FILM-PACKS, ETC.
with slides of the single variety, holding one plate only, and allowing its introduc tion by a hinged door at the back. Some of the old-fashioned cameras are supplied with solid dark-slides, in which the plate is inserted by withdrawing the shutter, and retained in position by movable metal catches at the corners or sides. This is a bad form, for if the catches should happen to work loose and slip, the plate may fall out when the shutter is withdrawn. In dark-slides of the American pattern the plate is inserted by pressing a lever at the bottom, which falls back and allows the plate to drop into position (see Figs. 124 and 125). Metal dark-slides are very con venient for touring purposes, being re markably light, and taking up little room. Cheap and light clark-slides made of card board are also obtainable, and are useful in an emergency, or for the construction of experimental apparatus. How to make There are various patent contrivances by which a number of cut films may be intro &Iced together into the cainefra, without the aid of a dark-room, and exposed in succession. Among these may be men
tioned the " Ii ajar " changer and the • " Premo " film-pack, which are both highly ingenious in principle and satisfactory in operation. The convenience of being able • to carry about any number of films ready for exposure as desired is certainly one which must appeal to the tourist photo grapher. It should be mentioned, how- 1 ever, that an adapter, or a slight altera tion of the camera-back, is required before these contrivances can he used with ap- I paratus not specially made for them or to which they have not been fitted. The " Hajar " changer can generally be ad justed to any camera without alteration being necessary. There are other ar rangements for carrying a number of flat ins, but these generally require a special mera or holder, although, as a rule, very nvenient and satisfactory.