IOWA ACADEMY OF SCIENCE 
139 
parts. On Iowa standards a town witb. a supply of water containing 500 parts 
of solids per million may consider itself fortunate in this respect; 700 parts 
may he considered fair, and 1,000 parts or even more, tolerable. For boilers 
and most industrial purposes none of these could be considered very good. 
One railroad in the state has classified its waters according to standards as 
follows: less than 134 parts, of incrusting solids, very good; 200 parts, good; 
300 parts, fair; 450 parts, poor; 600 parts, had; over 700 parts, very had. 
According to this standard and its own analyses of waters along its lines no 
water can be considered very good; only- eight of its waters are good; thirty- 
seven are fair, and eighty-eight are poor to very bad. If the 123 waters of 
this road may be taken as representative and the standard quoted as valid, 
then about tw'O-thirds of the Iowa waters are poor to very bad for boiler use. 
The case is really worse. Railroads care little about the sanitary “condition 
of their boiler waters, and they take them from- rivers, ponds and slough wells 
by preference because they are softer than the waters from deeper wells such 
as supply cities. Of city supplies probably far more than two-thirds are really 
poor to very bad for boilers. 
That hard waters form boiler scale and are very likely to be corrosive are 
facts too well known by this body to require discussion; also, that scale de- 
creases the efficiency of the boiler, and corrosion means early and frequent 
repair and short life of the boiler. 
Many means have been devised with the object of avoiding these difficulties. 
From the standpoint of the chemist there is only one right way, if the water 
is to be used at all and is not bad beyond possibilities of treatment. Since this 
method has now been introduced on a very large scale in this state by one of 
the largest corporations and has proved very successful, at any rate a brief 
statement for record seems desirable. But first as to palliatives and quack 
remedies. 
If one wishes to avoid the difficulties attending the use of a hard water for 
boilers or other industrial purpose, the most obvious thing to do is to soften 
it, if this is practicable. There is nothing new in the idea of softening water; 
the chemistry of it has been known for a long time, but there are new develop- 
ments in methods and the scale on which it may be carried on, at any rate in 
this state, where on account of the hardness of the waters it should be a 
matter of very great industrial importance. In order to make more clear the 
scientific character and efficiency of the method I have mentioned it may be 
well to describe briefly two palliative methods as carried out on a small scale. 
One method is by use of the pre-heater, the source of heat being usually 
exhaust steam. It is a matter of economy to feed the boiler with heated water, 
and the heating causes the precipitation and settling out of a considerable 
portion of the calcium carbonate. Sometimes a boiler compound or an alkali 
is added to the heater, thus removing a portion of the permanent hardness. 
The method is good so far as it goes, but the apparatus is usually too small 
to allow proper settling, it is troublesome to manage and its efficiency is farther 
restricted by the want of knowledge and care of the individual engineer. 
Perhaps the most generally used and the worst method is that of using 
alkalies and so-called “boiler compounds” for the precipitation of the solid 
matter in the boiler. This makes the sludge where it will do the most harm. 
It may cause foaming, it necessitates frequent cleaning, it may settle in a com- 
pact mass when the boiler is out of use and cause overheating of the covered 
