August 23, 1907] 



SCIENCE 



239 



salts ; metathetical reactions ; oxidation and 

 reduction cells. The method of calculating 

 chemical affinity from the equation for 

 equilibrium has then been applied to the 

 cases in which electromotive force measure- 

 ments are impossible or inaccurate. 



There is no way at present to measure 

 chemical affinity in the case of an appar- 

 ently irreversible reaction, in other words, 

 in the overwhelming majority of instances. 

 It is suggested that the best line of attack 

 is the study of the electromotive forces of 

 irreversible cells made up of oxidizing and 

 reducing agents. 



The Stable Hydrates and Acid Salts of 



Ferrous Sulphate: Feank B. Kenrick, 



University of Toronto. 



The object of the experiments was to 

 determine the composition of the ferrous 

 sulphates stable at ordinary temperatures 

 in systems containing the components FeO, 

 SO3 and HjO. Mixtures of varying propor- 

 tions of these components together with a 

 little ammonium sulphate were shaken until 

 equilibrium was reached, and the liquid 

 and moist solid phases analyzed. From 

 these results the composition of the solid 

 phase was calculated, the amount of liquid 

 adhering to the solid being determined 

 from the quantity of ammonium found. 



The existence of the following chemical 

 individuals, besides the ordinary green vit- 

 riol, has been proved with a fair degree of 

 certainty : FeO • SO3 ■ 4H2O, FeO • SO3 ■ H^O, 

 2FeO-3S03-2H20, FeO^SOg-H^O and 

 FeO^SOj-SH^O. 



The Mechanism of the Acetacetic Ester 

 Synthesis: W. Lash Miller, University 

 of Toronto. 



The rates of the condensation of oxalic 

 ester with acetone and with ethyl acetate 

 have been measured by Mr. Clark and Mr. 

 Cooke, the progress of the reactions being 

 determined by colorimetric measurements 



after adding ferric chloride. Some inter- 

 esting features of the behavior of the red 

 coloring matter have been studied inciden- 

 tally. 



Mutual Solubility of the Chlorides of Cal- 

 cium and Sodium: W. 0. Robinson, Bu- 

 reau of Soils, Washington. 

 The complete isotherm of the system cal- 

 cium chloride, sodium chloride and water 

 at 25° has been determined. The solubility 

 of calcium chloride hexahydrate is very 

 greatly depressed by sodium chloride. The 

 "constant solution" contains 78.49 grams 

 calcium chloride and 1.846 grams sodium 

 chloride to 100 grams of water. The hexa- 

 hydrate of calcium chloride inverts to the 

 tetrahydrate, in presence of an excess of 

 sodium chloride at 29°. 



The Measurement of the Vapor Pressure of 

 Solutions with the Morley-Brush Gauge: 

 0. F. Tower, Adelbert College, Cleve- 

 land. 



The method is a differential one. The 

 gauge was described, and the results of 

 measurements with solutions of potassium 

 chloride and cane sugar were given. The 

 paper was of a preliminary nature. 



Absorption of Water Vapor by Soils: F. 

 E. Gallahgee and H. E. Patten, Bu- 

 reau of Soils, Washington. 

 The absorption of water vapor by quartz 

 flour, a soil separate, and typical soils, has 

 been studied with special reference to the 

 controlling conditions. The rate of ap- 

 proach to equilibrium between soil and 

 water vapor has been followed at various 

 degrees of humidity, and these equilibrium 

 points determined. The amount of water 

 absorbed increases with the humidity, but 

 not in a simple mathematical relation. The 

 equilibria between soils and atmospheres 

 saturated with water vapor were studied 

 over a temperature range from 25° C. to 

 100° C, and, contrary to Hilgard's results. 



