438 F. H. Storer—Ammonia a contaminant of Sulphuric Acid. 
This last section of my Memoir, which purported at the out- 
set to treat of the amount of depression of the land during the 
melting of the glacier, has turned largely into a discussion of 
the evidences and effects of the Glacial flood—the subject of 
the first section. This is a consequence of the fact that the 
extent of the upper valley-terraces afford stronger testimony to 
the flood than the material of the beds, enabling us even to 
deduce the depth and spread and pitch of the flowing waters 
through the New England valleys, large and small. 
In another paper I propose to present other facts on this and 
connected topics derived from Long Island and the associated 
lands off the Southern New England coast. 
Art. LUI—Ammonia a constant contaminant of Sulphuric Acid s 
ry F. H. Srorer, Professor of Agricultural Chemistry in 
arvard University. 
the ordinary process of making sulphuric acid, and that it 
might remain as a contamination in the acid as used in the 
chemical arts. Acting upon the idea I have myself tested and 
have caused to be tested carefully and methodically a consider: 
able number of samples of sulphuric acid obtained from dif- 
ferent chemical works, and have found that every one of the 
specimens examined contained appreciable quantities of ammo- 
nia. nd, moreover, on looking the matter up, that the 
observation is not new, inasmuch as Schcenbein* has stated, so 
long ago as 1862, that he found traces of ammonia in all the 
samples of oil of vitriol which he had tested for that substance. 
My experiments would nevertheless seem to be worthy of pu 
lication, both because they confirm Schcenbein’s statement and 
because they go to show that ammonia is far more generally 
distributed as an impurity of chemical substances than has been 
commonly supposed hitherto. a 
The following acids were examined quantitatively by distill- 
ing a small portion of each of them wit ilk o lume, free 
_ from ammonia, and applying Nessler’s reagent to the distillate, 
in the manner described by Wanklyn, in his “ Water- Analysis, 
lon, 1874. ‘ 
I Oil of vitriol from a carboy bought at Bay-Side Alkali 
n. 
2 th 
IL Oil of vitriol from the Chemical Works at North Billerica, Mass. 
: * Wagner's Jahresbericht Chem. Technologie, viii, 266. 
