J. L. Smith on determining the Alkalies in Minerals. 241 
- 25.-The manner of proceeding is as follows. To the filtrate 
and washings concentrated in the way mentioned (22) and still 
temaining in the flask, pure nitric acid is added—about three 
grammes of it to every gramme of sal-ammoniac supposed to 
exist in the liquid; a little habit will suffice to guide one in add- 
lng the nitric acid, as even a large excess has no effect on the 
accuracy of the analysis. 
26. The flask is now warmed very gently, and before it reaches 
the boiling point of water, a gaseous decomposition will take 
place with great rapidity. This is caused by the decomposition 
of-the sal-ammoniac in the manner described in the note. — It is 
ho advantage to push the decomposition with too great rapidity ; 
@moderately warm place on the sand-bath is best adapted for this 
Purpose. With proper precautions the heat can be continued 
nd the contents of the flask evaporated to dryness in that ves- 
sel 5 but it is more judicious to pour the contents of the flask, 
sand-bath oroveralamp. I prefer the latter, as at the end of 
the operation the heat can be increased to four or five hundred 
27. By this operation, which requires no superintendence, one 
hundred grammes of sal-ammoniac might be separated as easily 
and safely as- one gramme from five milligrammes of alkalies, 
tnd no loss of the latter be experienced, hat remains in the 
“apsule occupies a very small bulk; this is now dissolved in the 
VSR a ay 
_ ‘be almost entirely absorbed by the water. What remained was a mixture 
Soe eee and a little air, some nitrous or hyponitrous acid forms during the whole 
: » if ieee nitric be used; if, however, hea diluted, little or none is 
and the gas is readily given off at about 212° Fah. : 
iments, hs eotoxed of nitrogen constituted from seven-eighths to 
the wh its chlo- 
t of the decomposition which takes place, 1s. j 
of af 1°, At first, I supposed that, the decomposition resulted in the formation 
that tt volumes of NO, rh and N, but it appears that such is not the case, and 
all ry small ion of the ammonia cpt its equivalent of nitric = 
ie aci itric 
¢ acid, does undergo the decomposition 
ean mall amounts of chlorine and nitrogen 
At the time this method was first tried, I also tried the decom- 
j moniac, that has been shown by Mau- 
sult in the formation of chess and 
4; Dut the difficulty of controlling the decomposition once commenced, the 
Tender up of the pevanaan Pa the necessity of Saving the salts dry to begin with, 
in Pensa d (which was proposed by the author for forming ) useless 
~* esses for removing the sal-ammoniac in analysis. 
