196 



Reports on Special Researches 



The charging-board is shown to the left of Figure 4 of Plate 9. The 2 horizontal bus- 

 bars in the center of the photograph are connected through the ammeter, circuit-breaker, 

 and charging-rheostat to the charging-switch at the bottom of the figure. The voltmeter 

 is, of course, connected to the bus-bars. The short vertical bars are connected to the 

 terminals of the groups of cells above referred to and to the double-pole switches shown. 

 The latter serve to connect or to disconnect them from the corresponding vertical bars of 

 the distributing-panel. The single-pole switches are for throwing the groups in series, 

 and it will readily be seen that a large nimiber of arrangements of the cells may be made in 

 series or in parallel, both for the purposes of charging and distribution. Further, by a suit- 

 able combination, voltages may be obtained in multiples of 6 ranging from to 120 volts. 

 The fact that the groups may be entirely disconnected from each other is of advantage in 



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SCALZ. IM ME.TEKS 



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l''iG. 6. Plan of First Floor of Main Building. 



enabling them to be used entirely independently; thus, two different portions of the battery 

 may, for example, be used simultaneously, each having an earthed terminal. The horizontal 

 bars of the distributing-panels are, of course, joined to the laboratory conduits, and suit- 

 able connections are provided for connecting them to the appropriate vertical bars. The 

 motor-generator is designed so that by the field control alone a stable voltage range is 

 possible from 90 to 60 volts. This enables the two 30-cell batteries to be charged in 

 parallel without waste of power in the charging-rheostat. 



The first floor (Fig. 6) is devoted primarily to the experimental work of the labora- 

 tory. There are 3 large laboratory rooms, 2 small laboratory rooms, chief physicist's room, 

 chemical laboratory, and dark room. Each of these is provided with hot and cold water 

 and a number of dust-proof power receptacles 3 feet 6 inches above the floor for alternating 



