﻿of Phosphorus, Sulphur, and Aldehyde. 521 



velocity of the reaction occurs in this case at very nearly the 

 same pressure as that which van't Hoff found to be most 

 favourable to the reaction between phosphine and oxygen. 



In Table III. the values of K calculated from equation (2 b) 

 (in which the rate of reaction is put proportional to the pres- 

 sure) are also given. They are much less constant than the 

 values of K x . 



Sulphur and Oxygen. 



The course of this reaction is more regular than that of the 

 last, because the products of oxidation being volatile the surface 

 of the sulphur remains unchanged. 



The first experiments were made by a method similar to 

 that which was used with phosphorus, the volume being kept 

 constant and the pressure allowed to change. The essential 

 part of the apparatus is shown in fig. 4. It consisted of a 



Fig. 4. 



tube with two bulbs blown upon it, B, S, and of 60-70 cubic 

 centim. capacity. At S, 1-2 grams of pure sulphur, at B, 

 5-6 grams of soda-lime were placed, and the end C sealed up 

 before the blowpipe. The capillary-tube D connected the 

 apparatus with a manometer, and with the tap E, by means 

 of which it was filled with oxygen. The whole was heated 

 Phil. Mag. S. 5. Vol. 38. No. 235. Dec. 1894. 2 N 



