[miller-kenrick] researches IN PHYSICAL CHEMISTRY 211 



This method has been applied hitherto only where both solvents were 

 chemical compounds; as ether, water; chloroform, water, etc. It is, 

 however, equally applicable when one or both of them is a solution; 

 so that a good set of distribution measurements would show the effect 

 of the percentage of ether, say, in an ether-benzene solution on the 

 polymerization or dissociation of acetic acid etc., dissolved in the solu- 

 tion of ether and benzene. Mr. Eastlake's measurements established 

 the feasibility of the method, but were interrrupted before a complete 

 set of data had been obtained. (Winter 1910). 



No. 10. H. A. G. Willoughby: — The sulphates of calcium. The 

 sulphates of calcium stable at ordinary temperature in contact with 

 sulphuiic acid solutions of various concentrations were investigated 

 by a method similar to that used with the farrous sulphates (see Frank 

 B. Kenrick, above), partial separation of the solid phases being effected 

 by centrifuging through a loosely fitting glass valve in a tube closed 

 by a ground-glass stoppei". The extreme slowness with which equi- 

 librium was established made a complete investigation impossible, 

 and renders some of the results somewhat doubtful. 



The following compounds were identified: — 



CaSO^'. — stable with solutions containing less acid than corresponds 

 to the formula SO3 :2 • 1 H.p. The crystals were very minute, and the 

 consequent difficulty in separating them from the viscous mother- 

 liquor made the determination of an upper limit of the acid concen- 

 tration unreliable. 



2CaS0^.H^S0^. — consists of coarse irregular granules, some of which 

 appeared to be fragments of rhombic plates. It exists with liquids 

 ranging from about S03:H20 to 803:2-1 HjO. 



CaSO^-H^SO^ (?) : — Observed under the microscope in a drop of the 

 mother-liquor, this substance appeared as irregular granules inter- 

 mixed with small prisms, probably triangular in section. Exposed 

 to the air it changes to a mass of very fine granules. Its range of 

 existence is practically that of the 2CaSO^'H2SOi. No conclusive 

 evidence was obtained as to which of these two is the stabler form. 



CaSO^'^H^SO^. — ^This was not obtained pure, but was observed as 

 fairly large transparent crystals mixed with a fine-grained paste of 

 extremely fine granules in an acid of approximately the composition 

 SO3: 0*94 HjO. Some of these crystals were picked out and analy- 

 zed, giving results pointing to the formula assigned; they retain 

 their transparency for some minutes when exposed to the air, and then 

 slowly disintegrate into fine granules. 



The solubility of these calcium sulphates in the acid liquids was 

 in every case small, but increased with increase in the concentration 

 of the acid. The highest value olstained was for a lifjuid in equilibrium 



