"Dr. Isaac Adams, residing at Gloucester, Mass., testified for the defendants in the suit of the Edison Electric Light Company vs. the United States Electric Lighting Company, on the Edison filament lamp patent, No. 223,898 (hereinafter referred to as the 'Filament Record'), regarding his experiments with incandescent lamps. He was educated as a physician, but while abroad became interested in the manufacture of Geissler tubes, which he took up as a commercial undertaking upon his return to this country, in 1864. Being familiar with the properties of carbon, he, during 1865-6, made a number of lamps just as he had made his Geissler tubes, but with carbon burners about an inch to an inch and a quarter long, about three-sixteenths of an inch in width and from .005 to .01 of an inch thick; these carbons varied in resistance from .69 to 1.2 ohms, and were made by filing or scraping a block or strip of carbon as thin as he dared to, then dipping it in sugar and then reheating, making it tough and dense. The carbons were cut from gas-retort carbon, blocks of plumbago, carpenters' pencils or from a mixture of lampblack, powdered coke and molasses. Fig. 4 (from Filament Record, Vol IV, p. 2691) shows how these lamps were made. A is a glass globe, B a carbon slip; D D copper or brass extension of platinum conductors; P P platinum conductors; S double sleeve of glass fused together and surrounding the platinum conductors; J joint of fused glass shutting out atmosphere."The vacuum employed was as perfect as Dr. Adams could make it with his improved mercury pump. Great difficulty was experienced by Dr. Adams in maintaining a vacuum because of the cracking of the glass around his large platinum leading-in wires (No. 16 B. W. G.), made necessary to carry the large current (from 11.5 amperes to 18.8 amperes) required by his carbons. This difficulty was not overcome until he produced a special character of glass from which to make his globes, having the same coefficient of expansion as the platinum. The question of dates was somewhat involved in Dr. Adams' mind when he testified, and it seems probable that no perfect globes were made before 1867. When cross-examined in the above case Dr. Adams said (Vol. IV, p. 2716):
"'I had no idea at that time"' - 1867-9 - "' of having done anything of any special merit, as I thought the introduction of a piece of carbon into a globe to a person who was in the habit of making Geissler tubes was not much of a trick; but I was interested in the fact as to whether or not the big platinum that I put in the glass would hold, because I have always considered - did then, and do now - that I made an invention there which was a useful one. That was my interest in the lamp, and that was about all the interest I had in it. * * * Introducing platinum wires of relatively large cross section was the novelty."'"This shows quite clearly what was the state of Dr. Adams' mind. He did not make a practice of measuring the resistance of his lamps"'because'" he says, '"I was not interested in that direction. I was not proposing to get up a system of lighting, not at all. I was simply making a lamp."' He dropped the matter entirely in 1869. He had no records of the life of any of these experimental lamps and could only guess at the life of any of them. It is perhaps unfortunate that Dr. Adams should have regarded his work from the standpoint of the glass-worker rather than that of the electrician, but the fact is that he had not advanced beyond the conceptions of King or Roberts, except so far as the enclosing globe and the leading-in wires were concerned, guaranteeing a better vacuum."