8 Equipment of the Class Rooms. 



desirable. In consideration of the arc lamp for the projection lantern and for experiments, as well 

 as for arc light illumination, a pressure of about 65 volts is the most suitable. Direct current should 

 be given the first consideration in selecting the kind of current. Supposing the pressure of the central 

 station supplying direct current to be high, e. g., 220 or 500 volts, and if it be desired not to work 

 continuously with large energy-losses, a direct current-direct current transformer should be 

 installed, transforming the network voltage down to 65 volts. If it is wished to have alternating 

 and three phase as well as direct current available, a direct - alternating - triphase trans- 

 former is used in conjunction with a direct current network, and a triphase-direct-alternating current 

 transformer if the supply is three phase. 



We shall be pleased to give all advice and submit the necessary drawings relative to the lay- 

 ing of the leads and piping lines of every description the gas and 

 water pipes, the water outlet in the floor, the arrangement of water 

 air pumps and water jet blowers, the fixing of draught chambers 

 and channels for draught cupboards, the fitting of window darken- 

 ing devices, the galvanometer suspension, etc. - - in fact in connection with 

 the whole equipment. With this object, we would ask that the constructional plans of the rooms in 

 question should be sent to us at the proper time. 



If desired, we shall also be pleased to send an engineer out to discuss the question 

 of the fittings and their erection on th spot with clients. 



It is advisable to allow us to carry out the preliminary work before building commences. 



The fact that we are in a position to make thoroughly reliable proposals is vouched for by the 

 very large number (more than 750 up to the present) of higher grade schools, science and art schools, 

 universities, technical high schools, etc. for the physical and chemical class, preparation and collection ~ 

 rooms of which we have supplied fittings and apparatus. ~ 



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