CO885-(21-23) — Page 484

PUBLIC RECORD OFFICE

Reference :-

mmmmiii C.O. 885

22 PUBLIC RECORD OFFICE, LONDON

ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH-NOT TO

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structures are present, it is desirable to indicate on the specimen its original position in the rock; for this purpose the symbol or repeated in different parts of the specimen may be employed, the cross line being horizontal and the arrow being inclined downwards but not necessarily vertically. The arrow with two barbs should be employed when the mark is on the actual dip slope. In this case the amount and direction of the dip may be also inscribed if desired.

Some collectors, instead of writing on the corner of the wrapping paper, use a separate slip of paper which is folded twice and then wrapped up with the specimen, with which however it should not be actually in contact.

Cotton, linen, or manilla bags are sometimes used instead of paper and may have a distinguishing number printed on the outside. This, however, is easily obliterated with rough usage. A better plan is for the number to be engraved on a metal dise with a perforation by which it is threaded on the string employed to tie up the bag. In any case a folded slip of paper, with the particulars already mentioned, should be placed in the bag, which should be sewn up or tied round with string close to the specimen so that the latter cannot shift its position.

Tie-on labels should be provided in case paper or bags run short, but wrappings of some sort to protect the specimens and prevent them from rubbing against each other should never be dispensed with.

If the specimens are likely to be stored in a place where termites (white ants) or other destructive insects may have access to them, the wrappings, bags, paper slips, and labels should be protected by previous soaking in a weak solution of Corrosive sublimate (mercuric chloride).

The specimens collected are usually carried, unless specially delicate, in a satchel or haversack, but at the end of the day's work they should be carefully parked in such a manner that there is no play between them in transport. If they are liable to be subjected to rough usage, for instance, wetting in the rainy season or in crossing streams, it is wise to unwrap every specimen at the end of the day and paint on each the date, the distinguish- ing number or letter, and, if time permits, the locality from which it was obtained. Some point should be chosen where the painting will not spoil the look of the specimen. Black or red paint should be used. Unless the specimen is smooth and white or pale in colour so as to furnish a contrast to the paint, white ground should be first painted. Water colours may he employed and are indeed to be recommended, provided that the writing is covered when dry with transparent varnish. A solution of sealing wax in methylated spirits is recommended as a good paint which will not wash off, and Aspinall's Enamel has also been used but is apt to peel off in hot weather. paints have the additional advantage of being insect proof.

When travelling rapidly there may not be time at the moment of collection to label and wrap up specimens properly. The best course in that case is to place them in separate pockets or in

a

Most

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separate compartments of the haversack, and at the same time make a written note of the whereabouts of each. This course should only be regarded as a temporary and exceptional measure, and the usual procedure should be followed at the first halt. In no case should the memory be trusted with regard to the identity or locality of a specimen, nor should two specimens be allowed to rub against one another in the same receptacle.

X.

MINERALS AND METEORITES,

Every effort should be made to obtain pure and uniform specimens of minerals for scientific investigation. For this purpose comparatively small amounts, two ounces or even less, will suffice, but larger specimens should be collected when circumstances permit. Good crystals are of great value for the measurement of the angles between their faces and determination of their optical characters as well as for analysis, for they are usually purer than imperfectly crystallized material. Size is not of so much importance as smooth lustrous faces, A crystal which is free on all sides, or on all except one, is better than a crystal which is almost completely embedded between others. The scientific value of a crystal is also greater the larger the number of faces it shows. The best crystals are usually found in small rock cavities. Specimens of twin crystals, that is to say, those which are symmetrically joined together, should also be collected. It is usually better to break off with the crystal a portion of the rock to which it adheres.

Crystals should be very carefully handled; even perspiration from the finger may tarnish the lustre of a face. Delicate crystals should be wrapped first in soft tissue paper, then succes- sively in cotton wool and newspaper, and finally packed in a small box, which may be placed with others in a larger receptacle. These precautions may be somewhat relaxed with less fragile specimens but all should be embedded in soft material and packed sufficiently tightly to prevent them shifting in the packing. Many of the recommendations given later with regard to fossils also apply to minerals.

Meteorites occasionally fall in all parts of the globe, and any story of stones having dropped from the sky whether recently or in past times should be carefully investigated. Meteorites consist sometimes of grey stoney material with, as a rule, particles of metal scattered through it, and a thin black crust, and sometimes of iron alloyed with nickel. Indeed, any block of iron which does not appear to be of artificial origin is probably meteoric and should be forwarded for examination to a competent authority on the subject. Meteorites should be carefully packed and as far as possible kept dry. For this purpose a meteorite may be painted with melted paraffin wax, and a small box containing quick-lime and perforated with minute perforations may be placed in the case in which the specimen is packed.