314 EXPERIMENT STATION RECORD. 



hardness ranges from 150 to 500 parts per million and seldom falls below 200 

 parts. " Considered as to bacteriological purity the well waters of north- 

 central Indiana are good." 



Underground waters for farm use, M. L. Fuller ( U. S. Geol. Survey, Water- 

 Supply Paper No. 255, pp. 58, 2)?s. 17, figs. 27). — This paper states that of the 

 needs of the farmers of the United States " few are greater than that of purer 

 water supplies. Farms, which are generally remote from towns, cities, or other 

 areas of congested population, seem to be almost ideally situated for obtaining 

 pure and wholesome water. In reality, however, polluted water is exceedingly 

 common on them and typhoid-fever rates are usually greater in country districts 

 than in cities. Typhoid fever is now almost universally believed to be transmit- 

 ted solely through dfuik or food taken into the stomach, and is especially liable 

 to be comniuiilcated by polluted waters obtained from shallow wells near spots 

 where the discharges of typhoid patients have been thrown upon the ground 

 and subsequently carried down through the soil and into the wells, and it is 

 doubtless principally this fact that makes the disease so common in farming 

 regions. 



" Many of the failures to protect adequately the water supplies used for drink- 

 ing arise from a lack of knowledge of the manner in which waters circulate 

 through the ground and of the ways in which they may become polluted. In- 

 formation on these subjects must needs be of value, and it is with the object of 

 supplying this information in so far as it may be possible to furnish it in a brief 

 paper, that the present report has been prepared." 



The paper discusses sources of water supply, underground waters (springs and 

 wells) and their protection, cisterns, and the combination of wells and cisterns. 

 Discussing the relative safety of water from different water-bearing materials 

 the author states that in general waters from sands and gravels if taken from a 

 considerable distance below the surface are safe to use. Waters from clay are 

 likely to be mineralized, but are as a rule free from contamination. Waters 

 from till, sandstone, conglomerate, quartzite, shale, and slate are generally free 

 from contamination. Waters from limestone, particularly in the vicinity of 

 buildings or settlements, are frequently contaminated and unfit for use. " This 

 is not because of the amount of lime dissolved, but because of the fact that the 

 water falling on the surface as rain often plunges directly through basins or 

 sinks into the underground channels instead of slowly filtering downward 

 through the soil and into the rock, as in most other materials. This water 

 carries with it the impurities washed or otherwise brought to the sink and 

 bears them along through underground passages to distant points." 



On account of the joints and fissures which occur in granite, gneiss, and 

 schist, waters from these rocks are frequently contaminated, particularly in 

 cities and other thickly populated regions. 



" Of the various sources of water supply the ground water is the most satis- 

 factory for farm use, because it is least liable to pollution, and streams and 

 ponds are the most unsatisfactory, because of the ease and frequency with 

 which they are contaminated. Fortunately, however, the latter are very seldom 

 used for drinking and domestic purposes, being utilized mainly for stock, on 

 which the effect of moderate pollution is not apparent. The underground sup- 

 plies, whether from wells or springs, although safe in many localities, are far 

 from being universally so, the safety depending mainly on their location and on 

 the nature of their protection." 



When carefully made, cisterns are generally safe to use, and cistern water 

 being very soft is highly prized for domestic purposes. 



Sterilization of large quantities of water by ultraviolet rays, Urbain, 

 C. SCAL, and A. Feige (Compt. Rend. Acad. Sci. [Paris}, 151 {1910), No. 18, 



