66 
ANALYSIS OF POTABLE WATERS. 
sulphates, as a small quantity of sulphate of lime may occasionally be deposited if the 
quantity of sulphates he considerable. 
It is easy to convert the report of the number of grains per gallon (70,000) into parts 
in 1,000,000 (or what amounts to the same thing, to milligrammes per litre), by dividing 
the result by 7, and multiplying by 100. If the quantities per litre have been obtained 
in milligrammes, the proportion in grains per gallon is given by the converse operation 
of dividing by 100 and multiplying by 7. 
It may for the present be expedient, in accordance with popular usage, to continue to 
report the contents of the water per gallon, but the decimal report should never be 
omitted, as at no distant period we must anticipate that our insular prejudices in favour 
of our inconvenient system of weights and measures, will disappear before the manifest 
advantages of the decimal notation and the metrical system ; and it certainly is to be 
expected from our men of science that by the adoption of the method in their reports 
to the public, they will facilitate and hasten its introduction. It is with the view of 
aiding in this respect that I have in this paper given the weights and measures on the 
English method, and also their equivalents on the metrical system,—perhaps, in some 
measure, at the expense of succinctness, though I hope not of perspicuity. 
In reporting a water, therefore, it might be convenient to sum up the results in some 
such form as the following:— 
Grains Parts per 
per gallon. 1,000,000. 
Appearance . . . 
Colour in two-foot tube 
Amount of sediment. 
Containing { ^“bmtible 
° l Inorganic residue . 
Taste at 86° (30° C.). 
Odour. 
Hardness on Clark’s scale.. 
Ho. after boiling one horn*.. 
Oxygen absorbed by organic matter from permanganate 
Total solid contents. 
Consisting of -f J olat j lc f nd combustible matter . . 
& f Fixed salts. 
Earthy carbonates 
The fixed salts 
containing . 
^Chlorine. 
Sulphuric acid (S 0 3 ). 
Nitric acid (N0 5 ). 
Soluble silica. 
Lime. 
; Magnesia. 
Oxides of iron and manganese, alu¬ 
mina, and phosphates . . . . j 
Potash (KO). j 
SodaNaO. 
'Ammonia 
Total gases dissolved ...... 
Carbonic acid (C 0 2 ) 
Oxygen . . . . 
Nitrogen .... 
Ratio of oxygen to nitrogen . . . 
Consisting of 
Cubic inches Yols. 
per gallon. in 1000. 
Journal of the Chemical Society, 
