292 REPORTS ON THE STATE OF SCIENCE, ETC, 



sufficient space which cannot be encroached upon in the dark should be reserved 

 round the lantern for easj' operation. 



It might occasionally happen that the whole of a small room was required for an 

 audience with a vacant room adjoining. In such circumstances a hole might be made 

 in the end wall for the lantern objective and the lantern and operator placed in this 

 adjoining room. 



APPENDIX. 



Specification of a 16 7nm. Projector. 



The machine should be of sound construction as generally accepted in cinemato- 

 graph apparatus. 



The machine must be rigid under operative conditions. 



All parts subject to wear should be so designed that replacements can be obtained 

 and fitted to the machine by the operator. 



The 16 mm. standards as fixed by the Society of Motor Picture Engineers should 

 apply, and the machine must effectivelj' operate film that has shrunk 1-5 per cent, 

 below the standard of new film. English standard dimensions should be used and the 

 decimal system used to show limits. 



Where British Engineering Standards Association standards applj' they are to be 

 used, and all screws and threads are to be of British Association Standards. A hand 

 drive should be incorporated. 



All terminals or connections in the electric circuit are to be enclosed by a suitable 

 insulating material and the machine ' earthed ' by a third wire in the ' leads ' when 

 intended for use on a circuit over 50 volts. _ 



A switch for the motor and one for the lamp should be fitted in a convenient ■ 

 position, and where this is intended for over 50 volts ' earthed ' switches must be ■ 

 installed. 



A suitable means of holding any one ' frame ' or picture stationary in the gate for 

 five minutes, without damage to the film from the heat of the light source, is necessary. 



The metal parts of the gate that are in contact witli the film should be either of 

 lustless steel or a hard non-ferrous metal. 



Simplicity of threading the film into the machine is very essential in order to avoid 

 delay between reels. 



Where possible, dust-proof lubricators should be used for parts requiring lubri- 

 cation, and should be of such construction or colour as to define its use. 



A means of winding film from one reel to another should be incorporated in the! 

 machine. 



The general finish of the machine should be a matt black enamel, and all plated! 

 parts should be dull plated, with the object of avoiding any reflection in the eyes of] 

 the operator. 



A strong dust-proof cover of wood or metal to enclose the whole of the machinel 

 and motor should be part of the equipment, and the cover should be fitted A^ith 

 suitable handle and fasteners for hand transport. In the lid of such cover, or otherl 

 suitable place, should be fixed an instruction chart on the oiling and operating of thel 

 machine, and means for holding securely two film reels. 



Each machine should have a serial number for reference purposes. 



