_Hockin's Short Sketch._--Mr. Hockin is so well known as a thoroughly
practical chemist, that it may suffice to call attention to the fact of his
having published a little brochure entitled _How to obtain Positive and
Negative Pictures on Collodionized Glass, and copy the latter upon Paper. A
Short Sketch adapted for the Tyro in Photography._ As the question of the
_alkalinity_ of the nitrate bath is one which has lately been discussed, we
will give, as a specimen of Mr. Hockin's book, a quotation, showing his
opinion upon that question:
"_The sensitizing agent_, nitrate of silver in crystals, not the
ordinary fused in sticks, is nearly always confessedly adulterated; it
is thus employed:
"_The silver or nitrate bath._--Nitrate of silver five drachms,
distilled water ten ounces; dissolve and add iodized collodion two
drachms.
"Shake these well together, allow them to macerate twelve hours, and
filter through paper. Before adding the nitric acid, test the liquid
with a piece of blue litmus paper; if it remain blue after being
immersed one minute, add one drop of dilute nitric acid[3], and test
again for a minute; and so on, until a claret red is indicated on the
paper. It is necessary to test the bath in a similar manner, frequently
adding half a drop to a drop of dilute acid when required. This
precaution will prevent the fogging due to alkalinity of the bath, so
formidable an obstacle to young hands."
[Footnote 3: "Dilute nitric acid.--Water fifty parts, nitric acid one
part."]
_Photographic Society's Exhibition._--The Photographic Society opened their
first Exhibition of {17} Photographs and Daguerreotypes at the Gallery of
the Society of British Artists, in Suffolk Street, with a _soirée_ on
Tuesday evening last. Notwithstanding the inclemency of the weather, the
rooms were crowded not only by members of the Society, but by many of the
most distinguished literary and scientific men of the metropolis. The Queen
and Prince Albert had, in the course of the morning, spent three hours in
an examination of the collection; and the opinion they expressed, that the
exhibition was one of great interest and promise, from the evidence it
afforded of the extraordinary advance made by the art during the past year,
and the encouragement it held out to the belief that far greater excellence
might therefore still be looked for in it, was a very just one, and
embodied that given afterwards by the most competent authorities. We have
not room this week to enter into any details, but can confidently recommend
our readers to pay an early visit to Suffolk Street.
* * * * *
Replies to Minor Queries.
_"Firm was their faith," &c._ (Vol. viii., p. 564.).--These lines are to be
found in a poem called "Morwennæ Statio, hodie Morwenstow," published by
Masters in 1846, with the title of _Echoes from Old Cornwall_, and written
by the Vicar of Morwenstow. I agree with D. M. in the judgment he has
announced as to their merits; but hitherto they have been but little
appreciated by the public. A time will come however, when these and other
compositions of the author will be better known and more duly valued by the
English mind.