290 American Geologist. ^^y- ^^^^ 
2. It is very evident also that the removable hardness in the 
former class (over 450 feet deep), far exceeds that in the lat- 
ter class. That is to say, the element of sulphuric acid is re- 
markably greater in the deepest wells, in one well the amount 
being 137.2 grains per gallon, and the average for eleven such 
wells being 23.5 grains. But the highest in the shallow wells, 
i. e., less than 450 feet, is 69.3 grains per gallon ; the average of 
eight wells being 12.6 grains per gallon, or about one-half that 
in the deeper wells. The amount of permanent hardness in the 
Glenwood-Inglewood water is 18. grains per gallon. 
3. It is reasonable also to infer that the stronger mineraliza- 
tion of the deep waters, as apparent both to the taste and to the 
sense of smell, is attributable to the presence of this high per- 
centage of sulphuric acid. When fresh, these deep waters often 
give also a distinct odor of sulphuretted hydrogen. These 
qualities, however, serve to purify the lake waters of the St. 
Paul system. 
It is for these reasons that the discussion which is presented 
in this paper discards for city uses these deeper wells, and ap- 
proves those waters coming from the shallower basins. 
What Has Been Shown. 
If a short resume be made of what has now been shown it 
comes to about the following : 
1st, There are several water basins below the city of Minne- 
apolis, extending widely into the country, of which but two 
need to be taken ito account, namely, one getting water at about 
400 feet, another at about 200 feet. 
2nd, The waters afiforded by these two basins are not strik- 
ingly different in hardness from the water of the Mississippi 
river, but the water from the shallower reservoir is sometimes 
softer than the water of the Mississippi river. 
3rd, The quantity of the supply is inexhaustible and more 
reliable than the supply from the Mississippi river itself. 
4th, The cost of sinking the necessary number of wells to 
supply 30,000,000 gallons per day from the 400-foot series need 
not exceed $100,000.00 at the outside. 
Thanks. I need not say that it affords me very great pleas- 
ure to have the opportunity of presenting this important ques- 
tion before a committee of the civic societies of the city under 
the auspices of the Real Estate Board. I have taken considera- 
