use of distilled water as preferable.

Cleaning Mercury.--Make a small bag of chamois skin, pour in the
mercury, and squeeze it through the leather. Repeat this several
times, and filter by means of a funnel made of paper, with a very small
aperture, through which it will escape and leave the particles of dust,
or other substances, in the paper. A paper with a pinhole through it
will answer as well, and it is less difficult to make.

Adhesive Paper.--Take gum arabic, four ounces, put it in a wide-mouthed
bottle and pour on water about one-third above the gum. Add half ounce
of isinglass, or fish glue, and a small piece of loaf sugar. Let all
dissolve, and spread over French letter paper, with a brush or piece of
sponge. If once spreading is not enough, perform the same operation a
second time.

Black Stain for Apparatus.--Dissolve gum shellac in alcohol, or procure
shellac varnish at the druggists', stir in lampblack, and apply with a
sponge or bit of rag. This will adhere to metal, as well as wood, and
is used for the inside of camera, tubes, etc.

Sealing Wax for Bottles.--Melt together six parts rosin and one
beeswax, and add a small quantity of lampblack; or, if red is
preferable, add red lead. Common white wax is best, as most chemicals
act less upon it.

When bottles containing bromine are to be sealed, it is well to grease
the stopper. This, however, only when the bottle is in frequent use,
for if it were to be sent by any conveyance it would be likely to fly
out.

Rouge.--The method employed by Lord Ross is probably unsurpassed in the
production of rouge. He has given his process as follows:

"I prepare the peroxide of iron by precipitation with water of ammonia,
from a pure dilute solution of sulphate of iron; the precipitate is
washed, pressed in a screw press till nearly dry, and exposed to a heat
which in the dark appears a dull, low red. The only points of
importance are, that the sulphate of iron should be pure, that the
water of ammonia should be decidedly in excess, and that the heat
should not exceed that I have described. The color will be a bright
crimson inclining to yellow. I have tried both potash and soda, pure,
instead of water of ammonia, but after washing with some degree of
care, a trace of the alkali still remained, and the peroxide was of an
ochrey color, till overheated, and did not polish properly."

Care should be observed to apply rouge in a dry state to the surface