No. 50425. 



Blackboard Stands. 



89 





03 



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50 425. 1 : 22. 



50,425. Blackboard Stand with Projection Screen, Platform and Lecture Desk, as supplied to Priee on 

 the Senckenb'erg-Mnseum, Frankfort-on-the-Main (Figure) appli- 

 cation 



The blackboard stand is of pitch-pine, it carries 2 blackboards of 2 m length and 1 m height. 

 The boards are of poplar covered with slate, are suspended on stout gut cords and can easily be moved 

 up and down, one balancing the other. The projection screen is 2 m wide and 2 m high; it is placed 

 under the cornice of the blackboard stand and shielded from dust, being rolled up and down by a 

 cord arrangement. The screen is made for reflected light, of specially prepared fabric with dead white 

 non-reflecting surface, being characterised by its great durability and showing up the image in a beauti- 

 ful manner. The Lecture Desk is moved from the platform while lantern demonstrations are going 

 on, being mounted on castors to facilitate this. It may also be used when placed alongside the plat- 

 form, when it faces the audience obliquely to allow of the lecturer observing the image. 



For other Blackboard Stands see pp. 2729, and for further Projection Screens, see List of Projection 

 Apparatus. 



C\. 4200. 



