288 PHYSICS. 



Morton, Mayer, and Thomas have published results of measurements 

 of Edisou-s lamp jS^o. 154. The resistance of the lamp when cold was 

 123 ohms; when giving 1.9 candles, 82 ohms ; and when giving 18 cau- 

 dles, 75 ohms. The current strength was measured on a tangent galva- 

 nometer, the constant of which was determined on a copper voltameter. 

 "When the lamp was giving 0.07 of a candle, it was consuming 0.445 

 weber of current, equivalent to 0.024 horse-power. When it gave 14 

 candles, the current was increased to only 1.079 webers, equivalent to 

 O.llG horse-power. This latter result gives 120 candles to the horse- 

 I)ower of current, or, assuming 60 per cent, efficiency in the machine, 

 72 candles per effective horse-power. — {Ann. Ghini. Phys., Y, xx, 275, 

 June, 1880.) 



Swan has continued his experiments on incandescent lighting, begun, 

 as he claims, as long ago as 18G0. He uses carbon filaments made from 

 parchment paper, 3 inches long, 0.01 inch in diameter, weighing -J^^ grain, 

 sealed in exhausted globes. One of these has burned continuously for 

 three months. — {Xature^ xxiii, 104, December, 1880.) 



