408 



Mr. W. H. Pendlebury and Miss M. Seward. 



and v = 20) the rate in the second case is about twelve times that 

 in the former. 



We have however proved by trial that chloric acid of itself, with- 

 out hydrochloric acid, when mixed in the cylinder with the other in- 

 gredients, will evolve oxidising material. The rate is exceedingly 

 slow : 



HC1 = 0. 

 HC10 3 = 6x51-5. 



Temp. = 20. 



Bate = 0-000000564. 



It is possible that two reactions are going on at the same time, one 

 with chloric acid alone, the other substances present having merely 

 their specific effect, and also the action between chloric acid and 

 hydrochloric acid, both producing oxidising material. 



Now amongst the various attempts made to find empirically the 

 law of connexion between variation of hydrochloric acid and varia- 

 tion of rate, one result arrived at was that second differences of the 

 rates are approximately constant. Especially is this noticeable for 

 smaller quantities of acid. The first differences thus resemble an 

 arithmetical progression. The next table consists of the same rates as 

 in Table IV, compared with a series of numbers obtained by recalcu- 

 lation after substituting for the first differences' of these a true 

 arithmetical progression, being the one they most nearly approach. 

 The constant difference in this case would be 0'000095. Beginning 

 from v = 11, we get the following results : 



Table IV6. 



From v = 10 to v = 17, the empirical numbers correspond fairly 

 with the observed rates, but afterwards the latter increase more 



