In the year 1885 the Franklin Institute of the State of Pennsylvania published a special report on test results of lamps submitted for comparison purposes. This report was published as a supplement to the Journal of the Franklin Institute, Sep 1885. The report is rather extensive and deals with topics that usually are not of general interest to lamp collectors. Certain information on the lamps was extracted from the report, however, and is conveyed here.

The lamps that were tested were: Stanley-Thompson (44-volt), Woodhouse-Rawson, Weston (70 & 110-1/2 volts), Edison (94-100 volts), Stanley-Thompson (96-volt), and White (later known as Vitrite and Luminoid Company's "Luminoid"). The Brush-Swan and Bernstein Companies were invited to submit lamps but did not. The lot of Woodhouse-Rawson lamps were obtained from the Van de Poele Company. The Stanley-Thompson lamps had been made by the Union Switch and Signal Company of Pittsburg. The Weston lamps had been made by the United States Electric Lighting Company.

The Weston lamps had "tamidine" filaments. Gun-cotton in the form of flat sheets was treated chemically to separate the nitryl from the cellulose. The resulting cellulose product was a tough, firm, translucent substance from which the strips were cut in a sinuous form and carbonized. The carbon was rectangular in cross section, but was placed in the lamp so that at the shanks, the longer side of the rectangle was in the line of the shanks, instead of at right angles as in most other lamps. The connections were made at the terminals with minute steel screw bolts and nuts setting up with platinum washers. The bending of the carbon turned the long side of the rectangle so that it lay in different directions at different points. The lamp was mounted on a wooden base surrounded by a brass ring. The wires were led down through holes in the wood to the bottom of the base, where one was soldered to a ring and the other was held in place by a small screw, which was concentric with the ring and projecting below its plane. The socket contained two spring clamps against which the terminal ring and screw of the lamp pressed, the lamp being held in place by a lug on the brass ring fitting into a groove in the socket.

The Edison lamps submitted were similar in appearance to those in the marketplace. The carbon was made from bamboo fiber. Lamps employed the usual screw socket.

The carbon in the Woodhouse-Rawson lamps was rectangular in cross section and was cemented by a very neat joint to two platinum wires, which were kept apart by a glass bridge, and then they passed through the base of the lamp. The wires had small loops formed in their ends, the loops being made rigid by imbedding the ends in the glass. Two spring hooks in the socket hook into these loops, making contact. The lamps in the test were used with Swan sockets.

The Stanley-Thompson lamps apparently had filaments made of thread. The lamps were made under the Stanley-Thompson patents. In the small 44-volt lamp the filament was cemented to platinum wires that were kept apart by a glass bridge and then passed through the base of the lamp. The glass bulb of the lamp was set in a hollow in a wooden base and secured by a cement of plaster of Paris. The wires went through the wood to two small screws.

All lamps except for the Edison gave the appearance of the filaments having been treated in a hydrocarbon vapor. The Weston filaments had only a slight treatment.

The White lamps had an appearance similar to the Woodhouse-Rawson lamps. The filaments were cemented to platinum wires that were separated by a glass bridge, and had loops in their ends for hook connections in spring sockets.

A picture of the lamps, sans the White, is shown below.