SILVER, POTASSIUM, ETC. 35 



All the successors of Berzelius in this work have benefited by his exam- 

 ple, although for the methods by which loss has been prevented we must 

 refer to the original pai)ers of the several investigators. In short, then, 

 Berzelius ignited potassium chlorate, and determined the percentage of 

 chloride which remained. Four experiments gave the following results : 



60.854 

 60.850 

 60.850 

 60.851 



Mean, 60.851, =h .0006 



The next series Avas made by Penny,* in England, who worked after 

 a somewhat different method. He treated potassium chlorate with 

 strong hydrochloric acid in a weighed flask, evaporated to dryness over 

 a sand bath, and then found the weight of the chloride thus obtained. 

 His results are as follows, in six trials : 



60.825 

 60 822 

 60.815 

 60.S20 

 60.823 

 60.S30 



Mean, 60.8225, ± .0014 



In 1842 Pelouzet made three estimations by the ignition of the chlo- 

 rate, with these results : 



60.843 

 60.S57 

 60.830 



Mean, 60.843, d= -0053 



Marignac, in i842,:|: Avorked with several different recrystallizations of 

 the commercial chlorate. He ignited the salt, Avith the usual precau- 

 tions for collecting the material carried off mechanically, and also exam- 

 ined the gas Avhich Avas evolved. He found that the oxygen from 50 

 grammes of chlorate contained chlorine enough to form .003 gramme of 

 • silver chloride. Here are the percentages found by Marignac : 



In chlorate once crystallized 60.845 



In chlorate once crystallized 60.835 



In chlorate twice crystallized 60.833 



In chlorate twice crystallized 60.844 



111 chlorate three times crystallized 60.839 



In chlorate four times crystallized 60.839 



Mean, 60.8392, zt .0013 



* Phil. Transactions, 1839, p. 20. 



tCotnpt. Rend., 15,959. 



X Ann. d. Chem. u. Pharm., 44, 18. 



