132 THE WEGETABLE KINGDOM. 
should be examined every day or two, to see that they are 
lying properly, and to prevent them from sticking to the paper. 
In most climates, artificial heat becomes necessary to facilitate 
their drying, so that mouldiness may not ensue. For this pur 
pose, each plant is placed between two or three sheets of paper, 
and after placing several layers of these above each other, 
they are put into an oven which is half cooled. There is no 
danger of the colours giving way, as might be supposed, from 
this rapid drying ; when this operation is completed the plauts 
are put in clean paper, each species being in a separate leaf. 
Bulbous plants are very difficult to dry from the quantity of 
moisture contained in them, and, indeed, often vegetate after 
they are in an herbarium; to prevent which, they ought to be 
plunged in boiling water for about a minute, and then placed 
between two leaves of brown paper, when they will dry rapidly, 
as the boiling water will have destroyed the vegetative func- 
tions. We must, however, avoid immersing the blossoms. 
The same notes must be put with each plant, as recommended 
at page 128; besides these, the height of the plant, the co- 
lours of its flowers, and its odour, should be attended to. 
When the herbal of a country is formed, it ought to be pack- 
_ ed in a large box and a little cotton with oil of petroleum 
| placed beside it, or a little oil of turpentine; the box should 
be covered with pitch, as before directed. 
The genus and species of many of the different kinds of 
wood used in commerce, are still unknown to Botanists; it is 
| therefore desirable that specimens of these should be sent 
home of ten inches or a foot long, and the whole breadth of 
the tree if possible, as also transverse sections ; these ought to 
be accompanied with a branch of the tree containing the 
leaves, and of flowers and fruit besides. 
It is not enough to bring home a single specimen of objects | 
of natural history, but as many as can conveniently be stowed | 
by the traveller; these will be found very useful to other na- 
turalists, and by exchanging them for other duplicates, will 
add greatly to the value of a collection; and, besides, our 
specimens are liable to accidents and decay, so that, in many 
points of view, duplicates will be found very useful. 
