pass. They will choose the largest, note their size, and break some of these fragments. They will also take some of the smallest, exemplifying the variety of aspect. The further these fragments are brought, the less they become.

Wherever a rock rises, either in the middle of a water or country, travellers must observe if this rock be all of the same substance, whether homogeneous or composite, or if it be formed of different layers. In the first case, they will detach a fragment. In the second, they will observe the relative position of the strata, their inclination and thickness; they will take a specimen of each, putting the same mark on all the specimens which come from the same mountain, and a particular number on each of them, to indicate the order of their superposition or their reciprocal situation. If the traveller who will collect these specimens, can join a sketch to the simple mention of these particulars, indicating the form of the mountain, and the thickness and inclination of these layers, he will perform an essential service. In case the rock be an isolated peak, it will be well to examine and draw two faces, to confirm the inclination of the strata.

It will be useful to collect the sand of rivers, especially those which carry metallic spangles with but the sand must be taken as far from the mouths as possible.

them ;

In some countries, isolated masses are found, to

which the people attribute a singular origin; the traveller will take fragments of them, some may be aerolites, others may have been transported by the revolutions of the globe.

In gathering the fragments of rocks, mines, volcanic productions, fossil organised bodies, the most essential thing is to notice their bearing, that is to say, the nature of the soil where they are found, and their position relative to the minerals which environ them.

The basaltic layers merit a particular attention, either in themselves, or with respect to the soils which support or which cover them: the traveller will remark if they are divided into irregular masses, in tables, prisms, and what is their disposition. He will observe if they contain the remains of organised bodies, and he will take care to collect specimens of the different states, as well as of the substances upon which the basalt reposes. He will particularly ascertain if there be any interposition of scorified matter, or of those beds of an earthy aspect, to which the Germans give the name of wakke, and which are not supposed to be volcanic.

The trap porphyries or trachytes, merit the same attention: they are particularly distinguished from primitive and transitive porphyries, by the absence of quartz and the presence of pyroxene.

pieces of a large size; specimens from two and a half to three inches, and about an inch and a half thick, are sufficient. He will only take large masses when they contain a fossil animal.

To pack the specimens, we first cover them with fine paper; above this paper we put that on which the note is written, then a second fine paper, which we cover with tow, and envelope the whole in brown paper. We then arrange all the specimens in a case, close upon one another, filling the interstices with cut paper or tow, so that the whole forms a mass, which nothing can disturb. The case should be covered with pitch, to defend it from air and damp.

We have a few words to add respecting the packing. When the cases are filled, closed, and covered with pitch, they should be enveloped in an oiled canvas, and placed in a part of the vessel where they may remain until their arrival; sheltered as much as possible from excessive heat, and out of the reach of rats. It is desirable that they should not be opened or unpacked at the quays, or custom-houses, or until they reach their destination, as there is always a risk of their being broken or injured.

*

* Having separated a specimen from the rock, its sides or edges should be broken or reproduced with the small hammer, (striking the specimen as it rests in the palm of your hand,) in

Few travellers will want a sufficient interest in Natural History, but many may not be able to spare the time to act up to all the particulars of our instructions. Even to these we shall be grateful, if they will send us skins of animals in cases covered with pitch; small animals, thrown pellmell into a barrel of spirituous liquor; seeds gathered at random; and minerals, with a note indicating the place where they were collected. We will only add, that the more attention they can afford to our instructions, the more they will realise our views for the benefit of science and our country. These instructions have not been compiled for those who make Natural History a secondary object, but for those who devote themselves to it from preference or opportunity; we must observe, that we will gratefully return such of our duplicates as they may desire, towards the completion of their own collection, in exchange for the objects they may transmit to us, by such European vessels as touch in their neighbourhood.

order that they may be perfectly fresh, the original surfaces being subject to alteration, from long exposure to the atmosphere.

162

BOTANY.

GENERAL OBSERVATIONS.

THE nearer we advance to the equator, the larger we find the plants. The most commodious size for the paper of the herbarium is from fifteen to eighteen inches long, and eight to ten wide. We should be provided with several planks of the same size as our paper; these planks should be formed of two thinner ones, their surfaces being glued together; so that the grain of the wood of one may go length-ways, and the grain of the other breadthways; without this precaution they are apt to break. We must have either a press, or a proportionate number of straps with buckles at one end, which will serve to press the packets of blotting-paper between the two planks. We should also have a tin box, and a large book of blotting-paper, with a loose back, shut with little straps, and capable of being carried in the form of a knapsack. This book and box will serve, during a journey, for a temporary herbarium.

When we are stationary, we take the plants from the book or box, and place them in sheets of dry blotting-paper; between each sheet containing a plant, we must be careful to place two or more dry