works with great uniformity.

Every grain of deposit contains at least 7-10 its weight of gold,
easily discoverable by the blowpipe. Such gilding is continually
deteriorating, which with good chloride and distilled water may be
prevented. Distilled water should also be used for the hyposulphite.
and for cleaning plates. Any good, clear water may be afterwards used
for washing off, with equally good results. I am very rarely troubled
with specs, and deem this as the main reason.

With a portable still attached to a cooking stove, I obtain half a
gallon of water per hour, and with very little trouble. A small tin
retort or still connected with a Leibig's condenser, would not add much
to the "traps" of the travelling operator, and save him many a
disreputable specimen.--T. J. BAILEY.--Humphrey's Journal.

PRACTICAL HINTS ON THE DAGUERREOTYPE.

The following is from Humphrey's Journal, vol. 5, and from the pen of
Dr. WM. HARRINGTON, one of the most able writers upon the subject of
the Daguerreotype in this country:

THE CAUSE OF THE DIFFICULTY THAT SOMETIMES OCCURS TO PREVENT THE
PRODUCTION OF A CLEAR IMPRESSION UPON A DAGUERREOTYPE PLATE.

Beyond all doubt this is traceable to dampness. Truly this is not a
new thought; but where does this dampness come from? How does it
originate, and where is it located? Generally it has been referred to
a point entirely remote from its real location.

This dampness exists particularly upon the surface of the plate; is
obviously derived immediately from the atmosphere; and is owing to a
certain relative temperature of the plate with the hygrometric
condition of the atmosphere.

Whenever this relation exists between the plate and atmosphere, a
precipitation of moisture takes place upon the surface of the plate,
which render all efforts at polishing impracticable. This interference
is not confined to the buffing operation alone, but sometimes is
discoverable even in the ordinary process of scouring. Every one at
all experienced in this art will remember that it is not always an easy
matter for him, by scouring, to bring his plate to the desired lustre.
All his efforts become unavailing; the more he rubs, the duller the
surface of his plate appears; and although he renews his cotton
repeatedly, still he is obliged to content himself with an
unsatisfactory finish.

This relative condition is not confined to any particular season of the
year, nor to any certain thermom