1815.] On Mine. .405 



Oxygen 22'59 



loduret of potassium 77*41 



100-00 



But from the composition of ioduret of zinc given above, 

 namely, iodine 100, zinc 26-225, and admitting, according to my 

 experiments, tliat 100 zinc combine with 24-41 oxygen, and ac- 

 cording to Berzelius, that ICO potassium unite with 20-425 oxygen 

 in order to be converted into potash, we find that ioduret of potas- 

 sium is composed of 



Iodine 100 



Potassium 3 1*342 



According to this proportion, the 77*41 of ioduret of potassium 

 are composed of 



Iodine 58-937 



Potassium 18*473 



77-410 



The 18*473 potassium take 3-773 oxygen to be converted into 

 potash. There remain, then, 22-59 — 3*773 = 18-817 to acidify 

 the iodine ; so that iodic acid is composed of 



Iodine 100 



Oxygen 3 1*927 



Tlie ratio of oxygen to iodine is, then, 10 to 31*321. If we 

 multiply this last number by 5, we have the ratio 10 to 156-G05, 

 which difters but little from the ratio formerly obtained, 10 to 

 15(j*21, from the hydriodate of zinc. 



If we convert the iodine and oxygen into volumes, we find that 

 iodic acid is composed of 



Iodine 1 



Oxygen 2*5 



It is now easy to determine how much ioduret of potassium we 

 ought to obtain, relatively to the iodate of potash which is formed 

 at the same time, when iodine is dissolved in potash. Since 100 

 iodate of potash contain 22-59 oxygen, of vvhitli 3*773 belong to 

 tlie potash, it is evident that the renjaiudcr 18817 which belong to 

 tlie iodine has been furnished eitiier by the potash, which after 

 giving it out has formed ioduret of potassium, or, which comes to 

 the same thing, by the water the hydrogen of which formed 

 iiydriodate of potasli ; but 18-817 oxygen correspond with 92-127 

 potassium, and tiiis last with 293-9IO iodine. Therefore, for every 

 100 of iodate of potash there are formed 38(>()(>7 of ioduret of 

 potassium ; that is to say, live times as much as the iodate would 

 give by its decomposition. Tiiis ratio may be deduced immediately 



