PRESERVATION OF VALUABLE PAPERS FROM DAMP; DRYING CLOSETS.
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.