_Published by the Royal Geographical Society in “Hints to Travellers.” 1921._] [Illustration: MEAN ANNUAL RAINFALL OF THE GLOBE. _Published by the Royal Geographical Society in “Hints to Travellers.” 1921._] II. PHOTOGRAPHY. _By J. THOMSON, formerly Instructor in Photography R.G.S._ Revised by J. MCINTOSH, _Secretary of the Royal Photographic Society of Great Britain._ The photographic camera should form an essential part of the traveller’s outfit, as it affords the only trustworthy means of obtaining pictorial records of his journey, and it is also helpful in making the survey of a new region, delineating its contours, its geological and botanical features, and ethnographical types of race. The camera and materials necessary for a journey may be readily obtained, so designed as to minimise space and weight, and in every way so perfectly adapted to the traveller’s needs as to ensure successful results in every variety of climate, and render the operation of taking a photograph extremely simple. It is necessary, however, that the traveller should make himself master of the principles involved in the production of a successful photograph, as he will have to depend on his personal effort in exposing and developing the plate, etc. He should also acquire a knowledge of the construction of the camera, to enable him to effect slight repairs when necessary. In selecting an outfit he must first decide upon the size of plate to be carried, and that need not exceed what is termed “half-plate,” 6½ × 4¾ inches; which is large enough for the best work. The smallest effective size for scientific work may be “quarter-plate,” 4¾ × 3¼ inches; in use in many hand-cameras. Negatives on this scale, if perfect, may be enlarged for book illustration, or printed as lantern slides. The two sizes given form a very complete outfit when extra weight may be conveniently carried. _Selecting a Camera._—The cameras should have bellows bodies of Russian leather which folds into small space, the woodwork must be well seasoned to prevent warping, or cracking under a hot sun. The framework should be metal-bound at the corners, and the camera fitted with a rising front and swing back, although the swing back is not indispensable. A reversible back (now universal) is of advantage, as it enables the operator to take vertical or horizontal views without turning the camera on its side. If the camera is fitted with a swing-front, the swing-back becomes unnecessary. The swing-front is in all ways preferable to the swing-back. [Illustration: BELLOWS CAMERA.]