94 On avoiding Sal-ammoniac in Analysis. 
In conclusion, I think it may be truly said that one of the 
i of the most intimate physiological, microscopical stud- 
es of the present day, is to show the inadequacy of microscopic 
ae chemical investigations to detect physical differences in struc 
tures essentially dissimilar. Once appreciating this fully, we are 
prepared for the ulterior doctrine, that in organization, matter 1s 
but the vehicle for the phenomenal manifestation of determinate 
ideas, which last only, therefore, have an objective reality. 
a 
Art. XV.—A Method of getting rid of Sal-ammoniac in 
Analysis ; by Dr. J. Lawrence Smiru. 
Tuere is nothing in mineral analyses more embarrassing than 
the accumulation of sal-ammoniac towards the end of an analysis, 
especially where potash and soda are to be estimated. oul 
method now adopted to get rid of this ammoniacal salt, is to 
volatilize it by heat, which, if the quantity be considerable, 1s 
attended with no little annoyance, and a certain loss of more of 
less of the fixed alkalies which may be abeate I have. within 
the last twelve months discovered a met overcoming that 
difficulty, and much experience during that time has. proved 
that it is of considerable value. The method is simply to add 
nitric acid to the solution containing the sal-ammoniae and alka 
lies, and heat it gently over a lamp or sandbath in a glass flask or 
porcelain capsule. The nitric acid may be added either before 
the liquid is concentrated or after concentration ; a most quiet 
decomposition ensues, and the liquid readily evaporates to dryness 
leaving nothing but the fixed alkalies if they be present. [am 
in the habit of | using a little more than three grammes of pure 
nitric acid of ordinary strength to every gramme of sal-ammoniac 
supposed to be present in the liquid. The exact nature of the 
decomposition which ensues cannot now be stated, but there is 
doubtless formed besides other things—chlorine, hyponitrie 
and nitrogen. 1 shall not enter more into detail about this 
method, as [ intend at a future time to do this; only wishing a 
present to take precedent in what I presume a method of some 
importance in analytical chemistry and never to have been 
before for this end. ey 
