2 4 o SCIENCE PROGRESS. 



ordinary rule is not obeyed. Behal and Choay have deter- 

 mined the melting-points and boiling-points of a number of 

 phenols and their derivatives (60). 



As regards methods, V. Meyer, Riddle, and Lamb (61) 

 have improved the method of Meyer and Freyer for 

 determining the melting-points of salts. This method 

 involves the use of a platinum air-thermometer. The 

 platinum resistance-thermometer of Callender and Griffiths 

 has also been used by Heycock and Neville (62) to deter- 

 mine high-temperature melting-points, particularly those 

 of metals. So far as the results go these two methods give 

 fairly concordant values. The latter method especially 

 promises to be of considerable value in this field. For 

 rough work over the temperature range from 200° to 6oo° 

 or so, the thermometer described by Baly and Corley (63) 

 containing sodium-potassium alloy in place of mercury may 

 also be found of service, although as the alloy attacks the 

 glass the readings in time become troublesome to make. 



Heat of fusion. — The heats of fusion of a number of 

 organic compounds have been measured by Bruner (64). 

 The value for a brom-derivative is greater than that of a 

 chlor-derivative. As a general rule his numbers agree with 

 those deduced from observations on the freezing-point of 

 solutions by van't Hoff's formula, unless in the case of 

 palmitic acid (found 39/2, calc. 49*5) and o-naphthylamine 

 (found 22*3, calc. 26"3). 



Vapour-pressure of salts. — According to Bailey (65), 

 even at temperatures below the boiling-point a dissolved 

 salt has an appreciable vapour-pressure, and consequently 

 if a saline solution be evaporated, there is a small loss due 

 to volatilisation of the salt. Special pains were taken to 

 prevent the possibility of the salt being mechanically carried 

 over. The salts examined were chlorides of the alkalies, and 

 the loss was found to be greater the greater the molecular 

 weight and the stronger the solution. On evaporating a 

 litre of a solution containing 286 gr. of caesium chloride, 

 1 8 "86 mg. of salt were lost. 



Stoic hiometry of glass and crystals. — Winkelmann and 

 Schott (66) find that the physical properties of glass are 

 functions of its chemical composition, indeed their experiments 



