e picture may be fixed by the
hyposulphite of soda, which alone, I believe, can be fully depended on for
fixing argentic photographs."

"The best process for fixing the photographs prepared with gold is as
follows: As soon as the picture is satisfactorily brought out by the
auriferous liquid, it is to be rinsed in spring water, which must be three
times renewed, letting it remain in the third water five or ten minutes.
It is then to be blotted off and dried, after which it is to be washed on
both sides with a somewhat weak solution of hydriodate of potash. If
there be any free chloride of gold present in the pores of the paper it
will be discolored, the lights passing to a ruddy brown; but they speedily
whiten again spontaneously, or at all events on throwing it (after lying a
minute or two) into fresh water, in which, being again rinsed and dried,
it is now perfectly fixed."

As the chrysotype will be no more referred to, we shall state, first, that
the image can be developed with a plain solution of silver nitrate or one
acidified with citric or any other organic acid, which generally gives a
brown impression that can be toned with an acid or alkaline gold bath, the
color varying with the solution employed; and secondly, that the process
may be employed to obtain outlines of any picture on paper or canvas to be
colored in oil-paints. The impression developed with gold terchloride is
pale blue, _quite permanent_, and does not at all interfere with the work
of the artist. The canvas should first be washed with a mixture of
alcohol and aqueous ammonia, then dried and rubbed with pumice stone
powder to give a _tooth_. The modus operandi suggests itself.

The researches of Mr. C. J. Burnett on the application of uranium salts
and other compounds to photography are recorded in the _Photographic
Notes_ of Ths. Sutton for 1857. We give in the following lines the most
interesting parts of the two papers of Mr. Burnett:

* * * "The next class of processes are dependent on the sensitiveness to
light of the salts of uranic oxide or sesquioxide of uranium, U2O3."

"In the first process, the paper being charged with the uranic salt and
exposed to the solar influence under the negative to be copied, is washed
with a solution of the ferridcyanide or red prussiate of potash. The
'Harvest Scene' in the exhibition, being from an albumen negative lent me
by Mr. Ross, the well-known Edinburgh photographer, is an example, the
sal