130 
EIGHTH REPORT. 
and that there “should not be more than one grain of organic matter to 
the gallon.” The.consensus of opinion arrived at during the discus¬ 
sions referred to, was that calcium carbonate in excess of 170 parts 
per million, is detrimental to health. A standard of purity based on 
the average chemical composition of the rivers and lakes of this coun¬ 
try, would no doubt demand a greater degree of purity than lias been 
decided as sufficient to insure health in Europe, but until such a stan¬ 
dard is framed by American experts in hygiene, municipalities will be 
constrained to assume that water which is good enough for the people 
of Europe, will suffice for the people of America. It seems but rea¬ 
sonable to assert, however, that water which makes a near approach to 
the danger line stated above, should be regarded with suspicion, and not 
used for drinking unless no better supply can be obtained. 
Not only is the standard of chemical purity just indicated, desirable 
in reference to the health of communities, but it has an important 
bearing on the commercial uses of water. The more nearly chemically 
pure a water is, the less the expense incident to the formation of 
“scale” in steam boilers, and the less the cost of soap used in connection 
with it. The maximum limit of mineral matter in solution, adopted 
by the United States Geological Survey, in reference to its use for 
generation of steam, is 140 parts per million. Each of the items just 
mentioned as well as several others in reference to the chemistry of 
water, becomes of great importance when the water supply of a city is. 
considered. 
There is an inferior as well as a superior limit, however, to the 
proportion of mineral matter which water should contain in solution 
in order to be wholesome, and certain water as that supplied directly 
by rain for example, may contain too small a percentage of mineral 
substances to be thoroughly desirable. The lower limit adopted at the 
Brussels Congress and subsequently confirmed at later conferences of 
a similar nature, is 130 parts per million for total mineral matter, and 
for calcium carbonate, sixteen parts per million. The most desirable 
proportions among the several mineral substances usually occuring in 
solution, has also been at least approximately determined, but will not 
be considered at this time. 
In reference to the “one grain of organic matter to a gallon,” stated 
by the Brussels Congress to be permissible in wholesome water, it is 
evident that uncertainties might arise as to the true meaning intended. 
Disease producing germs are evidently not to be included within this, 
limit. A clearer and as is evident a moi*e reasonable conclusion in 
this connection, has been placed on record in an essay on the sanitary 
chemistry of waters, by Professor C. F. Chandler, for a term of year's 
President of the Board of Health of New York, which reads as foliows: 
“Organic matter of a purely vegetable origin, such as occurs to the ex¬ 
tent of one, two, or three grains per gallon, in country springs and 
wells, or in ponds and rivers, even when it contributes a tint of yellow 
to the water, is entirely harmless and unobjectionable. The nitrates, 
nitrites and ammonia salts found in wells in densely peopled towns are 
themselves harmless, but their presence proves the contamination of 
the water with the products of decomposition of animal refuse, and 
should always be viewed in the light of a warning of the presence of im- 
