537 
liable to pollution by having steps leading down to the water’s edge. 
Under such conditions the danger of introducing impurities from the 
soles of dirty shoes is of course apparent. 
Unless a spring has a tight coping on all sides and is provided 
with a tight cover and spout, so that the water does not have to be 
dipped up, it falls short of the requirements of a sanitary supply. 
For convenience the water from the spring should be conducted by 
pipe to the house, dairy, and barn. 
In the recent investigation but few springs were found which were 
properly protected. Some of them had cement or tight stone coping 
on three sides with steps leading down on the fourth side. Some 
had a tight coping on all sides, but the coping was level with the ground 
and the water thus exposed to pollution. But in many cases the 
water ran out of fissures in the rock into a natural or artificial basin, 
or bubbled up from the bottom of such a basin. In these springs 
no special care was exercised to guard against pollution. 
The two photographs, numbers 44 and 45, given here show 
springs surrounded on three sides and over the top by natural rock 
but unprotected on the lower side in each case, and spring No. 44 is 
remote from sources of domestic contamination though it is in a 
pasture lot and is not fenced in. The dwelling is situated above 
and several hundred feet away up the hill shown to the right of 
the picture. The barn is still farther away in the same direc- 
tion. The ground intervening between the house and the spring is in 
sod. The water is pumped up by a windmill to a tank near the 
house. The spring could be perfectly protected with little difficulty. 
Spring No. 45 lies at the foot of the barnyard hill and is shown 
in the picture to the left of the dairy house. Some protection from 
wandering stock is afforded by the railing seen in the photograph. All 
the surroundings were untidy. There was filth up at the very edge 
of the spring. The fence seen to the left in the photograph incloses 
the hogpen, and above to the left is the barnyard, though it is true 
the slope does not incline directly from the barnyard to the spring. 
This is naturally an excellent supply and could be made to fulfill all 
sanitary requirements. 
CISTERNS. 
Where there is no spring and where it is not feasible for any reason 
to sink a well it becomes necessary to resort to cisterns, and if these 
are properly constructed and operated they may be made to fulfill all 
sanitary requirements. The walls should be water-tight, of course, 
both to prevent water from leaking out as well as to guard against 
pollution from without. The best cisterns are those constructed with 
two chambers divided by a porous brick partition through wdiich the 
water is filtered. The water from the roof is made to run into one 
