66 Scientific Intelligence. 



tion T log p'=— i(/>+<r) + (log ^ + (p+o-/2T ))T, cuts the 

 former one at a point corresponding to the temperature of fusion. 

 The author has calculated the heat of fusion of paratoluidine by 

 this formula from its solubility in water and finds it to be 44*5 

 calories per gram, while the value directly determined is 39 

 calories. From the solubility of water in ether, he obtains for 

 the heat of fusion of ice 154 calories ; whereas it is in fact only 

 80. But this result is based on the assumption that the molecule 

 of the dissolved water is H 2 ; so that if it be H 4 2 , the calcu- 

 lated value will become 77, which not only agrees quite well, but 

 is in accord with the statement of Eykman that only half the 

 normal depression of the freezing point is observed when water 

 is dissolved in liquid paratoluidine. — Zeitschr. physikal. Chem. y 

 v, 193 ; J. Chem. Soc, lviii, 686, July, 1890. g. f. b. 



3. On the Relation of Cupric chloride solutions to Heat. — 

 From thermo-dynamical considerations it follows, as Le Chatelier 

 and Yan't Hoff have pointed out, that when the heat of solution 

 of a substance in its almost saturated solution is negative, the 

 solubility will increase with rise of temperature; while when it 

 is positive the reverse will be the case. Reicher and van" De- 

 venter have tested this conclusion for cupric chloride CuCl 2 

 . (H 2 0) 2 ; one of the few salts which dissolve in much water with 

 evolution of heat, its temperature-coefficient of solubility being 

 positive. Consequently a remarkable behavior should be ob- 

 served with this salt with respect to the heat of solution in 

 liquids of different concentration. The authors find as theory 

 predicts, that in a saturated solution the heat of solution is nega- 

 tive. From thermochemical data given by Thomsen on the heat 

 of dilution of solutions of cupric chloride joined to data of their 

 own, the authors calculated that at 11° the heat of solution 

 attains a maximum when the solvent has a strength of about 

 8 molecules of CuCl 2 . (H 2 0) 2 to 198 molecules of water. At this 

 concentration, therefore, the salt would be dissolved without any 

 thermal effect whatever; and this, experiment shows to be the 

 fact. When the concentration is about 18 molecules of the salt 

 to 198 molecules of water, the heat of solution becomes negative. 

 Zeitschr. physikal Chem., v, 559; J. Chem. Soc, lviii, 1206, Nov., 

 1890. G. F. B. 



4. On the Seat of Combustion of Nitrogenous Animal Pro- 

 ducts. — By means of the calorimetric bomb, Beethelot and 

 Andre have determined the heat of combustion of the chief 

 nitrogenous constituents of animal tissues, the results of which 

 determinations are given in the following table. In this table 

 column 1 gives the value in water-gram-degrees for one gram of 

 the substance at constant pressure, column 2 the value for the 

 quantity of material containing one gram of carbon, column 3 

 the heat of combustion of one gram if the nitrogen is eliminated 

 in the form of urea and column 4 the value for the quantity con- 

 taining one gram of carbon, the nitrogen being eliminated as 

 urea. 



