684 REPORT — 1892, 



"With regard to these results it is to he noted that the ethers were obtained 

 from commercial samples by fractionation, and the composition has not yet been 

 checked by analysis or by determining the vapour density ; further, that, while in 

 the first series the value of OHo depends on two substances for each of the mem- 

 bers of the pair, that of 3(CH,) depends on one substance for one of the pair and 

 two for the other, and it is most probable that the ethyl formate is slightly acid, 

 and thus the molecular volume is too low, and the value of CH^ is too hio-h. 



We may also notice that, comparing the molecular volumes of each substance 

 in the three solvents, or their differences per CH.j, and including water— 



10. Report of the Committee on Isomeric Naphthalene Derivatives. 

 See Reports, p. 191. 



11. Report of the Committee on the Action of Light on Dijed Colours. 



See Reports, p. 263. 



12. On the Amount of Hydrolysis in Aqueous Solutions of Salts of Strong 

 Bases with WeaJi Acids. By Dr. J. Shields. 



The author has calculated the amount of free alkali in several salts from obser- 

 vations of the velocity of reaction on saponifying ethyl acetate by their solutions, 

 and finds that it is very nearly proportional to the square root of the concentration 

 of the salts. 



The actual quantity contained in A molecular normal solutions of the foUowiuo- 

 salts at 24°-2 C. is— " 



Potassium cyanide 1-12 per cent. 



Potassium jDhenate 3-05 



Sodium carbonate 3-17 



Boras (about) 0-5 ',' 



Sodium acetate 0-008 



Tri-sodium phosphate in /^ molecular normal solution was found to be almost 

 completely hydrolysed into di-sodium hydrogen phosphate and sodium hydrate. 



13. A new Method for Measuring the Pressure produced in Gaseous Explo- 

 sions. By Bevan Lean, B.A., B.Sc, Dalton Chemical Scholar of the 

 Owens College, and W. A. Bone, B.Sc, Fellow of Victoria University. 



The authors have devised a new method by which they liope to be able to 

 measure the pressure produced on the explosion of gaseous mixtures. All former 

 measurements involve the motion of a gauge of considerable mass. Bunsen 

 measured the pressure developed by studyuig the limiting weight raised by a 

 valve attached to a bomb. Berthelot and Vieille determined the rate of displace- 

 ment of a piston of known section and mass. Mallard and Le Chatelier have 

 employed a Deprez manometer, and also a metalUc Bourdon gauge. Dugald Clerk 

 has made use of a Ilichards indicator. In consequence of the instantaneous 

 character of gaseous explosions it is doubtful whether, by the means employed by 

 these experimenters, it is possible to measure the real pressure produced by the 

 explosion. Their methods would appear to measure no more than the effective 

 pressure. 



The authors give preliminary experiments in which they have studied the 

 pressure produced by the explosion of a mixture of two volumes of hydrogen with 

 one volume of oxygen. 



