Chapter I: Mineralogy and Geology

Minerals are found either in regular and geometrical forms when they are called cristals, or in more or less irregular masses.

Among cristals there are some so situated that they can be separated without injury from the matter that envelopes them. Others compose salient groups; others are imbedded in rock.

Specimens of each of these three States should, if possible be procured; with regard to cristals enveloped in surrounding matter, particles of this matter should be detached with them (varying from 8 to 10 centimetres) so that the different minerals which accompany them may be observed.

Also portions of the masses composed of needles and fibres, or granulous or compact, having care to choose them fresh and free from those alterations that take place in these at the surface. The metallic mines should call the attention of travellers. They will observe if they are in parallel beds with the surrounding rocks or in clefts called veins which cross the bed. In detaching pieces from these mines care should be taken to leave around the principal metal portions of other metals which may be associated with them or stony substances which often accompany cristals.

It is to be desired for the progress of historic and technical mineralogy that pieces of stone should be selected which are most commonly used in the construction of public monuments and houses; and the most authentic samples should be procured of all the mineral substances employed in the useful and ornamental arts; such as sharpening stones, stones for ovens, stones to polish with and stones for potteries; having care to indicate the kinds of earth and stones which enter into the composition of each kind of pottery; whether minerals are indigenous or exotic, it must be particulary mentioned from whence they come.

If organic remains should be found in these earths, such as the bones of animals, shells, impressions of fish or vegetables, samples should be taken with care from these different bodies, leaving around them a portion of the earth or stone in which they are imbedded.

In case these earths should offer traces of volcanic origin, pieces will be taken of each substance ejected by the explosions, some of a stony nature, some as basalts, some as glass, some as obsidiennes, some as scaries, etc. For those which are prisms, care must be taken to remark the form of these prisms and the extent they occupy in the earth.

To each sample should be attached a ticket indicating the name of the country where they were found, the particular spot from which they were taken, the distance and situation of some neighbouring known town from it, the nature and appearance of the country and its elevation above the sea.

Wherever mineral waters shall be found care will be taken to fill a bottle, to cork and cement it closely.

Since those systems have been abandoned which restrained the observation of facts and comparison of those observations; since guessing of the origin of things has been renounced for studying their actual state; geology has advanced like other correct sciences. This advance has not only extended our acquaintance on the formation of the globe, but has also produced useful results for the arts. Notwithstanding we are far from knowing the various countries of the earth as we know Europe.

It is easy for those who visit these distant countries, above all the tropics, to procure us important ideas, and to send us productions, the examination of which can alone enlighten and furnish us informations on the nature of the soil in those countries and the general arrangement of the rocks which constitute the outside of the globe.

On all coasts and islands where vessels stop, travellers can land and procure objects with little trouble, which having little value in themselves, become instructive and interesting by the simple annotations which accompany them.

They can pick up on the borders of torrents pebbles which indicate the nature of the rochs from which they proceed. They will choose the largest and note their size, and also break some pieces,--also the small pebbles, having care to choose those of different appearances.

Wherever a rock is seen to rise, should it be in the water or land, it should be observed if it is all of the same substance or homogeneous or composed, or formed of different beds. In the first case a fragment must be detached, in the second case, they will observe the relative position of the beds, their inclination and thickness; and take a sample of each of the beds, and put the same mark on all the pieces coming from the same mountain, and a number on each to indicate the order of their position or reciprocal situation. If the person who procures these samples could make a simple sketch, to show the form of the mountain, the thickness and inclination of its layers, he would render an essential service.

In case the rock is an isolated one, it is useful to examine and sketch on both sides to be more certain of the inclinations of the beds.

It would be well to gather some sand from the bottoms of rivers; above all those which wash metallic dusts; but this sand must be taken as far from the mouth of the river as possible.

In some countries are found isolated masses to which the people attribute a singular origin; pieces must be taken; perhaps they are aerolithes; other may be transported by the revolutions of the globe.

In gathering fragments of rocks, mines, volcanic products and organised fossil bodies, the most essential thing is to mark well their latitude, that is to say the nature of the earth where they are found and their relative position to the substances which encircle them.

Basalt beds merit a particular attention, both as regards themselves and the kind of earth which surrounds or covers them. It must be noticed if they are divided in irregular masses, tables or prisms, and what is their arrangement. It be must remarked if they contain the remains of organised bodies, and care must be taken to take samples in their different states, also of the matter on which the basalt rests. It must be certain above all that there is no intervention of scorified matter, or beds of an earthy appareance, to which the Germans give the name of Wakke, and which are proved to be of volcanic origin. The rocks named trachytes by M. Haüy merit the same attention. They are distinguished above all by primitive porphyries, intermediate or secondary, by the absence of quartz and the presence of pyroxène or titanimmed iron.

Whatever may be the nature or age of the soil one sees, it is most important to collect samples of rocks the most common and most abundant which constitute the bulk of the soil: the study of the varieties of subordinate beds and accidental matters of all kind, should be secondary. In general the appearance of the constitution of the locality must be considered if one would proceed usfully to choose the samples destined to represent them; the choice would be easy if one would establish a rule never to quit a declivity, a mountain, a country even, without having made the section (geologically). We should add that these sections should be the principal object in the labours of the geological traveller.

Too large samples must not be taken, samples of 10 to 8 centimètres, by 3 or 4 of thickness, are sufficient. Larger samples must not be taken unless they contain the remains of organic fossils, such as animal skeletons. To pack these samples, they must be covered with fine paper; above this paper they will put the ticket or note of bearing or latitude, then a second fine paper that will be surrounded with tow, and all will be enveloped in grey paper. These samples will then be put in a box, placing them upright and in successive beds, as close together as possible, and filling the interstices with cut paper or tow, in a way to form a mass that nothing can derange. No space must be left between the last bed and the cover. The box must be tarred to avoid humidity.

The merit of geological collections being principally in the knowledge of local circumstances in which each sample is taken, it is indispensable to join to these collections well-arranged catalogues. They will repeat the numbers of the samples and directions written on the labels; all details should be inserted which may give a complete idea of the strata which have been observed, and sketches and drawings taken on the spot should be placed either in the margin or the body of the books. It would be well to have duplicates of the catalogues. One of them pressed between two pieces of board well tied, should be placed on the top of one of the boxes, the other should be adressed directly to M. Vattemare.