Physics and Chemistry. 151 



BuNSEisr. The process depends upon the condensation of steam 

 upon the solid under examination, when the latter is immersed in 

 steam. The difficulties of weighing the water of condensation have 

 been completely obviated by suspending the substance in a small 

 platinum basket, with fine meshes, in steam and weighing it without 

 withdrawing it from the steam. The ingenious and simple appa- 

 ratus by means of which this is accomplished is figured in the 

 author's paper. The simple formula, in which all the quantities 

 can be determined with great exactness is as follows : 



G u L = 6 K G K (t-t) + S p G p (t-t). 

 Where G u is the weight of the condensed water, L the latent 

 heat of the steam at temperature t v G K the weight of the body, 

 and t its temperature, 8 K its specific heat, G„ the weight of the 

 platinum basket, 6 p its specific heat (by suitable modification 

 of the formula, the specific heat of a liquid can also be obtained). 

 — Ann. der Physik and Chemie, No. 5, 1887, pp. 1-14. j. t. 



4. JElectriccd Resistance of Antimony and Cobalt in a Mag- 

 netic field. — Dr. G. Fae experiments show that when antimony 

 is brought into a magnetic field its electrical resistance increases 

 both across and along the lines of magnetic force. Cobalt shows 

 a diminution of resistance in a plane, perpendicular to the line of 

 force, and an increase in the direction parallel to them. — Phil. 

 Mag., June, 1887, p. 540. J. t. 



5. Effect of Electricity on Dust. — R. Nahrwold shows that 

 electrical charges escaping from fine points electrify the pai'ticles 

 of dust or vapor in the air and not. the air itself; also that glow- 

 ing platinum wfres throw off particles which make air a conductor 

 (previously observed). The author believes that air and gases 

 freed from dust can not be statically electrified. He also con- 

 firms the statement that negative electrical charges escape from 

 points more readily than positive ones. — Ann. der Physik und 

 Chemie, pp. 448-473, No. 7, 1887. J. t. 



6. The Hall Effect. — A. Voisr Ettinghattsen and W. Nernst 

 have lately examined the Hall effect in different metals. They 

 discovered that the effect is far greater in tellurium than in bis- 

 muth and they are led to think that the effect is connected with 

 the thermo-electrical properties of the metals — the effect is least 

 in tin. Taking the effect in tin as unity, the effect in the other 

 metals examined are as follows: 



Platinum 6 



Copper £ 13 



Gold 28 



Silver 21 



Palladium 29 



Cobalt , 115 



Iron 285 



Nickel 605 



Carbon 4,400 



AntimoDy 4,800 



Bismuth 252,500 



Tellurium 13,250,000 



