower with alcohol as a fuel. 
The Senate passed the bill May 24, 1906, and the New York Times again noted the low cost of alcohol. “The new fuel and illuminant will utilize completely an important class of agricultural crops and byproducts thus benefiting in a double sense the farms and villages throughout the country,” an editorial said.
American enthusiasm for the new fuel increased even more when the German government shipped in 1907 “a comprehensive collection of apparatus employed in the production and consumption of denatured alcohol for the exhibition in Jamestown.” The 300th anniversary celebration of the founding of Jamestown was opened by President Roosevelt and had, in the industrial alcohol section, a variety of German and American irons, coffee roasters, stoves, lamps and engines all running on alcohol. This same exhibit, which had been in Paris and Italy in previous years, went on to tour fairs and National Grange meetings in the US until at least 1909.
As the nation’s largest farm organization, the Grange, was strongly Prohibitionist, since half of its voting members were women. In 1909, the Grange was divided in its support for denatured ethanol in fuel, with many purists believing that any support for distillers of alcohol would be a “deal with the devil.” As the debate unfolded, the pro-alcohol fuel faction was politically damaged by secretly taking money from distillers, and as a result, the farm community was no longer solidly behind the ethanol idea.
Ford’s support continued. When Michigan’s state Prohibition law took effect in 1917, Ford said it would be “a shameful waste” to let the plants go idle. “Denatured alcohol can be used successfully as a fuel for automobile engines” Ford said. Ten years later, Ford told a New York Times reporter that ethyl alcohol was “the fuel of the future” which “is going to come from fruit like that sumach out by the road, or from apples, weeds, sawdust — almost anything. There is fuel in every bit of vegetable matter that can be fermented. There’s enough alcohol in one year’s yield of an acre of potatoes to drive the machinery necessary to cultivate the fields for a hundred years.” Throughout his life, Ford hoped that these kinds of developments would bring on “the greatest era of prosperity and happiness we have ever known.”
Ethanol was not the only farm product that could be used by industry, of course. All kinds markets already existed, and the research needed to expand these markets was increasingly taken on by land-grant universities and the US Dept. of Agriculture by the 1930s. Targets for research included newsprint from Southern pine, milk into a silk-like fabric, desert shrubs into rubber, coffee beans into dyes, cornstalks into paper, and starch-laden grains into alcohol.
The general idea of adding value to crops by preparing them for industrial markets had no specific label until the 1920s, when Henry Ford’s Dearborn Independent newspaper published a lengthy article by William J. Hale urging the nation to launch a major alcohol fuel development program. In “Farming Must Become A Chemical Industry,” Hale explained an idea for a blend of science, economics, and philosophy which Hale labeled chemurgy—from the Egyptian word chem (from which “chemistry” is derived) and the Greek word ergon which meant “to work.” Hale said that the idea was to find new uses for farm crops and put chemistry to work for agriculture.
With Ford’s backing, the Chemurgy concept moved quickly from an abstraction to concrete proposals for farm relief during the Depression. The parallel to the old German model for agrarian development seems clear. Chemurgy did not take off in the 1930s for a variety of reasons, especially because the administration of President Franklin Roosevelt was unhappy with Midwestern conservatives in general and Henry Ford and the Chemurgists in particular.
In 1935, Ford sponsored a Chemurgy conference. The Farm Chemurgic Council organization was established to encourage research on farm products, and many ideas were explored at the conference. But the most explosive issue was ethanol as a fuel. Heated debates broke out as Chemurgists insisted that ethanol was technically feasible and economically beneficial. Oil industry representatives and their allies in the farm community argued that alcohol fuels were technically poor substitutes for gasoline and that there was no sense in making motorists pay for farm relief. Between the two warring groups there appeared little room for agreement. 
The Chemurgist proposals received a cool press reception. A New York Times editorial said: “Alcohol was glorified as a miracle-worker which would permanently place the farmer beyond the pale of distress… . [they] talked of alcohol at 10 cents a gallon—an impossible price even if corn sold for only half of what it brings now.” The editorial acknowledged that alcohol was technically a good fuel for high compression engines, but concluded that ideas about farmers making money by raising weeds for ethanol was nothing more than “Jules Verne dreaming.” 
Ford continued to support the Chemurgists, although as World War II opened, his agrarianism was overshadowed by his antisemitism and his support for German Nazi leaders. In 1937, a manufacturing company in Atchison Kansas was turned into an alcohol fuel plant. The new industry was beset by growing pains and hostility from the oil industry, and was never able to get on its feet. (See Fig. 4). While the experience of producing alcohol proved of tremendous importance in creating synthetic rubber quickly in World War II, Ford’s farm Chemurgy movement died out by the 1960s.
British nationalism and racing spirit
While agrarianism was a key motivation for Henry Ford, nationalism was another typical motivating factor for the development of alternative fuels technologies from the beginning of the 20th century. Germany, as already noted, was a leader in challenging the oil industry with domestically produced alcohol fuel at the turn of the century, thus enhancing national security. The English government was also interested in ethanol for fuel but tended to be more cautious in embracing it. A committee on industrial alcohol formed in 1905 reported that the main question “would be one of price” and put off a full research program until later. 
At the time, very little was known about how fuel burned in an internal combustion engine, but a British engineering consultant named Henry Ricardo was determined to change that. Ricardo is best known today for his scientific development of the internal combustion engine in Europe and the US. His designs included the advanced Rolls-Royce airplane engines like the Crecy and the Merlin, considered the most efficient internal combustion engines ever built. In the 1920s and 30s, he was also known for the patented “Ricardo Discol racing spirit” – a type of alcohol fuel.
In 1913, Ricardo began testing samples of different petroleum and alternative fuels from around the world – the first methodical research in a laboratory setting. His program of research tended to be “concerned more with learning about existing fuels than improving them,” said S.J.W. Pleeth, chief chemist for the Cleveland Discol Co. “Of particular importance was his discovery of the anti-knock value of the alcohols, methanol and ethanol.” And although it was not seen as terribly important at the time, “no single project has been of greater significance than the initial programme to investigate knock in the petrol engine,” his biographer wrote in 1968.
Ricardo’s initial motives had to do with the lack of scientific information about engine knock and a nationalistic concern about British research. In his memoirs, Ricardo remarked that he was surprised in the pre-World War I years to learn how little research and development work was being carried out by British engine manufacturers, most of whom were paying royalties to German firms which were then using the royalties for research. “My friends all regretted that this should be so, for it both hurt their pride and limited their activities as engineers,” Ricardo wrote. “Looking back over those years it seems shameful that we in England should have allowed ourselves to lag so far behind in the development of aeroplanes and engines, but it was lack of incentive, not ability, that brought this about,” he said.
World War I changed this picture dramatically, as French and British scientists actively researched military engines and fuels. Ricardo’s work focused primarily on the mechanical solutions to engine optimization. For example, he developed cross-head engine for the British tank corps in 1916 which “exhibits no-knock properties.”
But the engine knock problem was not so easily solved, and the idea that oil would run out and that other fuels would be needed was so generally accepted that even a 1915 boys’ book entitled Modern Inventions, devoted to zeppelins and submarines, had a chapter entitled “Alcohol Motors and the Fuel of the Future.”  
An Alcohol Motor Fuel Committee was created in 1918, originally as part of the defense research effort. It was made up of representatives of the petroleum executive, the Home Office, the Admiralty, the Board of Agriculture and Fisheries, and others, including Ricardo. The committee was charged with considering sources of supply, methods of manufacture and costs of production for alcohol fuel.  Tests by various researchers found that mixtures of alcohol with 20 percent benzene or gasoline “run very smoothly, and without knocking.”  One researcher worked with London busses and said: “In all respects the [alcohol] fuel compared favorably with petrol [gasoline], and exhibited the characteristics of other alcohol mixtures in respect of flexibility, absence of knocking and cleanliness.” The main finding of the research was that a large scale switch from petroleum was technically feasible. “We are fast squandering the oil that has been stored in the fuel beds, and it seems so far as our present knowledge takes us that it is to the fuels experimented with that we must turn for our salvation.” 
Ricardo was involved with many of these engine and fuel experiments in one way or another. He tested fuels at various compression ratios up to the point where they would begin knocking, or what he termed the “highest useful compression ratio.” Ethyl alcohol had a 7.5 value, with commercial gasolines then available at 4.5 to 6. He concluded that the low burning rate of alcohol lessens the tendency to knock, and that, using toluene as the reference point at 100 anti-knock, alcohol had a 130 rating – the highest of any other fuel – despite its drawbacks. 
In his seminal 1923 book, The High Speed Internal Combustion Engine, he said: “…It is a matter of absolute necessity to find an alternative fuel. Fortunately, such a fuel is in sight in the form of alcohol; this is a vegetable product whose consumption involves no drain on the world’s storage and which, in tropical countries at all events, can ultimately be produced in quantities sufficient to meet the world’s demand, at all events at the present rate of consumption. By the use of a fuel derived from vegetation, mankind is adapting the sun’s heat to the development of motive power, as it becomes available from day to day; by using mineral fuels, he is consuming a legacy – and a limited legacy at that – of heat stored away many thousands of years ago. In the one case he is, as it were, living within his income, in the other he is squandering his capital. It is perfectly well known that alcohol is an excellent fuel, and there is little doubt but that sufficient supplies could be produced within the tropical regions of the British empire…” 
|(Fig. 5) Another advertisement for Cleveland Discol, the alcohol fuel company that sold Ricardo’s patented racing fuel, London Times, 4 June, 1937, 13.|
Ricardo’s thinking seems to reflect a thread that is found among an earlier generation of inventors who feared the depletion of fossil fuels. Naval architect and inventor John Ericsson, for example, said: “The time will come when Europe must stop her mills for want of coal…. [Industry will move to the tropics] where an amount of motive power may be obtained many times greater than now employed by all the manufactories of Europe.” And Augustine Mouchot, a French engineer, said: “The time will arrive when the industry of Europe will cease to find those natural resources, so necessary for it. Petroleum springs and coal mines are not inexhaustible but are rapidly diminishing in many places. Will man, then, return to the power of water and wind? Or will he emigrate where the most powerful source of heat sends its rays to all? History will show what will come.”
These expressions of hope for a human destiny beyond fossil energy seem to have fallen out of fashion by the end of the 1920s. When a second edition of Ricardo’s book was issued in 1928, the fear of oil depletion had abated. Ricardo’s poetic paragraphs on renewable energy were redacted, and in their place was the following sober statement: “When we review the progress of mechanical engineering in the past we find that each new line of development starts with a period of experiment and groping, during which a wide range of types is evolved. By a process of elimination this range is very soon whittled down to one or two survivors; in the final choice of these survivors, chance plays often quite as important a part as merit. Ripe seeds of invention everywhere abound, and it awaits only a certain combination of need, of circumstance and, above all, perhaps, chance, to decide which shall germinate.”
In 1921, Ricardo patented racing fuels called RD1 and RD2 (for Ricardo Discol) that contained methanol and ethanol, acetone and small amounts of water. These were widely used on race tracks throughout Europe and the US in the 1920s and 30s, but were regarded as a “pleasant foible” rather like the smell of castor oil around the race track.  Still, his advocacy of ethanol for general use was challenged in the 1920s by technical problems with alcohol production (such as the need for better azeotropic processing) and by the development of tetraethyl lead by Charles Kettering’s research group at General Motors.  As the technical problems cleared up, and ethanol blending could be more easily accomplished in the 1930s, Ricardo worked with National Distillers Co. and Shell Oil on an alcohol fuel blend called “Discol” that soon became very popular on a commercial level.  Ricardo’s Royal Society biography passed this over simply as ‘racing spirit’,  but it was certainly more than that. The formula was said to have “monopolized” racing fuels. Ads in the London Times boasted that “Racing Motors Run on Cleveland * Ricardo * Dicol.”  (See Figs. 4 and 5).
Hundreds of other advertisements and articles about Cleveland Discol, usually without mention of Ricardo or his patents, are found in the British newspapers and magazines from the 1930s until 1968. Cleveland Discol was historically the second-longest of any commercial alcohol fuel blending program in the world, with Brazil’s program being the longest-lived.
It is interesting that Ricardo continued to be involved with alternative fuels yet chose to give the issue little prominence. Perhaps S.J.W. Pleeth, a chemist for Discoll who might have worked with Ricardo, summed it up best when he noted that the bias aroused by the use of alcohol as a motor fuel has produced research results that are incompatible with each other. Countries with considerable oil deposits, such as the US, or which control oil deposits of other lands, such as Holland, tend to produce reports antithetical to the use of fuels alternative to petrol; countries with little or no indigenous oil tend to produce favorable reports. “The contrast between the cases presented is most marked. One can scarcely avoid the conclusion that the results arrived at are those best suited to the political or economic aims of the country concerned or the industry sponsoring the research. We deplore this partisan use of science, while regretfully admitting its existence, even in the present writer.” Here Pleeth says that the social and political construction of the technology supercedes its intrinsic properties to an extent that seems impossible to overcome.
Helping General Motors survive a future oil shortage
The deepest “special motives” for using alternative fuels are found with Charles Kettering and his research assistants at General Motors in parallel to the development of leaded gasoline. In an unpublished legal history, company lawyers noted: ” … An important special motive for this [tetraethyl lead / leaded gasoline] research was General Motors’ desire to fortify itself against the exhaustion or prohibitive cost of the gasoline supply, which was then believed to be impending in about twenty-five years; the thought being that the high compression motors which should be that time have been brought into general use if knocking could be overcome could more advantageously be switched to alcohol. “
Between the early 1900s and the mid 1920s, it was widely believed that oil was running out and that alternative fuels would be needed. As early as 1906, for example, representatives from the Detroit Board of Commerce told a U.S. Senate hearing that auto manufacturers worried “not so much [about] cost as … supply” of fuel. Similar fears of oil shortages were evident at the end of World War I, when demand for fuel skyrocketed and quality of fuel declined. Geologists estimated that only 20 or 30 years worth of oil were left in the U.S. and a “gasoline famine” was likely.
Oil production figures relative to reserves demonstrated the alarming trend. In 1920, oil consumption was roughly 500 million barrels per year, with reserves at 7.2 billion. By 1925 oil consumption was over 750 million barrels per year with reserves at 8.5 billion. The horizon of oil availability had dropped from 14 years to 11. 
“Within the lifetime of most of the present drivers of automobiles, there will be no more gasoline,” said the head of the New York section of the American Chemical Society. “It is a serious thing to contemplate, particularly from the standpoint of the [auto] manufacturer.”
Automotive manufacturers worried that oil depletion would cause “a calamity, seriously disorganizing an indispensable system of transportation,” according to a 1919 article in Scientific American. “The burden falls upon the engine. It must adapt itself to less volatile fuel, and it must be made to burn the fuel with less waste….Automotive engineers must turn their thoughts away from questions of speed, … comfort and endurance.” 
A “new fuel supply to replace gasoline” would be needed, and in the post World War I years, ethyl alcohol (ethanol) was the most obvious candidate. Thousands of news articles appeared extolling the virtues of alcohol as a fuel.  Ethanol was often praised by top scientists as the natural fuel of the future. 
Charles Kettering and his staff at Dayton, Ohio were well aware of the pending oil shortage and its possible impact on automakers like General Motors. In 1919, Kettering’s DELCO had merged with GM to become the core of the company’s research division. Kettering and lab assistants Thomas Midgley and T.A. Boyd concluded around 1921 that “this year will see the maximum production of petroleum that this country will ever know.”
How should Detroit adapt to an oil-short future? Low compression engines for low-quality fuel? In a 1919 Scientific American article, Kettering urged engineers to take a longer view. He argued that low quality fuels would also run out and low compression engines would use them up even faster. On the other hand, if the fuel could be improved in some way, engines could be developed with higher compression ratios, which would give better mileage, which in turn would extend fuel supplies.
Most histories of Kettering’s anti-knock fuel research simply move from oil shortages to the discovery of anti-knock leaded gasoline. But in his Scientific American article, Kettering said he saw two types of solutions: high percentage and low percentage. A low percentage solution would be very small amounts of additives that were known knock suppressors such as bromine, iodine, tin, selenium, arsenic and sulfur. Eventually, GM research settled on lead in the form of tetraethyl lead.
On the other hand, Kettering and his researchers quietly believed that the high percentage approach would be the key to Detroit’s ultimate survival. A high percentage of alcohol – 15 to 20 percent in gasoline – would improve the anti-knock quality of gasoline as much as three grams of tetraethyl lead. In the process, markets would be opened for a fuel that would keep Detroit in business when oil ran out.
In an unpublished 1921 Society of Automotive Engineers paper, Kettering’s research assistant Thomas Midgley noted that the US Geological Survey’s projected nine year oil reserve horizon was “a rather gloomy picture for the future success of our automotive industry.” The most important alternative fuels were shale oil, benzene from coal tar and alcohol. Shale oil was rejected as too high in olefins and benzene from coal was unsuitable since it would mean five times more coal production. But alcohol was renewable and was “right” from the standpoint of cost, boiling point and equivalent heating value as compared with gasoline. Midgley said:
“The most direct route which we now know for converting energy from its source, the sun, into a material that is suitable for use in an internal combustion motor is through vegetation to alcohol… It now appears that alcohol is the only liquid from a direct vegetable source that combines relative cheapness with suitability (although other sources might be found)… Alcohol will stand very high initial compressions without knocking, and at high compressions is smooth and highly satisfactory.”
There were disadvantages with alcohol, he noted. With a lower heating value of 80,000 BTU per gallon, compared to about 120,000 for gasoline, efficiency (mileage) would suffer unless alcohol was used in higher compression engines. Difficulties with engine starting, occasional separation from gasoline in blends, and materials compatibility were other problems he noted. Even so, “while some of the difficulties are real,” engines can be “readily adapted to utilize alcohol at a much faster rate than the production and distribution of alcohol can be increased.”
Even if the automotive engineering questions were fairly clear cut in 1921, the sources of alcohol were problematic. In another paper, Midgley estimated that it would take sixty percent of the entire starch and sugar crops in the US to replace gasoline. With 2.7 billion bushels of corn produced in the US, a total ethanol production of 7.5 billion gallons would be possible but “very unlikely.” 
Thus Midgley and Kettering arrived at a conclusion that seems as if it might have come from yesterday’s headlines. Rather than farm crops, cellulose would have to be used for future fuels. “The material from which motor fuel should be derived in the future is known as cellulose… It is suitable from a chemical standpoint, it is readily available, it is easily produced and its supply is renewable.” The process would need work, but if yields could be doubled, “the danger of a serious shortage of motor fuel would disappear.”
GM invested in cellulosic ethanol research, and Midgley’s assistant, T.A. Boyd, was sent to study the possibilities in the summer of 1920 with Harold Hibbert at Yale University. Hibbert had been outspoken about cellulosic ethanol and the threatened oil shortage. “Does the average citizen understand what this means?” he asked. “In from 10 to 20 years this country will be dependent entirely upon outside sources for a supply of liquid fuels… paying out vast sums yearly in order to obtain supplies of crude oil from Mexico, Russia and Persia.” Alcohol from cellulose would solve the problem, he said.
While Hibbert was enthusiastic, Boyd wrote of his confusion to Midgley. “I find that it will be impossible to cover the literature … in four weeks, even counting ten hours a day.”  Boyd and Midgley returned to the low percentage approach to anti-knock additives and developed leaded gasoline (tetraethyl lead) in December of 1921. But they, and Kettering, continued to see it as a temporary expedient.
“Unquestionably alcohol is the fuel of the future,” Midley wrote in a private memo to Kettering in May, 1922 – six months after leaded gasoline had been discovered.  Similar statements are found in a dozen internal memos and, more guardedly, in external publications. But more important is the position that tetraethyl lead occupied relative to oil shortages and the ultimate fuel of the future. As Midgley and Boyd wrote in 1922: “Some means must be provided to bridge the gap between petroleum and the commercial production of large quantities of liquid fuels from other sources. The best way to accomplish this result is to increase the efficiency with which the energy of gasoline is used and thereby obtain more automotive miles per gallon of fuel…. The principle effect of the use of antiknock compounds will be much further removal of the time when the threatened exhaustion of our petroleum reserves will actually occur.”
Thus, the evidence is overwhelming that Charles Kettering and his General Motors research division were fully prepared for a non-petroleum future in the early 1920s. However, as leaded gasoline began to be marketed, and profits began rolling in to the cash-strapped General Motors company, the optimistic views of ethanol changed radically. A 1924 joint venture with Standard Oil Co. to form the Ethyl Gasoline Corp. was also a major influence on corporate outlook.
In October of 1924, a catastrophic miscalculation led to at least 17 refinery deaths and many dozens of permanently debilitating injuries. GM and Standard very nearly abandoned TEL, and Kettering and Midley knew that there were many types of anti-knock fuels available.
And yet, when the decision was made to defend leaded gasoline, Midgley and Kettering claimed that alternatives either did not exist or were impractical: We found out that with ordinary natural gas we could produce certain [antiknock] results and with the higher gravity gasolines, the aromatic series of compounds, alcohols, etc., we could get the high compression without the knock, but in the great volume of fuel of the paraffin series we could not do that.
While Kettering’s defense was nuanced, Midgley made an obviously false case to defend leaded gasoline: “So far as science knows at the present time, tetraethyl lead is the only material available which can bring about these [antiknock] results, which are of vital importance to the continued economic use by the general public of all automotive equipment, and unless a grave and inescapable hazard exists in the manufacture of tetraethyl lead, its abandonment cannot be justified.”
Both Midgley and Kettering were replaced from the management of the Ethyl Corp. in the spring of 1925, perhaps because of differences over the originally transitional idea of tetraethyl lead versus the apparently permanent commitment that Standard Oil and General Motors were making.  Perhaps Kettering had some hope for his new alcohol and iron carbonyl fuel, called “Synthol,” introduced in 1925. Or perhaps more research would have helped. Some of the profits from the sale of leaded gasoline continued to fund investigations into photosynthesis in later years. The Kettering foundation, it was said in 1938, “has made great strides toward analyzing and perhaps duplicating … chlorophyll (which)… ‘will open up an entirely new conception of things that can be done.’”
Leaded gasoline was finally abandoned in the 1980s, when overwhelming evidence of its severe impact on public health was finally accepted.  By then, history had forgotten that if an alternative fuel was needed in the future, Kettering believed there would always be the possibility of “capturing the energy of the sun … through agricultural products. 
Agrarianism, nationalism and corporate longevity were among the early motivations for research into alternative fuels. Public health was a secondary but nevertheless important issue in the development of alternative fuels, as it eventually reversed the success of the fuel additive tetraethyl lead.
For Henry Ford, ethanol fit the agrarian ethic, as the creation of new markets for farm products was an important collateral benefit of alternative fuels technology. For Harry Ricardo, alternative fuels were an answer to the problem of oil depletion and a research area where his country seemed to be falling behind. For Charles Kettering and the research team at General Motors, alternative fuels like ethanol were the ultimate fuel of the future, but a transitional gasoline additive like tetraethyl lead was needed to raise fuel octane and compression ratios.
It’s interesting that in later years, only Henry Ford continued to express idealism in this area of technology. Kettering and Ricardo apparently regarded the issue as settled by economic realities and corporate priorities. The problem may be seen as involving the struggle between engineers and business elites. Kettering and his engineers originally viewed tetraethyl lead as a bridge to a better source of energy, but they were undercut by the corporations who removed them from management directions in 1925 and told them to go work on something else. Ricardo, as an independent consultant, would have been subject to some of the same pressures.
In the 21st century, the criteria by which alternative fuels are judged are rather far afield from the original motives. The new criteria may include biodiversity, carbon-neutrality and other environmental impacts. But the original motives are still in play – rural development and agrarianism, nationalism and independence in fuel supply, and long-term adaptability for automobile manufacturers when sources of oil become problematic.
* Tetra-ethyl lead, the active ingredient in leaded gasoline, was developed in 1921 by General Motors and marketed in a joint venture with Standard Oil by the “Ethyl” Corp. It was used in over 80 percent of all US gasoline by the mid-1930s. It was phased out in the US between 1976 and 1986 and in Europe between 1995 and 2000. It has been removed from the fuel systems in nearly all other nations in the world in the early years of the 21st century at the insistence of the World Health Organization.
 T.A. Boyd, Professional Amateur (New York: E.P. Dutton, 1957); also Rosamond Young, Boss Ket (New York: Longmans, Green & Co., 1961), 162.
 Graham Edgar, “Tetraethyl Lead,” paper to the American Chemical Society, New York, (Sept. 3-7, 1951), reproduced by the Ethyl Corp.; T.A. Boyd, “Pathfinding in Fuels and Engines,” Society of Automotive Engineers Transactions, April 1950, 182-183; Stanton P. Nickerson, “Tetraethyl Lead: A Product of American Research,” Journal of Chemical Education 31, (November 1954), 567.
 Thomas P. Hughes, “Inventors: The Problems they Chose, The Ideas They Have, and the Inventions they Make,” in Patrick Kelly and Melvin Kransberg, Eds., Technological Innovation: A Critical Review of Current Knowledge (San Francisco: San Francisco Press, Inc., 1978), 177.
 Joseph C. Robert, Ethyl: A History of the Corporation and the People Who Made It (Charlottesville, Va.: University Press of Virginia, 1983), 122- 123.
 Oliver E. Allen, “Kettering,” American Heritage of Invention and Technology, Fall 1996. Accessible on the web at: http://www.americanheritage.com/articles/magazine/it/1996/2/1996_2_52.shtml
 David Rosner and Gerald Markowitz, Dying For Work: Workers Safety and Health in the Twentieth Century (Indianapolis: Indiana University Press, 1986).
 Stuart Leslie, Boss Kettering (New York: Columbia University Press, 1983)
 S.J.W. Pleeth, Alcohol: A Fuel for Internal Combustion Engines (London: Chapman & Hall, 1949).
 Hal Bernton, Bill Kovarik, Scott Sklar, The Forbidden Fuel: Power Alcohol in the 20th Century (New York: W.B. Griffin, 1982).
 Jamie Lincoln Kitman, “The Secret History of Lead,” The Nation, 20 March, 2000.
 These include 80 linear feet of the unclassified files of Thomas Midgley at the General Motors Institute Alumni Foundation Collection at Kettering University, Flynt Mich. These papers have changed the picture of how tetraethyl lead research was approached. See Bill Kovarik, “Charles F. Kettering and the 1921 Discovery of Tetraethyl Lead In the Context of Technological Alternatives,” Society of Automotive Engineers, Fuels & Lubricants Conference, Baltmore, Md., 1994; also “Henry Ford, Charles Kettering and the Fuel of the Future,” Automotive History Review, Spring 1998, No. 32, 7-27; ” Ethyl The 1920s Environmental Conflict Over Leaded Gasoline and Alternative Fuels,” Paper to the American Society for Environmental History Annual Conference March 26-30, 2003 Providence, R.I.
 John Staudenmier, Technology’s Storytellers (Oxford: Oxford University Press, 1988).
 Daniel Yergin, The Prize: The Epic Quest for Oil, Money & Power (NY: Simon & Schuster, 1991).. Also see John M. Blair, The Control of Oil (NY: Vintage Books, 1978); Anthony Sampson, The Seven Sisters: The Great Oil Companies and the World They Shaped (NY: Viking, 1975); James Ridgeway: Powering Civilization; the Complete Energy Reader (NY: Pantheon, 1982); Harold Williamson, et al., The American Petroleum Industry, The Age of Energy, 1899-1959 (Evanston, Ill.: Northwestern University, 1963).
 “Building New Horizons,” Renewable Fuels Association annual industry outlook 2007, accessed on the web at http://www.ethanolrfa.org/media/outlook/
 Susan Moran, Biofuels Come of Age as Demand Rises, New York Times, 12 September, 2006
 Bill Kovarik, “Back to the Fuel of the Future,” paper to the Life Sciences Symposium, University of Missouri, March, 2007.
 As a recent example of this, Prof. Paul Erlich said in a Stanford University panel discussion on Sept. 5, 2007 that he believed “Biofuels are a fraud,” without any further discussion.
 Langdon Winner, “The moral significance of the material culture,” in Andrew Feenberg and Alastair Hannay Technology and the politics of knowledge Bloomington : Indiana University Press, c1995
 Raymond Millard Wik, “Henry Ford’s Science and Technology for Rural America,” Technology and Culture, Summer 1963. Also Henry Ford, My Life and Work (Garden City, N.Y.: Garden City Publishing Co., 1922).
 Lyle Cummins, Internal Fire (Warrenton, Pa.: Society of Automotive Engineers, 1989), 81. Also, Horst Hardenberg, Samuel Morey and his Atmospheric Engine (Warrendale, Pa.: Society of Automotive Engineers, Feb. 1992), SP922; also Katharine Goodwin and Charles E. Duryea, Captain Samuel Morey: The Edison of His Day (White River Junction, Vermont: The Vermonter Press, 1931); also Gabriel Farell Jr., Capt. Samuel Morey who built a Steamboat Fourteen Years Before Fulton, (Manchester, NH: Standard Book Co., 1915). Ray Zirblis, “Was Samuel Morey Robbed?” Vermont Life, (Autumn, 1994) 53.
 Free Alcohol Law, Senate Finance Committee Hearings on HR 24816, Feb. 1907, Doc. No. 362.
 “Alcohol Used in the Arts: Congressional Committee on the Proposed Repeal of the Tax in Session Here,” New York Times, 12 November, 1897, 2.
 “Potato Alcohol vs Standard Oil,” New York Times, June 18, 1905, p. SM3.
 “A Blow at American Oil,” New York Times, 15 January, 1903, 9.
 US Department of Agriculture. Industrial Alcohol: Uses and Statistics, USDA Bulletin No. 269 (1906). Also, Col. Sir Frederic Nathan, “Alcohol for Power Purposes,” The Transactions of the World Power Congress, London, 24 September – 6 October, 1928. A variety of sources are not in agreement. According to a 1906 account, some 72,000 small fuel distilleries operated (See “Free Alcohol Distilleries,” New York Times, 13 September, 1906. The source of the statistic is the U.S. Consul General in Berlin.) Also, according to Irish engineer Robert Tweedy, “Every motor car in the empire was adapted to run on alcohol. It is possible that Germany would have been beaten already [by 1917] if production of alcohol had not formed an important part of the agricultural economy.” (See Robert N. Tweedy, Industrial Alcohol (Dublin, Ireland: Plunkett House, 1917).
 The Kaiser’s New Scheme,” London Times, 24 April, 1902, reprinted in the New York Times, 24 April, 1902, 9. Also see “German Agrarians,” The Youth’s Companion, 13 April, 1899, 188, APS Online. Brett Fairbairn, Democracy in the Undemocratic State: The German Reichstag Elections of 1898 and 1903 (Toronto: University of Toronto Press, 1997).
 “Still on every farm to turn out alcohol,” New York Times, 2 January, 1907.
 “President Flays the Oil Trust,” Washington Post, 5 May, 1906, 1.
 “With the automobilists,” Washington Post, 22 May, 1906, 8.
 “The New Cheap Illuminant,” New York Times, 25 May, 1906.
 “Gets Alcohol Apparatus: Jamestown exposition will receive machinery from Germany,” Washington Post, 25 March, 1907, 9.
 “Big concerns back reciprocity fight New York Times, 11 June, 1911, 6. Also, personal communication, Leroy Watson, National Grange legislative director, 10 April, 2007, Washington D.C.
 “Ford Sees Use for Breweries,” Washington Post, 14 November, 1916, 2.
 “Ford Predicts Fuel from Vegetation,” New York Times, 20 September, 1925, 24.
 “Ford Predicts new era of Prosperity,” New York Times, 4 June, 1938, 2.
 Christy Borth, Modern Chemists and Their Work (New York: Bobbs-Merrill, 1939), 69.
 David E. Wright, Agricultural editors Wheeler McMillen and Clifford V. Gregory and the farm chemurgic movement. Agricultural History 22 March 1995.
 Borth, 44.
 ”Alcohol and the Farmer,” New York Times, 12 May, 1935, E8.
 Bill Kovarik, “Fuel of the Future,” (footnote 9, above).
 Homer S. Fox, “Alcohol Motor Fuels,” Supplementary report to “World Trade in Gasoline,” Bureau of Domestic and Foreign Commerce, U.S. Dept. of Commerce Monograph, Trade Promotion Series No. 20., Washington, D.C., 1924.
 Pleeth (n. 8 above), 55.
 The autobiography of Sir Harry Ricardo, Ricardo Story: Pioneer of Engine Research, SAE Historical Series, (Warrendale, PA: Society of Automotive Engineers, 1992), forward by Martin Howarth.
 The autobiography of Sir Harry Ricardo, 116.
 H.A. Tarantous, “Motors Cars of 1924 Better in Every Way,” New York Times, 6 January, 1924, A2.
 V.E. Johnson, “Alcohol Motors and the Fuel of the Future,” Chapter 19, in Modern Inventions, (London: TC & EC Jack, Ltd., 1915) 286 – 293.
 Fox, (n 41 above), 10.
 Harold B. Dixon, “Researches on Alcohol” as an Engine Fuel,” Society of Automotive Engineers Journal, December, 1920, 521.
 G.J. Shave, Imperial Motor Transport Conference, Oct. 18-21, 1920, cited in G.W. Monier-Williams, Power Alcohol: Its Production and Utilization (Oxford, UK: Oxford Technical publications, 1922).
 H.R. Ricardo, “The Influence of Various Fuels on Engine Performance,” Automobile Engineer, February, 1921.
 H.R. Ricardo, The high speed internal combustion engine (London: Blackie & Son, Ltd., 1923).
 William C. Church, “John Ericsson,” Scribners Monthly, April 1879, 835-859; Also see “The Sun Motor,” Manufacturer and Builder, 10 October 1888, 232.
 A. Mouchot, “The Heat of the Sun and its Industrial Uses,” Machines Driven by Solar Heat – Sun-Machines: Manufacturer and Builder, August 1870, 231.
 H.R. Ricardo, The high speed internal combustion engine, 2nd edition, (London: Blackie & Son, Ltd., 1928).
 Pleeth (n. 8 above), 148.
 Pleeth, (n. 8 above), 222.
 The Ricardo Story: The autobiography of Sir Harry Ricardo, Pioneer of Engine Research, SAE Historical Series, (Warrendale, PA: Society of Automotive Engineers, 1992).
 William Hawthorne, “Harry Ralph Ricardo. 26 January 1885 — 18 May 1974″ Biographical Memoirs of Fellows of the Royal Society, Vol. 22. (Nov., 1976), 358-380.
 Advertisement for Cleveland Discol, The British Alcohol Motor Spirit, London Times, 29 November, 1935, 13.
 Pleeth (n. 8 above), 227.
 N. P. Wescott, Origins and Early History of the Tetraethyl Lead Business, June 9, 1936, Du Pont Corp. Report No. D-1013, Longwood ms group 10, Series A, 418-426, GM Anti-Trust Suit, Hagley Museum & Library, Wilmington, Del., 4.
 Free Alcohol Hearings, US Senate Finance Committee, 1906, Statement of James S. Capen, Detroit Board of Commerce, 59.
 David White, “The Unmined Supply of Petroleum in the United States,” Paper presented to the Society of Automotive Engineers annual meeting, 4 – 6 February, 1919. Also see George Otis Smith, “Where the World Gets Oil and Where Will our Children Get It When American Wells Cease to Flow?” National Geographic, February, 1920, 202.
 Crude Petroleum – Production, Value, Foreign Trade and Proved Reserves 1859 – 1970, Series M 138-142, Historical Statistics of the United States (Washington DC: US Government Printing Office, 2000).
 D.H. Killeffer, “Sees New Fuel to Replace Gasoline,” New York Times, 4 January, 1925, A3.
 “Declining Supply of Motor Fuel,” Scientific American, 8 March, 1919, 220.
 Some 152 popular and scholarly articles under the heading “Alcohol as a Fuel” can be found in the Readers Guide to Periodical Literature between 1900 and 1921; the New York Times database holds 408 articles on the subject “alcohol and fuel” between 1900 and 1925. In addition, about 20 references to papers and books written before 1925 are found in the Library of Congress catalog; a 1933 Chemical Foundation report lists 52 references before 1925 on alcohol fuels; a 1944 Senate report lists 24 USDA publications alone on the subject of alcohol fuels before 1920; and several technical books from the period document hundreds of references from the 1900 – 1925 period.
 Alexander Graham Bell, National Geographic, Feb. 1917, 131.
 T. A. Boyd, “The Early History of Ethyl Gasoline,” Report OC-83, Project # 11-3, Research Laboratory Division, GM Corp., Detroit Michigan, (unpublished) June 8, 1943, Midgley unprocessed files, GMI Alumni Foundation Collection, Kettering University, Flynt, Mich. (Hereafter noted as GMI), 73.
 Charles F. Kettering, “Studying the Knocks,: How a Closer Knowledge of What Goes on In the Cylinder Might Solve the Problems of Fuel Supply,” Scientific American, 11 October, 1919, 364.
 Thomas Midgley, “Our Liquid Fuel Reserves,” unpublished paper to the Indiana Section of the Society of Automotive Engineers, 12 October, 1921, (n. 68, GMI).
 Midgley, “Our Liquid Fuel Reserves.”
 Boyd, (n. 68 above), 54.
 Harold Hibbert, “The Role of the Chemist in Relation to the Future Supply of Liquid Fuel,” Journal of Industrial and Chemical Engineering, September, 1921, 841.
 TA Boyd to Midgley, July 20, 1920, in Boyd, (n. 68 above), 71.
 Midgley to Kettering, May 23, 1922, (n. 68, GMI).
 Thomas Midgley and T.A. Boyd, “The Application of Chemistry to the Conswervation of Motor Fuels,” Journal of Industrial and Engineering Chemistry, September, 1922.
 U.S. Public Health Service, Proceedings of a Conference to Determine Whether or Not There is a Public Health Question in the Manufacture, Distribution or use of Tetraethyl Lead Gasoline, PHS Bulletin No. 158, (Washington, D.C.: U.S. Treasury Dept., August 1925), 6.
 “Radium Derivative $5,000,000 an ounce / Ethyl Gasoline Defended,” New York Times, 7 April, 1925, 2
 Sloan to Du Pont, 28 March, 1925, Government Trial Exhibit No. 678, U.S. v. du Pont et al., US District Court, Chicago, 1953. Kettering was to be replaced at the April meeting of the Ethyl board.
 “Work on New Type of Auto and Fuel,” New York Times, 7 August, 1925; also “New Auto, Fuel to Save Costs are Announced,” United Press, 6 August, 1925.
 Harry M. Davis, “The Promise Science Holds,” New York Times, 25 July, 1937, 104.
 Kitman (n. 10 above).
 C.S. Mott, Kettering Oral History Project, Interviewed by T.A. Boyd, 19 October, 1960, (n. 68, GMI).
 David F. Noble, America by Design, (Oxford: Oxford University Press, 1979), 33.