Intelligence and Miscellaneous Articles. 519 



necessary to produce it will be always the same, and that also what- 

 ever be the temperature of the instrument, provided it is the same 

 in both limbs — a condition which is easily realized. The barometric 

 pressure and the hygrometric state of the air clearly do not affect the 

 results, for the apparatus is hermetically sealed. Finally, as the 

 liquid is always the same, we can reproduce by this instrument at 

 any time a quantity of gas corresponding to an invariable quantity 

 of electricity taken as standard, the whole operation resolving itself 

 into reading a volume which is always the same, without the 

 necessity of any correction, while with the ordinary voltameter the 

 corrections for temperature, pressure, and the tension of vapour are 

 far from being negligible. 



In order that the instrument may be used over and over again, 

 the water decomposed must be re-formed at each operation ; this is 

 the object of the platinum wires at the top of the bulb where 

 the detonating gas accumulates. When a spark is passed, 

 the gases reunite, the acidulated water again fills the bulb, and the 

 instrument is ready for a new operation. The apparatus may be 

 made more or less sensitive by filling it before sealing with air 

 below the atmospheric pressure. — Comptes Rendus, March 22, 1886. 



EXPERIMENTS IN THERMOELECTRICITY. 

 BY MM. PILLEUR AND E. JANNETAZ. 



We have endeavoured to ascertain if, when we heat a given 

 point of a conductor having a schistous texture, thermoelectric 

 currents are produced in it. 



Our experiments extended to zinc, tin, iron, and copper. The 

 schistous or long-grain texture was imparted to them by carefully 

 drawing them out, an operation performed under our superintend- 

 ence in the workshops of M. Pirot. 



A point A at the centre of the plate is heated and one contact is 

 made on the other side of the plate, at the end of the line which 

 connects this point with A across the long grain, the other taken at 

 a point C on the end of the line joining the point A along the long 

 grain. 



In all cases a current was obtained from B to C. The strength 

 of the current for the same metal appeared connected with the 

 development of the long grain. Thus, that zinc which had passed 

 four times through the draw-plate gave a feebler current than zinc 

 which had been drawn out six times. But copper with a good 

 deal of long grain, that is much more fragile in one direction than 

 another, gave a feebler current than tin, which seemed to have no 

 appreciable grain. It must moreover be observed that this tin had 

 passed six times through the plate ; hence the thermoelectric action 

 shows the action of the draw-plate, even when the fracture does 

 not show it. 



