curate exhibition of the veins which
extend in every direction through it, more correctly than the finest
drawing. And this process is so simple, and the materials so easily
obtained, that any person, with a little practice to enable him to
apply the right quantity of smoke to the oil-paper, and give the leaf
a proper pressure, can prepare beautiful leaf impressions, such as a
naturalist would be proud to possess.

2336. Dry Botanical Specimens for Preservation.

The plants to be preserved should be gathered when the weather is dry.
Place the ends in water, and let them remain in a cool place till the
next day. When about to be submitted to the process of drying, place
each plant between several sheets of blotting paper, and iron it with
a large smooth heater, pretty strongly warmed, till all the moisture
is dissipated. Colours may thus be fixed, which otherwise become pale,
or nearly white. Some plants require more moderate heat than others,
and herein consists the nicety of the experiment; but it is generally
found that if the iron be not too hot, and is passed rapidly yet
carefully over the surface of the blotting paper, it answers the
purpose equally well with plants of almost every variety of hue and
thickness.

In compound flowers, with those also of a stubborn and solid form, as
the Centaurea, some little art is required in cutting away the under
part, by which means the profile and forms of the flowers will be more
distinctly exhibited. This is especially necessary when the flowers
are fixed down with gum upon the paper previous to ironing, by which
means they become almost incorporated with the surface. When this very
delicate process is attempted, blotting-paper should be laid under
every part excepting the blossoms, in order to prevent staining the
white paper. Great care must be taken to keep preserved specimens in a
dry place.

2337. Collecting and Laying out Sea-weeds.

"First wash the sea-weed in fresh water, then take a plate or dish
(the larger the better), cut your paper to the size required, place
it in the plate with fresh water, and spread out the plant with a
good-sized camel-hair pencil in a natural form (picking out with the
pin gives the sea-weed an unnatural appearance, and destroys the
characteristic fall of the branches, which should be carefully
avoided); then gently raise the paper with the specimen