THE EASEL.
One modification of that shown in Fig. 422 consists of an arrangement of rails • tripping over them in the dark. Instead of having the adjustable carrier, the easel itself may be made adjustable either fur raising or lowering or side movements. A novel and convenient form of easel is that shown in Fig. 430, which, besides a raising and lowering adjustment, is pro vided with a swing movement, often use ful for architectural subjects with dis torted lines. The enlarging table and screen shown by Fig. 431 possesses prac tically every imaginable movement for securing speed and comfort in enlarging, and embodies many ingenious principles.
shown in Fig. 42.2 remains intact, but over the reflector is suspended a powerful arc lamp enclosed in a white lined hood ; this throws parallel rays on the reflector in a similar way to that which occurs with daylight. The disadvantage of such 1111,1/1, iLn mit o, which is largely used among pro ial workers. Owing to the loss of
light the reflector it is necessary that the illuminant should be ex_ ceedingly powerful ; this means con siderable waste of light, or else long exposures and difficult focussing. Passing from this, one comes to the various methods involving the use of a condenser. With these far less 'Hit may be used ; even the humble paraffin lamp can be employed to make very successful experiments. Each worker has his own particular fad as to the best illuminant, but either paraffin, incandescent gas, limelight, or the electric arc can be employed. The ordinary coal gas flame and the incandescent electric are unsuitable. Where the source of light is small, such as in the 'case of light or the electric arc, a much sharper image is produced ; but as this sharpness