be brought home adhering to their natural situations ; and un- 
less the species of the tree on which they grow is known to 
the traveller, a specimen branch should be imported at same 
time. 
It is of consequence also, to observe which way climbing and 
parasitical plants bind round the stems to which they adhere, 
that is, to ascertain whether they are dextral or sinistral plants. 
The naturalist must suppose himself in the place of the stem, 
placing himself with his face turned towards the south pole, 
and then mark whether they ascend to the right or left. Those 
whose head twists in the same direction which the sun appears 
to move in, are dextral plants. 
GEOLOGY AND MINERALOGY. 
Every mineral from the most common clay or sand, to the 
gem, ought to be collected. 
Specimens of rocks, such as granite, porphyry, limestone, 
slate, &c., should, if possible, be broken from fixed rocks, 
and not from loose masses, which are generally decayed. In 
selecting the specimens, one set ought to represent the differ- 
ent varieties of appearance presented by the rock in the fresh | 
state ; another the rock in its different states of decomposition. 
It is not sufficient for the geologist to content himself with 
_ possessing a simple specimen of any mountain rock. For he 
will find that they present considerable variety of structure in 
different districts, and these are very interesting to be brought 
together for comparison. By an accumulation of these, we 
may be assisted in coming to certain conclusions concerning 
their primary formation, and other geological facts. 
When the specimens of simple minerals or rocks contain 
crystals, they ought to be wrapped in fine paper, and then in 
cotton, and afterwards in several folds of strong wrapping- | 
paper. 
The specimens of rocks ought, if possible, never to be less 
GEOLOGY AND MINERALOGY. 135 | . 
than four inches square, and one inch in thickness, and of a | 
square form. As soon as they have been prepared, they should | 
be labelled, and put in several folds of strong wrapping-paper | 
to prevent friction. When paper cannot be procured, moss, or | 
other soft vegetable substances, may be substituted for it. 
