Chemistry and Physics. 



3 is used. The apparatus consists of a brass cylinder S( 

 enclosed in a second concentric 



iiider. The top of the inner cylinder may be unscrewed and 

 ir tarries a conical cavity in which is placed a rubber cork 

 Avitli a hole through it. A glass tube passes through this hole 

 and a metallic cap screwed on below the rubber presses it against 

 the glass. A similar closure carries the tube through the outer 

 cylinder. The latter is connected with a mercury pump. A com- 

 parison of the time and variations of the pressure when the outer 

 cylinder was immersed in ice-water gave the following coefficients 

 of conductibility : 



Name. Conduct. 



Air -0000525 



Hydrogen -0003324 



Carbonic Acid -0000317 



Ethvl -0000414 



Marsh Gas ..-0000647 



Nitric Oxide -0000460 



Carbonic Oxide -00005 10 



Oxygen -0000563 



Nitrous Oxide -0000363 



Nitrogen -0000524 



—Pogg. Ann. clvi, 497. e. c. p. 



7. ITiermal Properties of Liquids. — M. Pictet has applied the 

 mechanical theory of heat to the study of volatile liquids, mak- 

 ing use of the experiments of Regnault. and deduces the following 

 simple relations between their latent heats, atomic weight and va- 

 il.) The cohesion of all liquids is constant. 



(2.) The diiferential coefficient of the Naperian logarithm of 

 the tension divided by the temperature is constant for all liquids 

 when referred to the same pressure and temperature. 



(3.) The latent heat of all liquids referred to tiie same pres- 

 sure, multiplied by the atomic weight referred to the same tem- 

 perature, gives a constant product.^ 



(4.) For all liquids the difference of the internal latent heats at 

 any two temperatures, multiplied by the atomic weight is a con- 

 It thus appears that quantities at first sight wholly independent 

 are really connected by verv simple relations, which dispense with 

 long empirical formulas based on observations more or less open 

 to criticism. 



Furthennore, admitting the law of Dulong and Petit for specific 

 heats, we can further say that the latent heat of all liquids are 

 multiples of their specific heats.— 7?/W. Univ., ccxvii, 66. 



8. Dependence of Electrical Resistaitce on the Motion of the 

 Conductor. — M, Edlu.nd has brought to bear a new argument in 



"* 'i '"nductor is affected by its motion. Water is allowed to 



