248 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



rather thick-set, with a smoothly shaven face and long bushy 

 white hair. lie was quiet and unassuming in demeanor, and 

 courteous and agreeable in personal intercourse. lie enjoyed 

 the friendship of the leading men of science not only of Par- 

 is, but of the world. 



Mallet has made the interesting observation that a wire 

 placed east and west and traversed by an electric current 

 suffers an apparent alteration in weight, due to the effect of 

 the earth's magnetism upon it. The experiment, which was 

 unsuccessfully attempted by Faraday, was made by attach- 

 ing to the arm of a delicate balance a series often horizontal 

 wires fastened to a strip of dry poplar three meters long, 

 twenty-five millimeters wide, and five millimeters thick, the 

 ends of the wires being branched and bent downward so as 

 to dip into the mercury cups at each end. When the cur- 

 rent of ten Grove cells was passed from east to west through 

 the wires placed east and west, the side of the balance to 

 which they were attached sensibly preponderated ; while, 

 when the current passed from west to east, the other side 

 w r ent down. These results may be observed with a single 

 wire only a meter long. 



Plante has constructed what he calls a rheostatic machine 

 by combining a number of condensers (made of mica and tin- 

 foil) so as to be easily charged from a secondary battery in 

 quantity, and discharged in tension. The commutator is a 

 long cylinder of hardened caoutchouc, having longitudinal 

 metallic bands, and traversed by bent copper wire (for the 

 two objects named). Metallic springs are connected with 

 the two armatures of each condenser, and fixed on an ebon- 

 ite plate on each side of the cylinder, which is rotated. A 

 series of sparks can be got between the branches of the ex- 

 citer in this arrangement, quite like those from electric ma- 

 chines with condensers. The discharges are always in the 

 same direction, and the loss of force is less than in induction 

 apparatus. A great many discharges can be had without 

 the secondary battery being perceptibly weakened, as each 

 discharge removes only a small quantity of electricity. 



In a subsequent paper Plante has given a description of 

 some of the effects obtained with this new rheostatic ma- 

 chine, which, as above stated, consists simply of a series of 

 condensers so arranged as to be charged from a secondary 



