148 
IOWA ACADEMY OF SCIENCES. 
wagons. But a change in the location of the pumping 
station from about two miles southwest of the city to six 
miles north is for the present out of the question. Even 
using as much as possible of the material now owned the 
cost of the change would be about thirty thousand dollars. 
At the present location of the pumping station, south- 
west of the city, there is an abundance of water from a 
drainage area of 281 square miles. The entire flat near 
and above the plant is underlain by sand containing water 
charged with an abundance of iron bicarbonate, but it is 
not yet known whether this condition of the water 
actually persists in the bottom land down the river. It has 
already been found that the water, though wholesome and 
perhaps endurable so far as taste is concerned, is wholly 
unacceptable for cooking and for bathing. The iron can 
be precipitated by lye or by ammonia and the water 
strained, or it can be quite fully removed by allowing it to 
stand exposed to the air and then Altering it; but such 
processes are too troublesome to be acceptable. I have not 
been able to ascertain, either from published data or from 
experiment, whether iron bicarbonate in solution under 
pressure can be precipitated either by alum or ammonia 
and can be immediately Altered out under pressure as a 
fine sediment can be treated. This may be possible, for 
iron bicarbonate is very unstable, but as pressure is so 
effective in maintaining the bicarbonate of iron it must be 
proven that the bicarbonate can be so removed before it 
would be advisable to install a pressure filter. Without 
this evidence water that is free from iron must be obtained 
from some other local source. 
There is on the opposite side of the river from the pump- 
ing station a point of land in a large bend of the stream. 
The sand in the distant part of this bend and nearest the 
upland is charged with iron, but it is not known whether 
the sand which lies where the circulation of the ground 
water from the upper limb of the bend to the lower limb 
may not be washed free from iron, for the stream itself, of 
course, has no iron in solution. While it is possible that 
