Limited loads. Congestion. Resulting delay and expense therefrom….
Solution:—Electrically driven trucks, covering one-half the street area, having twice the speed, with two or three times the carrying capacity….Development necessary:—Running gear—easy. Motor driver—easy. Control—simple. Battery—(?)13
Electric trucks and automobiles, as opposed to trolleyed streetcars and trains, depended on the lead-acid storage battery. It was thrillingly silent, but the payoff was a tire-flattening weight of lead plates, not to mention cells full of corrosive fluid sloshing between negative and positive poles, emitting an odor almost as acrid as horse piss. There were two alternatives, each with its own liabilities. Gasoline-powered vehicles were hard to start (their engines had to be hand-cranked into life, and could break a man’s arm on the kickback) and laborious to drive, and called for crunching gear changes whenever they sped up or slowed down. In addition they were smoky and blaringly loud. Steam engine cars had to be water filled with annoying frequency, and in winter they took as long as forty-five minutes to warm up.*3 Being at least powerful, once they started puffing, they dominated the majority of the nation’s eight thousand–vehicle “horseless carriage” market. But until one or another drive mode was made both practical and cheap, there was unlikely to be much lessening of the amount of manure on city roads.14
Edison’s Cortlandt Street notebook indicated a willingness to bet that gearless, nonpolluting electric power would win out—if not for automobiles, at least for delivery trucks and cabs. What he had to do was to invent a reversible galvanic cell that was dramatically lighter and cheaper. It should compete with the high energy density of gasoline and be as clean as steam. It should generate current without surges or slumps, and enable many miles of traction before a recharge was necessary. It should tolerate short-circuits, rough riding over country roads, overcharges, and reductions to zero voltage. Admittedly these were huge imponderables, but his nature was to rise to such challenges. After ten years of carving up and crushing mountains, the scientist in him longed for a return to the atomic logic of electrochemistry.15
He refused to accept the shibboleth that lead, iron, and sulfuric acid were the only reagents that would ever generate enough current to move a car independently. It was “very beautiful in theory” but flawed in practice “because of the inherent destructive influence” of its liquid electrolyte.16 At best, the massing of six or eight lead-lined, hard rubber cells*4 per vehicle caused a 15 percent loss of efficiency. Maintaining anything like that ratio for long required more skill and patience than most “automobilists” possessed—not to mention strength in lifting dud units out, a job that usually required two men. “If Nature had intended to use lead in batteries for powering vehicles,” Edison declared, “she would not have made it so heavy.”17
Without realizing that the question mark at the end of his Cortlandt Street notes portended the most agonizingly difficult project of his career, he began to look for an electrochemical yin-yang, a perfect counterbalance of positive and negative, attraction and repulsion, charge and recharge, and energy to mass, that surely existed somewhere in “Nature.”18 If not yet achieved, it was implicit in the primary battery invented a hundred years before by Alessandro Volta, the father of applied electricity: a cylindrical pile of acid-soaked cardboard disks, alternately separating thick medallions of silver and zinc, or copper and zinc. The damp layers reacted with the metal layers, generating a flow of power through the cell, from positive anode to negative cathode, the moment it was connected to an outside conductor. While copious, the flow was irreversible, draining away until the cell “died.”
Gaston Planté’s invention in 1859 of a secondary lead-acid battery that stored infusions of outside current amounted to a technological innovation almost as great as Volta’s. As a boy chemist and teenage electrician, Edison had shocked and burned himself into an intimate understanding of both kinds of cells. But in adulthood, after nearly disfiguring his face with a splash of nitric acid, he had wondered about the feasibility of a reversible traction battery filled with an alkaline electrolyte, perhaps doing away with plate electrodes altogether, so as not to waste its energy on the movement of dense metal.19
He took his first step toward this radical idea in 1889, when he manufactured an improvement to the Lalande-Chaperon cell, a primary battery that counterposed electrodes of positive zinc and negative iron in an aqueous solution of potassium hydroxide.*5 Its closed construction inhibited evaporation of the electrolyte and encouraged him to believe that a cell just as noncorrosive might be made rechargeable by an outside dynamo. To that end, for almost a year, he had been conducting regenerative experiments with copper oxide electrodes, dunking them into caustic solutions of varying strength. The results were unsatisfactory, because the copper either oxidized too much or would not reverse at all. He was to try fifty other combinations of metals and minerals, looking for “an entirely new voltaic combination,” before the summer of 1900 was out.20
“LOVE IS A FOREIGN THING”
In their different ways of operating, Edison’s two eldest sons ludicrously resembled the poles of a malfunctioning storage battery. Tom was the corrosible negative element, doomed to attract clinging ions like Mr. Friedlander, while William was the hard end, pulsing out a wild spray of electrons that sometimes threatened an explosion. Anything could touch him off—an imagined slight, a rumor, a landlord’s demand for arrears—and just as quickly he could be moved to effusive declarations of love or good intent. He was as needy as his brother, but whereas Tom craved affection more than money, to William a check would always suffice.
Somehow in July Tom got the idea that his expectations as the son of an industrial tycoon were misplaced. Instantly he suspected a plot fomented by Mina to disinherit him.21 His paranoia was plain in a letter received by Walter Mallory, the large, lugubrious engineer who ran the Edison Portland Cement Company.
Will you be so kind as to let me know as soon as possible whether my father has disinherited me or not….
It is Mrs. Edison and a few of his friends? who have been instrumental in this matter….Love is a foreign thing to my father but the world will know the true state of affairs pretty soon. Lies have been told him about me and my wife and he believes me [sic]—Let him do so but by God he will regret it and I will show him and the Miller gang that there is one son who is not a fop.22
So much for poor Tom, who draped his spindly body in elegant suits and wore high stiff collars to hide an attenuated neck. (William, in contrast, looked like a middleweight wanting to strip and fight.) The “Miller gang” were Mina’s clannish relatives, who had always looked down on her stepfamily.
William went on to complain about the annoyance of having to earn a living. He was running an automobile agency in Washington, D.C., and not doing at all well:
I am compelled to seek a job as my meagre income is not suitable for my maintenance. My father if he was a true father would certainly look after my welfare. He never takes the trouble to find out whether I am dead or alive but I’ll tell you what Mallory…I am tired of all this business and something dirty is going to happen before I meet my length in soil.23
Mallory forwarded the letter to his boss, who for some time had been allowing William $2,160 a year, more than the average salary of a college professor.*6 Edison ignored it, but when Blanche followed up with a hysterically scrawled six-page screed saying that the children of “The Greatest Man of the Century” should not have to live in such poverty, he permitted himself a rare show of anger.
I see no reason whatever why I should support my son, he has done me no honor, and has brought the blush of shame to my cheeks many a time. In fact he has at times hurt my feelings beyond measure. For more than fifteen years I supported my family on less than two thousand a year, & we lived well and after allowing you as much as I do monthly to have you talk in the way you do sh
ows an utter lack of gratitude. Let your husband earn his money like I did. I will continue to send the monthly installment until such a time but in no case will I loan any more money or increase the monthly amount.24
ALL MY DUCATS
In October Edison’s first two patents covering “new and useful improvements in reversible galvanic cells or so-called ‘storage batteries’ ” heralded his self-rediscovery as a chemist just when he had to accept that he would never become another Andrew Carnegie. The hard economics of mining and milling forced him to abandon his expensive new venture in New Mexico, where the gold sand was too poor to process, and simultaneously close the iron-extraction plant he and Mallory had built at Ogdensburg, New Jersey, with grandiloquent hopes, nine years before.25
Henceforth, apart from a scheme they had to adapt his long kiln and leftover Ogdensburg machinery to manufacture portland cement, Edison intended to spend as much time as possible with test tubes and galvanometers: “I am putting all my ducats in the storage battery.”26
The patent applications made clear that he did not expect early success. He wrote that he had improved the performance of an alkaline cell by using the absolute neutrality of magnesium to prevent zinc being “deposited in spongy form” on the negative electrode during recharge. Instead, he got sizable clumps of it if the latter element was copper oxide. But zinc itself was the problem. It was simply too soluble in an alkaline solution, the clumps tending to degrade after a while, rapidly reducing discharge capacity, as “other experimenters with batteries of this type” had already found.27
The last statement would return to haunt Edison. It suggested familiarity with the work of an obscure Swedish scientist, Ernst Waldemar Jungner, whose development of an alkaline automobile “accumulator” was so similar and so simultaneous with his as to arouse suspicions of mutual espionage—were they not separated by two oceans and multiple barriers of language. Jungner, too, had invented a variant of the Lalande battery some years back, and his first alkaline silver-cadmium cell had been patented in Germany on 26 August 1899, about two months after Edison began testing polarizations of zinc and copper in solutions of caustic potash. Around the same time Jungner had also applied for, but not yet received, an American patent for his basic battery.28
If Edison had any detailed knowledge of it at the time he executed his own first application, he would have to have read a recent article by Jungner in Elektrochemische Zeitschrift, forbiddingly entitled “Ein primär wie sekundär benutzbares galvanisches Element mit Elektrolyten von unveränderlichen Leitungsvermögen.” This was not implausible, because he subscribed to a sister publication, Elektrotechnische Zeitschrift, and employed translators to help him keep up to date with foreign innovation.29
At any rate, the second of his 15 October patent applications showed a sophisticated understanding of cadmium-element electrochemistry, along with pride that he had conquered a problem that had defeated all “previous experimenters.”30 In language of the utmost precision, Edison described an invention more complex than any he had devised since his quadruplex telegraph of 1874. Its construction began with the rolling and annealing of two thin, rectangular nickel plates that were lugged to face each other, like infinity mirrors, once they had been respectively impregnated with elements of cadmium and copper. To that end he polished them with red heat and hydrogen before attaching the pockets—nickel too, and flat—to keep the cell as elegantly slim as possible.
The pockets and plates were perforated for later immersion in alkaline liquid. Next came the extremely intricate process of preparing two metallic powders to fill the pockets. One, for the positive plate, consisted of finely divided cadmium; the other, for the negative, was a similar division of copper oxide. Although so far the assembly of the cell had been a counterposing of opposites, the elements had to be manufactured differently. He obtained his cadmium by electrodeposition onto a platinum cathode, peeling off from it ribbons “exceedingly finely divided and filamentary in form, and of great purity.” He washed them in water to remove any trace of residual sulfate, then packed the filaments into the pockets—tightly enough to give them “coherence” yet not so tightly that the pocket lost porosity.
Illustration from Edison’s cadmium-copper storage battery patent application, 15 October 1900.
Delicate as this operation was, it did not match the difficulty of dividing the copper oxide. Here was where Jungner (or whomever else Edison accused of preceding him) had failed to create an effective depolarizer. All their efforts had been blocked by “the production of a small amount of copper salt, bluish in color, and which was soluble in the alkaline liquid.” As the salt circulated and dissolved, it rapidly rotted both positive and negative elements, especially zinc. The containing cell had to be oversize to compensate, while its resistance increased in tandem.
“In consequence,” Edison wrote, “reversible batteries using copper oxide as a depolarizer have never remained in commercial use and are now obsolete.” His battery was unique in that he divided the oxide chemically, making it as smooth as the purest talc. “If…there is a single piece, no matter how minute, of dense copper, or even if the finely divided copper is compressed sufficiently to materially increase its density, a soluble hydroxid of copper will be formed.” To avoid any such salt-causing impediments, Edison obtained his powder by reducing copper carbonate with hydrogen at the lowest possible temperature. This made it light, anhydrous, and insoluble, the last property being essential to the efficiency of storage battery electrodes. “When the copper has been thus secured in finely divided form, it is molded into thin blocks of the proper shape to fit snugly in the pockets of the plates….”
By now, two-thirds of the way through his application, Edison was clearly reveling in the intricacy of what he was describing (“Grand science, chemistry. I like it best of all the sciences.”) and in the terminology needed to protect every nuance from infringement.31
After the copper [filled] plates have been molded, they are subjected in a closed chamber to a temperature of not over five hundred degrees Fahrenheit for six or seven hours until the copper is converted into its black oxid (CuO). If higher temperatures are required, the density of the black oxid will be undesirably increased. After being thus oxidized, the copper oxide blocks are reduced electrolytically to metallic copper, and are then reoxidized on charging by the current until they are converted into the red oxid (CU2O). In this form, the blocks are inserted in the perforated pockets 6 of the desired plates, which are then ready for use.
The finely divided copper originally obtained by reduction by hydrogen as explained, may be lightly packed in the perforated receptacles without being first oxidized by heat as described. I find, however, that when this is done, the efficiency is not so high as when the copper is first oxidized to the black oxid, because, unlike the cadmium, it is not filamentary in form, and its particles as originally produced do not apparently effect an intimate electrical contact with each other.
The last stages of fabrication were to brace and insulate the loaded plates in a nickel frame, connect them electrically, and slot the whole assembly—densely engineered, yet as easy to lift as an attaché case—into its nickel sleeve. It was then topped up with a solution of 10 percent sodic hydroxide and hermetically sealed, except for a one-way valve for the release of hydrogen bubbles on recharge. Two neatly protruding pole tips, positive and negative, completed the cell, which could be stacked with others, to stream as much power as desired.
In a final paragraph of description, Edison exulted in the duality of his design. During discharge, the cadmium became cadmous oxide and the cupric oxide became copper. During recharge, the metals and oxides converted back to their original state, and even the water in the electrolyte “respectively decomposed and regenerated, leaving the liquid in exactly the same condition and quantity after each discharge.” There was so little evaporation that the cell hardly needed its refill c
ap. “In fact I find by practice that by interposing between the plates thin sheets of asbestos…which have been merely moistened with the alkaline liquid, nearly as good results can be secured as when the plates are actually immersed.”32
It was a state-of-the-art battery that paid tribute, in its alternations of metal and damp fiber, to Volta’s electric pile of a hundred years before.
WHEN SEEN AND FOLLOWED
Even as he signed his two new patents, Edison knew that he had done little to challenge the crude power of the lead-acid car battery. There were several things wrong with his cadmium-copper cell, starting with the prohibitive expense of both metals.*7 It was impractical, with an output of only .44 volts, and even if cheaper electrodes could be made to generate more energy per unit weight, the delicacy of its assembly boded ill for commercial production. Nor, despite Edison’s claims, had he entirely solved the problem of blue-salt precipitation. By November he was back in his chemical laboratory, searching again for a perfect yin and yang of reversible galvanic power.33
It was a month otherwise enlivened by a letter from William, who seemed to have forgotten the paternal wrath he had recently incurred. Writing now in the guise of a concerned sibling, he reported that Tom’s showgirl wife*8 had deserted him and was abusing her former connections:
Marie Edison was seen going into the “Haymarket,” one of New York’s worst joints, with two strange men and a bad woman. She was making the rounds of the “Tenderloin” [District] and boasting to everybody that she was Edisons daughter in law and his favorite….She seems to think she is playing all of us for “suckers.” When seen and followed she was drunk and telling everything to these dirty people.34
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