142 DEATH OF HORSES AND COWS FROM DRINKING RAD WATER. 
portional to the quantity of the above-named compounds 
contained in it; and when we state that a water has such 
and such a degree of hardness/'’ we mean that the total 
amount of lime^ magnesia^ and other hardening salts 
existing in it, is chemically equivalent to so many grains of 
chalk in a gallon of the water. For example, a water of 10° 
of hardness is one containing an amount of lime and magnesia 
salts of different kinds equal in its power of decomposing and 
curdling soap to 10 grains of chalk in a gallon of water. This 
explanation is not rigidly correct, but is sufficiently accurate 
for most practical purposes. 
* If the reader will now refer to page 79, he will find it 
there stated that in the ^^dike water the total solids 
amounted to 12’6 grains per gallon, and that the total hard¬ 
ness was 30°. Certainly these statements are irreconcilable, 
for they mean, if they mean anything at all, that out of 12‘6 
grains of solid matter of every kind, there were 30 grains of 
chalk, or their chemical equivalent of earthly salts. It need 
scarcely he remarked that one of these results must have 
been impossible, and that if the estimation of the total solids 
was correct, that of the hardness must have been incorrect, 
and vice versa. 
Dr. Truman next refers to the general difference in 
condition of combination of the earthy salts by stating 
that the permanent hardness of the dike water was 30°, or 
the same as the total hardness; nevertheless, he informs 
us that after precipitation with lime the degree of hardness 
was 24°. This latter, assuming such results to have been 
actually obtained, I, and I believe all other chemists, would 
have called the degree of permanent hardness, i.e., that hard¬ 
ness which cannot be removed by lime or boiling, and which 
is due to the presence, not of the carbonates, but to the 
sulphates, nitrates, and other salts of lime and magnesia. 
The difficulty of interpreting this analysis is furthermore 
increased by another and unintelligible statement, to the effect 
that, after precipitation with lime and boiling, the degree of 
hardness was 22*5. 
We now come to the chlorine in the dike water, which, Dr. 
Truman reports, amounted to 1*367 grains per gallon. If this 
be so, how comes it, assuming, as the Doctor evidently does, 
that it existed entirely as chloride of sodium, that there were 
only 1*759 grains of this salt in a gallon of the water, instead 
of 2*25 grains, which is the quantity equivalent to 1*367 
grains of chlorine ? 
On looking over a detailed account of the constituents of 
the 12*5 of total solids (12*6 was the number first given), it 
