ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

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PHYSICS. — Specific heat of liquid ammonia. Nathan S. Osborne 

 and Milton S. Van Dusen. Bureau of Standards Scientific 

 Paper No. 313. Pp. 35. 1917. 



By use of a calorimeter of the aneroid type specially designed for 

 the peculiar conditions, the specific heat of saturated liquid ammonia 

 has been determined throughout the temperature interval —45° to 

 + 45°C. 



Two distinct and independent methods were used, each of which 

 avoids sources of error present in the other. The greatest difference 

 between the mean results of both methods and the results of either 

 method as represented by empirical equations is less than 1 part in 

 1000.. 



As a final result, the specific heat <r in joules per gram per degree 

 centigrade, of liquid ammonia, kept saturated, at the temperature d, 

 is given in the range —45° to +45°C. by the equation 



16.842 



(J - 3.1365 - 0.00057 6 + 



V 133 - ^ 



N. S. 0. 



PHYSICS. — The latent heat of pressure variation of liquid ammonia. 

 Nathan S. Osborne and Milton S. Van Dusen. Bureau of 

 Standards Scientific Paper No. 314. Pp. 51. 1917. 

 When a fluid undergoes a change of pressure, there occurs a trans- 

 formation of energy into heat or vice versa, which results in a change 

 of temperature of the substance unless a Hke amount of heat is ab- 

 stracted or added. This change expressed as the heat so transformed 

 per unit change of pressure will be called "latent heat of pressure varia- 

 tion." For most liquids under usual conditions of temperature and 

 pressure this quantity, which depends on the thermal expansivity, is 



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