ee ae ee ee 
sisi 
Analysis of Sea Water. 17 
should ’still remain in it. The ether was directly introduced into 
a glass bottle, containing a solution of caustic potash fully suffi- 
cient to discolor the ether, when after evaporation and ignition it 
was dissolved in water, and carefully neutralized with hydro- 
chlorie acid. The concentrated solution was mixed with a few - 
drops of an ammoniacal solution of chloride of silver prepared 
thus: one part of a concentrated solution of chloride of silver in 
ammonia, mixed with one part of ammonia and one part of wa- 
ter. A few drops of this mixture produced no turbidness in a 
solution of chloride of sodium, but indicated a very minute quan- 
tity of bromine. When no further turbidness was produced by 
an additional drop of this ammoniacal solution of the chloride of 
silver, the fluid under treatment, which was kept in an open ves- 
sel, was heated in a sand-bath until the ammonia was almost 
~ evaporated. - A few drops of the test were again added, until it 
no longer produced turbidness, when the glass vessel was again 
placed in a sand-bath, until the fluid, after having been heated, 
gave no further indication of bromine; it was then tested again” 
with chlorine. When the proportion of the chlorides to the bro- 
mides is not too large, scarcely a faint yellowness will be produ- 
ced; if, however, it is, the bromine must again be separated by 
chlorine and ether, and the before-mentioned process repeated, 
when the last traces of bromine will be separated as bromide of 
silver, which is to be treated like the iodide of silver before it 
is weighed. In this manner I have been able to detect the 
smallest proportion of an iodide and bromide when accompanied 
by a great quantity of chlorides, and have also been enabled to 
separate them and to ascertain their respective quantities. Should 
the quantity of iodine be much larger than that of bromine, it 
would be requisite to evaporate a little of the ammonia; and al- 
though the addition of the ammoniacal solution of chloride of 
Silver, employed as a test for iodine, no longer produces turbid- 
ness, it is still necessary to add another drop of the precipitating 
fluid, in order to ensure the separation of every trace of iodine. 
This is the more important, as the iodide of silver is not entirely 
insoluble in ammonia ; and although the quantity dissolved might 
be exceedingly minute, still this repetition is necessary in an ac- 
curate analysis. ‘The same precaution must be observed in the 
- separation of bromine, as bromide of silver is to some extent 
a 
soluble in ammonia, for it is obvious, that by the addition of the © 
Vol. xxxvi1, No. 1.—Oct.—Dec. 1839. ~ 3 ee 
