1822] 
lime, in five ounces of the water above 
mentioned, to consist of 
“oy 48 lime, ; 
.77 carb. acid, 
‘ 1.25 
being about one grain of salt in 2000 
of water. This kind of water is hard, 
and curdles soap; but it is much sof- 
tened by boiling, and deposits the in- 
crustation so often found in kettles, &e. 
If water contains sulphate of lime along 
with supercarbonate, the same treat- 
ment may still be adopted, as far as 
respects the supercarbonate. I have 
recently found, with some surprise, 
that the supercarbonate of lime, as I 
call it, existing in waters, or made 
artificially, is rather an alkaline than 
acid compound. 
3, Acetate and Nitrate of Lead Tests. 
—These salts are easily obtained in 
great purity, and are excellent tests 
for carbonic and sulphuric acid, which 
they precipitate immediately in combi- 
nation with the lead. If the precipi- 
tate be treated with nitric acid, the 
carbonate of lead is instantly dissolved, 
and the sulphate of lead (if present) 
remains undissolved, and may be col- 
lected and dried; from which the 
quantity of sulphuric acid may be de- 
termined. | 
4. Nitrate and Muriate of Barytes 
Tests —W hen the object is to ascertain 
the presence of sulphuric acid, either 
free or combined, these are the best 
tests. The sulphate of barytes is per- 
haps the most insoluble salt known. 
Even rain-water collected from slated 
houses, though softer than spring or 
river water, exhibits by these tests one 
grain of sulphuric acid in twenty or 
thirty grains. 
5. Oxalie Acid Test—When the 
object is to obtain the lime, either free 
or combined, in any water, this is the 
best test. It may be proper to adda 
little ammonia in some cases of com- 
bined lime. The oxalate of lime 
slowly precipitates in. the state of an 
insoluble salt. The quantity of lime 
may be ascertained, either by collect- 
ing the precipitate, or by carefully and 
gradually adding the due quantity of 
acid, and no more, when the strength 
of the acid has been previously ascer- 
tained. 
6. Nitrates of Silver and Mercury 
Tests.—These are tests of muriatic 
acid or of muriates; the muriates of 
silver and mercury are formed, both 
insoluble salts. It does not often hap- 
Monruty Mac. No. 368, 
Literary and Philosophical Society of Manchester. 
441 
pen that spring-waters contain notable 
proportions of the muriatic acid, either 
free or combined. 
7. Sulphuretted Hydrogen-water and 
Hydro-sulphuretsx—These are excel- 
lent tests for lead, mercury, and several 
metals, giving peculiar insoluble preci- 
pitates of the sulphurets of those me- 
tals. One grain of lead precipitated 
by sulphuretted hydrogen, would be 
sufficient to give a great many gallons 
of water a dark-brown tinge. When 
sulphuretted hydrogen is found in mi- 
neral waters, as those of Harrowgate, 
it may be known by the smell; but 
solutions of lead are much superior 
tests, giving a black or brown tinge to 
such waters immediately. 
8. Tincture of Galls and Prussiates 
of Potash and Lime Tests——These are 
proper for the detection of iron, the 
former giving a black precipitate, and 
the latter a blue one; but a portion of 
the solution of oxymuriate of lime re- 
quires to be added previously to the 
water, if it contains the green oxide of 
iron in solution, in order to convert it 
1o the red oxide. 
There are many other tests than 
those I have enumerated, but they are 
more!than can usually be wanted in 
the analysis of ordinary springs. My 
object.is not to give a catalogue of 
tests, but to show in what manner 
their application may be improved, 
and reduced to a system intelligible to 
moderate proficients. 
The improvements I would propose 
in the use of tests are, that the exact 
quantities of the ingredients in cach 
test should be previously ascertained 
and marked on the label of the bottle; 
this might easily be done in most of 
them in the present state of chemical 
science. We should then drop in 
certam known quantities of each from 
a dropping tube graduated into grains, 
till the required effect was produced ; 
then, from the quantity of the test re- 
quired, the quantity of saline matter 
in the water mizht be determined 
without the trouble of collecting the 
precipitate; or, if this was done, the 
one method would be a check upon 
the other. 
I shall now close this imperfect 
sketch by a few observations and ex- 
periments, which I have noticed in 
the course of the present weck, rela- 
tive to the subject before us. 
I assayed the water supplied by the 
Manchester water-works, and found 
it nearly as I expected; river-water 
« ra js 
