STARR’S INCANDESCENT LAMP
Starr’s Incandescent Lamp, 1845.
This consisted of a short carbon pencil operating in the vacuum above a column of mercury.
J. W. Starr, an American, of Cincinnati, Ohio, assisted financially by Peabody, the philanthropist, went to England where he obtained a patent in 1845 on the lamps he had invented, although the patent was taken out under the name of King, his attorney. One is of passing interest only. It consisted of a strip of platinum, the active length of which could be adjusted to fit the battery strength used, and was covered by a glass globe to protect it from draughts of air. The other, a carbon lamp, was the first real contribution to the art. It consisted of a rod of carbon operating in the vacuum above a column of mercury (Torrecellium vacuum) as in a barometer. A heavy platinum wire was sealed in the upper closed end of a large glass tube, and connected to the carbon rod by an iron clamp. The lower end of the carbon rod was fastened to another iron clamp, the two clamps being held in place and insulated from each other by a porcelain rod. Attached to the lower clamp was a long copper wire. Just below the lower clamp, the glass tube was narrowed down and had a length of more than 30 inches. The tube was then filled with mercury, the bottom of the tube being put into a vessel partly full of mercury. The mercury ran out of the enlarged upper part of the tube, coming to rest in the narrow part of the tube as in a barometer, so that the carbon rod was then in a vacuum. One lamp terminal was the platinum wire extending through the top of the tube, and the other was the mercury. Several of these lamps were put on exhibition in London, but were not a commercial success as they blackened very rapidly. Starr started his return trip to the United States the next year, but died on board the ship when he was but 25 years old.