The desiccative powers of lime are familiar to chemists, and, I believe, to
many practical men; but I do not know of lime having been used for the
above purpose.
A strong chest, in my possession, containing important papers (title-deeds,
marriage certificates, &c.), gradually became damp, and subjected its
contents to a slow process of decay. This arose, I found, from a defect in
its construction, wood having been improperly introduced into the latter,
and concealed; so that some singular chemical compounds would appear to
have been formed. The papers were gradually injured to an extent enforcing
attention; and the process continued in them after their removal into a
well-constructed chest, giving me the impression of a process resembling
the action of a ferment. Several attempts were made to dry them by fires,
the rays of the sun, &c.; but the damp was always renewed.
They were thoroughly dried in a very few days, and permanently kept dry, by
placing and keeping in the chest a box containing a little quicklime.
At a later period, a large closet, so damp as to render articles mouldy,
was thoroughly dried, and kept dry, by a box containing lime.
The chest was about 2 feet 6 inches, by 2 feet 1 inch, and 1 foot 8 inches;
and the box placed in it for several months was about 1 foot 2½ inches, by
8½ inches, and 3 inches. After about a year, although no very perceptible
damp was discovered, yet, in consequence of the value of the papers, and
the beauty of some of them as manuscripts, I introduced two such boxes.
These proportions were selected to enable the boxes to stand conveniently
on a shelf with account-books and packages of papers.
The closet is about 11 feet 4 inches, by 2, irregular dimensions, which I
estimate at about 6 feet, and 2 feet 4 inches. The box used in this case is
1 foot 4 inches, by 11 inches, and 7 inches.
The lime should be in pieces of a suitable size. For the chest, I prefer
pieces about the size of a large English walnut; for the closet, of an
orange.
It is necessary either that the box should be strongly made, or be formed
of tin, or other metal, on account of the lateral expansive force of the
lime. Room for expansion upwards is not sufficient protection. The same
expansion renders it necessary that the box should not be more than
two-fifths filled with fresh lime.
I leave the tops open. If covered, they must be so disposed that the air
within the boxes shall freely communicate with that of the chest or closet.
I have used these boxes several years, and only changed the lime once a
year.