626 SCIENTIFIC KECORD FOR 1885. 



mulas. The society was asked to appoint a committee to take this sub- 

 ject into consideration and to act with a similar committee already ap- 

 pointed by the Soci^te Internationale des Elecrriciens. (Proc. Soc. Teleg, 

 Eng. and Elec, xiv, 297 ; Nature. June, 1885, xxxii, 184.) 



The British Association committee on electrical standards reported 

 at the Aberdeen meeting, through the secretary, that they had had con- 

 structed a series of coils to serve as standards in terms of the legal 

 (Paris) ohm, assuming this ohm to be 1-0112 B. A. unit. These stand- 

 ards, ten in number, had been carefully compared with each other, by 

 the methods already described in reports of the committee, and also 

 with mercury tube resistances prepared by Benoit, of Paris. The legal 

 ohm standards as constructed by the committee exceed those constructed 

 in Paris by 0-00049 legal ohm. Standards of electro-motive force and of 

 capacity should also be issued by the committee, in their opinion. (Na- 

 ture^ October, 1885, xxxii, 528.) 



Klemencic has determined the ratio between the electro-static and 

 the electro-magnetic systems of units by the following method : The 

 current of a battery of 9 to 15 Dauiell cells is made to charge a condenser 

 which is then discharged through the wire of a galvanometer. The per- 

 manent de^datiou Avhich results from these continuous discharges is 

 noted, as well as the arc of impulsion of the galvanometer under the in- 

 fluence of the direct current from the battery. The capacity of the con- 

 denser is then calculated in electro-magnetic measure. The value in 

 electro-static measure is deduced from the theory of Kirchhoff. In other 

 experiments the battery charges the condenser, and at the same time 

 acts upon a diflereutial galvanometer through one of its coils placed in 

 shunt circuit. The discharge of the condenser traverses the second 

 wire and the resistances are so regulated that there is no deviation. 

 The author gives as the value of the constant v of Maxwell, 3-0188 x 

 1010 cm. sec. {Ber. Al\ ^¥^en., 1884, 88; J. Pliys., April, 1885, II, iv, 183.) 



Fletcher has determined the value of the B. A. unit of resistance in 

 terms of the mechanical equivalent of heat, and has obtained the value 

 0*9904 earth quadrants per second. The method consisted in simul- 

 taneous thermal and electrical observations of the energy expended 

 by an electrical current in a coil of wire immersed in a calorimeter. 

 {Am. J. Scl, July, 1885, III, xxx, 22.) 



Himstedt has published the results of his determination of the ohm 

 made by a method suggested by him in 1884. The constant deviations 

 of a magnetic needle in the same galvanometer, produced in the one 

 case by means of induction currents j)assing in the same direction 

 through the galvanometer at the rate of n per second, and in the other 

 by means of a constant current whose strength is a known fraction ot 

 the inducing current, are carefully observed, and from the data thus 

 obtained the resistance can be calculated. The lowest value obtained 

 for the resistance of tbe Siemens unit was 0-94323 and the highest 

 0-94380 ohm, the uiean l)eing 0-94356 ohm. Hence 1 ohm is equiva- 



