344 P. Collier on Indirect Determinations of Potash and Soda, 
of the highest hill of the Mount Desert group, an elevation of 
2000 feet, its action for ages might have indeed accomplished 
the rounding and sloping of the northern sides of those moun- 
tains; but the ice of a few hundred feet in thickness above their 
summits, could not have produced that vast amount of denuda- 
tion required to form their southern brows. It is altogether 
probable that the glacier far overtopped the highest of the hills, 
and it is not unreasonable to suppose it to have been at least 
twice two thousand feet in thickness. . 
Moreover there is evidence that this glacier was not limited to 
this great fiord of Maine. It must have extended far toward 
the east and covered the country on the west. In fact, it was 
probably a part of the universal glacier which covered the con- 
tinent wherever the drift striae have been observed. But upon 
the discussion of this point I will not now enter. 
Art. XXX.— Contributions from the Sheffield Laboratory of Yale 
Coliege. No. VIIL—On the Indirect Determination of Potash and 
a; by Perer Conner, B.A., Assistant in the Sheffield 
Laboratory. , 
dence of chemists, at least, it is rarely mentioned in published 
investigations. I have therefore, at the suggestion of Prof. John 
son, made a number of experiments to ascertain the limits of 
error in this process, 
he volumetric estimation of chlorine as perfected by Mohr 
offers by far the best basis for an indirect determination of t 
alkalies. It is in fact requisite in employing the usual direct 
method, to procure the alkalies in the condition of pure chlorids 
before precipitation. . 
hen the alkali chlorids are obtained free from all foreig? 
matters, it is but the work of a few moments to ascertain their 
content of chlorine. 
_ The silver solution used for this purpose is best prepared by 
weighing off in a porcelain crucible about 4:8 grm. of clean hi’ 
tallized nitrate of silver, fusing it at the lowest possible. t 
and then ascertaining its weight accurately. After fusion © 
ould weigh a little more than 4:7933 grm., the quantity Bee 
contained in a liter of water, gives a solution of which.1 ¢. & es 
® 
