372 H. Wurtz’ Contributions to Analytical Chemistry. 
append, without my knowledge, a note to Dr. Smith’s paper, 
which reads as follows. ' 
‘* Note to Dr. Smith’s paper on the decomposition of the chlorids by 
nitric acid.—Dr. Smith’s observation that the alkaline chlorids 
are decomposed by heating and evaporating with nitric acid is 
not new, although I am not aware that the fact has ever been 
published. Mr. H. Wurtz made experiments on the subject in 
my laboratory two years since, and obtained the same results as 
Dr. Smith. The complete decomposition of chlorid of magne- 
sium by evaporation with nitric acid, was also observed in the 
laboratory of the late Prof. Norton, a year or two I believe before 
Mr, Wurtz studied the subject. The alkaline nitrates are easily 
converted into chlorids, by boiling them with an excess of chlor- 
hydric acid, in presence of any metallic oxyd having a strong 
affinity for oxygen. I employ the protochlorid of tin for this 
purpose, and when the reaction is over, and gas (nitrous oxyd) 
is no longer evolved, a current of sulphydric acid gas removes 
the tin, and the filtrate contains only the alkaline chlorid and 
free chlorhydric acid.—w. a.’”* ee 
I have introduced the italics for the purpose of directing 
attention to what is apparently a misremembrance of date on 
the part of Dr. Gibbs; my experiments in his laboratory having 
been made, as above stated, about three years and a half prevr 
ously, and so far as I can ascertain, no experiments having been 
made in Professor Norton’s laboratory. Although the matter 18 
of no great importance, it still seems right that the discovery ‘ 
the complete decomposition of chlorid of magnesium by mitn¢ 
acid, which was the starting point of the following investigation, 
and which appears to have been first made by me, should not g° 
without a claimant. sa 
sent 
the results of my experiments, the object of which has ype 
ascertain the character of the action of nitric acid 7 all the 
owledge 
* Am. Jour. Science [2], xvi, 416. 4 
+ It would be wrong for me not to acknowledge here my indebteduess (0 OR. 
of my friends, especially to Messrs T. Sterry Hunt, George J. Brush an h 
rant, for ery generous manner in which they have supplied me wit ——p. W- 
tions of rome of the rare metals, needed to render my investigation complete’ 
