PHOTOGEAPHY. 
53 
averages 3 lbs. per dozen, and, as the traveller should take with him from 
half a gross upwards, it is evident that the chief weight of the necessary 
photographic impedimenta is solid glass. This weight may be much 
diminished by using flexible celluloid films as the base for the sensitive 
gelatine film. Without doubt, glass plates yield the best results; but 
celluloid films in the smaller r sizes, up to 7i x 5, approach very nearly to 
glass in many respects, and have the advantage of being one twelfth the 
weight and not liable to breakage. They are exposed in the same slides, 
and require the same treatment as glass plates. 
As, however, the production of good film negatives requires consider¬ 
able skill and nicety of manipulation, it will be well for the traveller who 
has not been able to attain expertness therein, to provide himself with 
Bellows Camera. 
glass plates in addition to flat celluloid films. It would simplify matters 
and greatly lighten the burden of the traveller if rolled and flat films 
could be trusted to do their work satisfactorily under all conditions of 
atmosphere and climate, but they cannot be so trusted, for reasons I will 
note later on. The following list comprises all the apparatus necessary 
for taking photographs on dry gelatine-coated glass plates or celluloid 
films. 
1. A camera .—This should be, for the larger cameras, of the bellows- 
bodied form, of best mahogany, thoroughly well seasoned, and it is very 
convenient for it to be fitted with what is known as a reversible back. 
It should have a movable front, capable of shifting both vertically and 
horizontally; and a swing back; that is to say, the frame carrying the 
focussing-glass and sensitive plates must be capable of turning on a 
