256 



SCIENCE. 



[X. S. Vol. XXI. No. 529. 



uot liithorto been carefully controlled, al- 

 though they affect the yield very materi- 

 ally. 



The Efficiency of Ceittrifiujal Purifjcaiion : 

 T. W. Richards. 



The very great gain in time, labor and 

 material effected by centrifugal draining 

 and washing during the purification of 

 crystals was demonstrated by quantitative 

 experiments, and simple forms of appa- 

 ratus were suggested which secure these 

 advantages to the organic chemist or to the 

 worker with small quantities of precious 

 material. 



Electro-stcnolysis and Faraday's Law: 

 T. W. Richards and B. S. Lacy. 

 It was demonstrated by quantitative ex- 

 periments that the deposition of large 

 quantities of silver electro-stenolytically in 

 the middle of an electrolytic cell had no 

 effect on the weight of the deposit of silver 

 at the cathode, and, therefore, that Fara- 

 day's law still holds true under these 

 peculiar conditions. This is of interest in 

 its relation to the porous cup eoulometer, 

 although it is true that no electro-stenolytic 

 deposits are observed on the cup under 

 ordinary conditions. 



These two papers will appear in the 

 Journal of the society. 



The Mercury Sulphocyanate Complexes: 

 ]M. S. Sherrill and S. Skowronski. 

 The paper is published in full in the 



January, 1905, number of the Journal of 



the society. 



The Solubility of Calcium Sulphate in 

 Solutions of Ammonium Salts and of 

 Certain other S(dts: F. K. Cameron and 

 B. E. BRcmN. 



It is shown that the solubility curve for 

 calcium sulphate-ammonium chloride has 

 a maximum value corresponding to about 

 22.5 grams of the more soluble salt per liter, 

 and about 10.9 grams per liter of calcium 

 sulphate. From this point on, with in- 



creasing concentration of annnonium chlo- 

 ride, the solubility of calcium sulphate de- 

 creases, until in a saturated solution there 

 is only 7.4 grams per liter calcium sulphate. 

 The ammonium nitrate curve is similar to 

 the annnonium chloride curve, the solu- 

 bility being somewhat higher. Here again, 

 with high concentrations with respect to 

 the more soluble salts the solubility de- 

 creases until in a saturated solution of am- 

 monium nitrate it is only about half as 

 soluble as it is at the maximum point. 



The authors give the data they obtained 

 with a concentration of the solution with 

 respect to calcium sulphate and other more 

 soluble salts, such as the chlorides, nitrates 

 and sulphates of sodium, magnesium and 

 ammonium. 



llie Action of Water upon Calcium Phos- 

 phates: F. K. Cameron and A. Seidell. 

 (Read by title.) 



Tlie Action of Solutions of Potassium 

 ^titrate upon Tricalcium Sulphate: F. K. 

 Cameron and J. G. Smith. 

 The authors studied the action of solu- 

 tions of various concentrations with respect 

 to potassium nitrate vipon tri-calcium phos- 

 phate at a temperature of 20°, for various 

 lengths of time and for various proportions 

 of solid to solution. It was shown that 

 increasing the concentration of potassium 

 nitrate increased both the phosphoric acid 

 and the calcium going- into solution, but 

 that the ratio of calcium to phosphoric acid 

 steadily decreases until in saturated solu- 

 tions of potassium nitrate the ratio is ap- 

 proximately that required by the formula 

 of tri-calcium phosphate. It appears, 

 therefore, that increasing the amount of 

 potassium nitrate in the solution reduces 

 the hydrolizing action of water, although 

 the solubility of the substance steadily in- 

 creases. 



Molecular Attraction : J. E. ]\Iills. 



The article was a summary of work 



