N .VH67. 



Blackboard Frames. 



27 



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50165. 1:H. 



50 166, 50 181. 1 : -22. 



r>o.!65. NEW! Water Air Pump and Water Jet Blower, mounted on one board, Figure, - s. d. 

 consisting of W a t e r 'A i r P u m p X o. 50,129 (with water bag and metal vacuum 

 gauge of 100 mm scale diameter) and Blow e r Xo. 50,144 with 1 refuse trap, 1 screw 

 down tap each for the pump and the blower and 1 pressure gauge for showing the water- 

 pressure 7. 5. 



The board is 200 cm high and 48 cm wide. The nets of the waste trap may be removed for 

 cleaning. 



Blackboard Frames. 



.~ni. Kit";. Blackboard Stand with Cupboard Substructure (Figure), constructed of pitch pine, | 



with 1 blackboard 1.8 m long and 1 m high 10. 15. 



The blackboard is of deal; it consist* of frame and pannellings and is covered on the front with 

 black linoleum; it has an even, dull black, non-reflecting writing surface, is suspended on gut strings, 

 balanced by iron weights, and can easily be moved in an up-and-down direction. The body of the 

 frame forms a cupboard having 3 double doors and 3 drawers for taking chemicals and the like, and 

 an oak slab at the height of the table. 



The blackboard frame is arranged in such manner that the sliding window of the stink cupboard 

 is placed behind the blackboard, and on the room being darkened the blackboard screens off the light 

 passing through the window of the stink cupboard. 



50,167. --The preceding, with 2 blackboards 12. 5. 



In this construction one blackboard balances the other, so that a stink cupboard placed in the 

 wall behind the frame is not accessible. If it is desired to have a stink cupboard behind the frame, 

 the 2 blackboards must be balanced independently of each other. If this is necessary, the price of the 

 frame is increased bv about 1. 5. 0. 



Cl. 5331, 36 



