[However much we may agree in the views expressed in the latter part of
AN AMATEUR'S letter, we have been obliged to omit it, as it violates our
rule of not opening the columns of "N. & Q." to the recommendation of any
particular manufacturer.]
_Is it dangerous to use the Ammonio-Nitrate of Silver?_ (Vol. viii.,
p. 134.).--No: it is now generally used as the best of _marking inks,
without preparation_; and we have never yet heard of an explosion from
its use. Mr. Delamotte has evidently confounded this preparation with
the chloride of silver precipitated with _strong ammonia_, which, when
dried, forms the article known as _fulminating silver_; or by adding
to the oxide of silver lime-water, and afterwards a strong solution of
ammonia, a black powder is thrown down, which, when dried, is known as
_Berthollet's fulminating silver_. There is also one other, formed by
adding chloric acid to oxide of silver; after drying this, and then
adding potassa to a solution of it, the precipitate, by again being
dried, becomes an explosive compound.
The photographer forms a weak solution for his purpose with one of the
least soluble and _weakest_ of the ammoniacal preparations, and which,
by drying _around the stopper of the bottle_, is very unlikely to become
explosive, from its wanting the addition of another element as necessary
to the formation of an explosive compound. For my own part, I must say,
that I have found, from experience, all the compound solutions of silver
keep much better, and the photogenic effect more satisfactory, by mixing
only so much as I may require for immediate use, at this time of the year
especially.