The Art of projection and complete magic lantern ... - Yesterday Image

T02together is a dreadful affair, if one of the poles is left behind, the lanternistis hors de-combat, and even when it is up has no solidity.The only recommendable frame up to 12 feet is the "Articulosus " (Fig.54) it has no pieces to join together or parts to be left behind, brass knucklejoints hold the whole frame complete in two halves as Fig. 56. After settingout each half of the frame, and placing the brasspin through the holes inthe top knuckle joints, to hold the top rails stift", run the whole of the ringsof the screen over one side of the top rail, this done, join the two halvestogether by means of the bayonet catch, and distribute the rings equallyover the pole or rod, slipping the ring of each end over the end of thebrass work of the frame.If not sufificiently wide for this purpose, fastena piece of string to the last ring of each end, and tie over the corner ofthe brass work, in a similar manner, raise the frame with screen attacheda little at the time, by means of the central pole, and as the rod israisedfasten the tapes of the side of the screen to same. When the screen isat its full height, the bottom corners of the screen are tied to the stays,going across the A shape sides in the cross bar of the A as it were, if thisis not sufficient to draw the screen tight, fasten a cord from the eyeattached to the bottom of the upright rod, passing it down underneaththe cross bar or stay to the other side,under the stay or cross bar, and upto the other rod, fastening off at the screw eye. The screen may thenbe fastened at the bottom and sides to this cord, and may be made astight as a drum.When dealing with a large frame from 16 to 20 feet, an entirely differentprinciple is necessary. That which will stand firm and rigid at 12 feet,when lengthened to 16 or 20, becomes quite flimsy and inadequate, tohold the extra strain, a resource must be made to guy ropes and a firmerbasis.This necessisates stronger poles and heavier castings for the anglepieces. With these larger sizes, it is a complete frame in itself, with all foursides. Fig. 56. When this is firmly placed, and guyed to the extending feetor base, the screen is pulled up by a cord running on wheels at the topcorner, the tapes of the screen are fastened to the woodwork of the frameat all sides including bottom. All this cannot be done without weight, fora 20 feet frame, the woodwork must be solid and firm with brass castingsof a substantial quality. Bamboo is very portable, but lacks the soliditynecessary for large frames, for smaller sizes there is a slight gain inweight, over ordinary deal rods.In most large halls, a nail can be found on which can be hung a pulleyblock, such as is used in tent and awning work. A strong cord, (blind cordis the best,) is passed through the ring at top of the screen, and fastenedoff tightly at each end, this cord is then passed through the pulley block