WATERS. 
a pneumatic apparatus. The method of se- 
parating and examining these different bodies 
shall be described hereafter. 
II. The presence of carbonic acid, not 
combined with a base, or combined in excess, 
may be detected by the following tests : 1. 
Lime-water occasions a precipitate soluble 
with effervescence in muriatic acid. 2. I he 
infusion of litmus is reddened ; but the red 
colour gradually disappears, and may be 
again restored by the addition ot more of the 
mineral water. 3. When boiled it loses the 
property of reddening the infusion ot litmus. 
III. The mineral acids when present, un- 
combined in water, give, the infusion of lit- 
mus a permanent red, even though the water 
has been boiled. £ergman has shewn that 
paper, stained with litmus, is reddened when 
dipt into water containing l -352 1 of sulphuric 
*cid. 
IV. Water containing sulphureted hydro- 
gen gas is distinguished by the following pro- 
perties : 1 . It exhales the peculiar odour of 
sulphureted hydrogen gas. 2. It reddens the 
infusion of litmus fugaciously. 3. It blackens 
paper dipt into a solution of lead, and preci- 
pitates the nitrat of silver black or brown. 
V. Alkalies, and alkaline and earthy car- 
bonats, are distinguished by the following 
tests: 1. The infusion of turmeric, or paper 
stained with turmeric, is rendered brown by 
alkalies, or reddish-brown it the quantity is 
minute. This change is produced when the 
soda in water amounts only to 1-22 17th part. 
2. Paper stained with Brazil wood, or the in- 
fusion of Brazil wood, is rendered blue ; but 
this change is produced also by the alkaline 
and earthy carbonats. Bergman ascertained 
that water containing 1 -9943th part of car- 
bonat of soda renders paper stained with 
Brazil wood blue. 3. Litmus paper redden- 
ed by vinegar is restored to its original blue 
colour. This change is produced by the al- 
kaline and earthy carbonats also. 4. When 
these changes are fugacious, we may con- 
clude that the alkali is ammonia. 
VI. Fixed alkalies exist in water which oc- 
casions a precipitate with muriat -of magnesia 
-after being boiled. Volatile alkali may be 
distinguished by the smell, or it may be ob- 
tained in the receiver by distilling a portion 
of the water gently, and then it may be dis- 
tinguished by the above tests. 
VII. Earthy and metallic carbonats are 
precipitated by boiling the water containing 
them ; except carbonat of magnesia, which 
is only precipitated imperfectly- 
VIII. Iron is discovered by the following 
tests 1. The addition of tincture of nut galls 
gives water containing iron a purple or black 
colour. This test indicates the presence of 
a very minute portion of iron, if the tinc- 
ture has no effect upon the water after boiling, 
though it colours it before, the iron is in the 
state of a carbonat. The following observa- 
tions of Westrum on the colours which iron 
gives to nutgalls, as modified by other bodies, 
deserve attention : 
A violet indicates an alkaline carbonat or 
earthy salt. 
Dark purple indicates other alkaline salts. 
Purplish red indicates sulphureted hydro- 
gen gas. 
Whitish and then black indicates sulphat of 
lime. 
2. The prussian alkali occasions a blue 
precipitate in water containing iron. If an 
Vo x. II. 
alkali is present, the blue precipitate does 
not appear unless the alkali is saturated with 
an acid. 
IX. Sulphuric acid exists in waters which 
form a precipitate with the following saline 
solutions : 
1. Muriat, nitrat, or acetat of barytes 
2. . - - strontian 
3_ lime 
4. Nitrat or acetat of lead. 
Of these the most powerful by far is muriat 
of barytes, which is capable of detecting the 
presence of sulphuric acid uncotnbined, when 
it does not exceed the millionth part ot the 
water. Acetat of lead is next in point of 
power. The muriats are more powerful than 
the nitrats. The calcareous salts are least 
powerful. All these tests are capable ot in- 
dicating a much smaller proportion of un- 
combined sulphuric acid than when it is com- 
bined with a base. To render muriat of 
barytes a certain test of sulphuric acid, the 
following precautions must be observed: I. 
The muriat must be diluted. 2. r I he alkalies, 
or alkaline carbonats, if the water contains 
any, must be previously saturated with mu- 
riatic acid. 3. The precipitate must be in- 
soluble in muriatic acid. 4. If boracic acid 
is suspected, muriat ot strontian must be tried, 
which is not precipitated by boracic acid. 5. 
The hydrosulphurets precipitate barytic so- 
lutions, but their presence is easily discover- 
ed by the smell. 
X. Muriatic acid is detected by nitrat of 
silver, which occasions a white precipitate, or 
a cloud in water containing an exceedingly 
minute portion of this acid. To render this 
test certain, the following precautions are ne- 
cessary : 1. The alkalies or carbonats must 
be previously saturated with nitric acid. 2. 
Sulphuric acid, if any should be present, must 
be previously removed by means ot nitrat of 
barytes. 3. “The precipitate must be inso- 
luble in nitric acid. 
• XI. Boracic acid is detected by means of 
acetat of lead, with which it forms a precipi- 
tate insoluble in acetic acid. But to render 
this test certain, the alkalies and earths must 
be previously saturated with acetic acid, and 
the sulphuric and muriatic acids removed by 
means of acetat of 'strontian and acetat of 
silver. 
XU. Barytes is detected by the insoluble 
white precipitate which it forms with diluted 
sulphuric acid. v 
XIII. Lime is detected by means of oxahc 
acid, which occasions a white precipitate in 
water containing a very minute proportion 
of this earth. To render this test decisive, 
the following precautions are necessary: 1. 
The mineral acids, if any should be present, 
must be previously saturated with an alkali. 
2. Barytes, if any is present, must be previ- 
ously removed by means of sulphuric acid. 
3. Oxalic acid precipitates magnesia but very 
slowly, whereas it precipitates lime in- 
stantly. 
XIV. Magnesia and alumina, d he pre- 
sence of these earths is ascertained by the 
following tests : 1. Pure ammonia precipitates 
them both, and no other earth, provided the 
carbonic acid has been previously separated 
by a mineral alkali and boiling. 2. Lime- 
water precipitates only these two earths, pro- 
vided the carbonic acid is previously remov- 
ed, and the sulphuric acid also, by means of 
nitrat of barytes. 
.88(y 
The a'umina may- be separated from the 
magnesia after both have been precipitated 
together, either by boiling the precipitate in 
pure potass, which dissolves the alumina and 
leaves the magnesia ; or the precipitate may 
be dissolved in muriatic acid precipitated by 
an alkaline carbonat, dried in tne temperature 
of one hundred degrees, and then exposed to 
t he action of diluted muriatic acid, which 
dissolves the magnesia without touching the 
alumina. 
XV. Silica may be ascertained by evapor- 
ating a portion of the water to dryness, and 
redissolving the precipitate in muriatic acid. 
The silica remains behind undissolved. 
Such is the method of detecting the differ- 
ent substances commonly found in waters. 
But as these different substances are almost 
always combined together, so as to constitute 
particular salts, it is not sufficient to know 
in general what the substances are which are 
found in the water we are examining ; we 
must know also in what manner they are 
combined. Thus it is not sufficient to know 
that lime forms an ingredient in a particular 
water, we must know also the acid with which 
it is united. Mr. Kirwan first pointed out 
how to accomplish this difficult task by 
means of tests. Let us take a short view of 
his method. 
I. To ascertain the presence of the differ- 
ent sulpbats. 
The sulpbats which occur in water are 
seven ; but one of these, namely, sulphat ot 
copper, is so uncommon, that it may be ex- 
cluded altogether. The same remark applies 
to sulphat of ammonia. It is almost unne- 
cessary to observe, that no sulphat need be 
looked for unless both its acid and base have 
been previously detected in the water. 
1. Sulphat of soda may be detected by the 
following method : I ree the w'ater to be ex- 
amined of all earthy sulphats by evaporating 
it to one-half, and adding lime-water as long 
as any precipitate appears. By this means 
the earths will be all precipitated except lime, 
aud the only remaining earthy sulphat will 
be sulphat of lime, which will be separated 
by evaporating the liquid till it becomes con- 
centrated, and then dropping into it a little 
alcohol, and ''after filtration adding a little 
oxalic acid. 
With the water thus purified, mix solution 
of lime. If a precipitate appears either im- 
mediately or on the addition of a little alco- 
hol, it is a proof that sulphat of potass or ot 
soda is present; which of the two, may be 
determined by mixing some ot the purified 
water with acetat of barytes. Sulphat of 
barytes precipitates. Fibre and evaporate 
to dryness. Digest the residuum in alcohol. 
It will dissolve the alkaline acetat. Evapor- 
rate to dryness, and the dry salt will deli- 
quesce] if it is acetat of potass, but effloresce 
if it is acetat of soda. 
2. Sulphat of lime may be detected by eva- 
porating the water suspected to contain it to 
a few ounces. A precipitate appears, which, 
if it is sulphat of liaie, is soluble in 500 pails 
of water ; and the solution affords a preci- 
pitate with the muriat of barytes, oxalic acid, 
carbonat of magnesia, and with alcohol. 
3. Alum may be detected by mixing car- 
bonat of lime with the water suspected to 
contain it. If a precipitate appears it indi- 
cates the presence of alum, or at least of su l 
