ON THE ESTIMATION Ol' fOTASH AND THOSI'IIOIUC AC1U. 



21 



Tlic next experiments were made to ascertain the effect of employing 

 hydrochloric acid in place of chloride of sodium, according to the reaction 

 K>.0 4 + 2HC1 + PtCl 4 =E 2 PtCl + U,K0 4 . 



In Experiments 71, 72, and 73, 2 cub. ccntims. of hydrochloric acid were 

 employed ; in Experiments 74 and 7-3, 2| cub. centime, were used. The 

 acid in each case had a density of I'll. 



Table X. 



In the first three experiments the quantity of HC1 appears to have been 

 insufficient to effect complete conversion, but in tho latter experiments the 

 reaction seems to have been more perfect. 



The following experiments Avere made in illustration of the use of Tatlock's 

 process in tho analysis of a German niuriate, which was represented by a 

 mixture containing 85 per cent. KC'l, 10 per cent. MgS0 4 (anhydrous), and 

 5 per cent. NaCl. 



Table XI. 



A mixture containing 50 per cent. KC1, 25 per cent. XaC'l, and 25 per cent. 

 ilgSO, was found by Mr. Galbraith to contain 99-83 per cent, of KC1 for 

 100 introduced, equal to 49-915 per cent, in the actual sample. 



In many of the experiments detailed it must be remembered that the 

 actual departure from the truth is only a fraction of what it appears to bo 

 on calculation to 100 parts. Thus in the above Tables the results are com- 

 pared -with 100 parts of the potassium salt taken, whereas in practice tho 

 results would be stated on 100 parts of the sample. Hence in a mixture of 

 equal parts of the chlorides of potassium and sodium, to obtain 100-5 parts 

 of KC1 instead of 100 would be expressed in practice by stating the sample 

 to contain 50-25 of KC1 and 49-75 of Nad, thus reducing the actual error 

 to half what it appears to bo in some of the Tables. This view finds expres- 

 sion in Table V. 



The next experiments were made by Tatlock's method on pure nitrate of 

 potassium, to which was added enough chloride of sodium (-42 grm.) for tho 

 reaction — 



2KNO a + 2NaC'l + rtC'l 1 = X j PtC , l ( + 2NaNO,. 



