188 
Preparation of a Herbarium 
Plants are preserved by drying them slowly between 
the leaves of unsized porous paper, by the application 
of a hot smoothing iron, or in a box of sand. In the 
first case the plants being spread carefully between the 
leaves of the paper, and retaining as much as possible 
their natural appearance, they are subjected to pressure, 
which at first should be moderate and afterwards gra- 
dually increased as the plants diminish in bulk by the 
absorption of the moisture. The pressure is applied 
either by means of a press constructed for the purpose, 
of two strong boards, of sufficient length and breadth 
to cover a large sheet of paper, and furnished at the 
corners with screws, or what answers equally well, a 
folio book placed upon the paper on a flat board or 
table, and loaded with other books. In preserving plants 
in this manner, when much nicety is required, every pre- 
caution should be observed not to wound or injure any 
of their parts by which a copious flow of the juices is 
produced. If a large quantity of paper be employed, 
the plants often dry perfectly without being shifted, but 
when they are crowded together in the same paper it is 
necessary to change their place, and at the same time 
to dry the paper daily. 
The application of a hot smoothing iron answers, in 
some cases, sufficiently well, particularly for drying suc- 
culent or juicy plants ; but it ought to be applied slowly 
and cautiously, and with a considerable quantity of pa- 
per. 
The colour of some plants is retained in higher per- 
fection by drying them in- a box of sand. After the 
specimen has been pressed for ten or twelve hours ac- 
cording to the former method, it is placed within a sheet 
of blossom paper, and laid in the box on a layer, an inch 
