1028. The greater part of plants dry with facility between the leaves of books or other printed paper, the smoother the better. If there be plenty of paper, they often dry best without shifting; but if the specimens are crowded, they must be taken out frequently, and the paper dried before they are replaced. The great point to be attended to is, that the process should meet with no check. Several vegetables are so tenacious of their vital principle, that they will grow between papers; the consequence of which is, a destruction of their proper habit and colours. It is necessary to destroy the life of such, either by immersion in boiling water, or by the application of a hot iron, such as is used for linen, after which they are easily dried. The practice of applying such an iron, as some persons do, with great labour and perseverance, till the plants are quite dry, and all their parts incorporated into a smooth flat mass is not approved of. This renders them unfit for subsequent examination, and destroys their natural habit, the most important thing to be preserved. Even in spreading plants between papers, we should refrain from that precise and artificial disposition of their branches, leaves, and other parts, which takes away from their natural aspect, except for the purpose of displaying the internal parts of some one or two of their flowers, for ready observation. In Comferï¾µ, Ericeï¾µ, and some other orders, the leaves are apt to fall off, after drying; but it is said that this may be prevented by plunging the specimen, when newly gathered, for a minute in boiling water, though this is not always efficacious. The most approved method of pressing is by a box or frame, with a bottom of cloth or leather, like a square sieve. In this, coarse sand or small shot may be placed, in any quantity. Very little pressing is required in drying specimens ; what is found necessary should be applied equally to every part of the bundle under the operation, and this can only be done by the use of an equalising press of granulated matter, of compressed air, or of a bag of water. Dr. Lindley suggests putting the specimens between cushions in a press resembling a napkin-press, and putting it in the sun, or before a hot fire; and plants have been occasionally dried by placing them between layers of cotton wool under a hearthrug before a fire-place. A gentleman in the neighbourhood of Birmingham has been very successful in drying flowers and preserving their colours, particularly the blue, which is very fugitive, by the following process: he bakes the London clay, and reduces it to fine powder; he then spreads some of the powder upon writing paper, and on this lays the flower, after which the flower is completely covered with more of the powder, lightly sprinkled over it, and the whole is put into the press. He observes, 'I think it stands to reason that the colour ought to be preserved by this course, for I believe it is the vegetable acid which exudes from the swollen part of the flower (viz. the ovary, &c.) that decomposes the colour. Now, though blotting paper will receive this acid in drying, it only aggravates the evil, because it cannot dispose of the acid, but merely spreads it over a larger surface. Hence, I find that thick paper dries flowers better than blotting paper. Thus a blue bell dried on the former retains a thin line of colour about the edges of the corolla; but in the latter, loses its colour entirely.' (C. M. I., August 28. 1848.)
