January 23, 1903.] 



SCIENCE. 



135 



be cooled will be blown over these coils of 

 pipe. On one side of this cold room, 

 space will be reserved for placing appa- 

 ratus which it may be desired to cool, or 

 to perform an experiment at the low tem- 

 perature of this room. The hall in the 

 center of the basement, which is ten feet 

 wide, leads directly into the tunnel, which 

 is twelve feet wide and on the same level. 

 This tunnel leads directly into the base- 

 ment of the physical laboratory, located 

 about 175 feet to the south. The heating 

 chamber will contain two banks of steam 

 coils, a larger or 'heating' coil, and a 

 smaller or 'tempering' coil. Air passing 

 through the first is drawn into fan No. 1, 

 while air passing through the second goes 

 along the direction of the dotted line into 

 fan No. 2. "When it is desired to cool the 

 air, the latter is diverted and goes along 

 the course of the solid arrows through the 

 cooling chamber to fan No. 2. Each fan 

 has a double discharge, about three fifths 

 of the air passing out of the upper out- 

 let, toward the south and through the 

 tunnel to the physical building, and two 

 fifths going through the lower outlet under 

 the floor of the corridor, to be distributed 

 to the flues of the mechanical building. 

 These blowers are operated by electric 

 motors, and may be driven at different 

 speeds. 



The gas machine will produce a gas from 

 gasoline better suited for furnace work, 

 hardening, tempering, etc., than ordinary 

 illuminating gas. This will be piped to 

 all the laboratory rooms. 



The large room on the first fioor, just 

 above the boiler room, is the instrument 

 shop. This is an important feature of 

 any physical laboratory where research is 

 carried on. Four or five lathes of differ- 

 ent sizes and styles, a universal milling 

 machine, shaper, drill press, grinder, cir- 

 cular saw and other machines will be in- 



stalled, and a complete equipment of hand 

 tools provided. The stock room, drafting 

 room, and pattern shop belong to the in- 

 strument shop. 



At the instrument room on this floor, 

 instruments for testing will be received and 

 shipped, and apparatus and supplies of the 

 bureau will be received. The heavy cur- 

 rent testing laboratory will be provided 

 with eight large storage cells, which, when 

 joined in parallel, will give a current up 

 to 20,000 amperes. They will be charged 

 in series, and may be discharged singly or 

 together in any combination. Shunts and 

 recording wattmeters for heavy current 

 will be tested here. The adjacent room, 

 which is directly over the alternating gen- 

 erator, will be used for testing alternating- 

 current instruments. This will sometimes 

 include an examination of their behavior 

 on different loads, at different tempera- 

 tures, with currents of different fre- 

 quencies, different power factors, and dif- 

 ferent wave shapes. Complete specifica- 

 tions of these factors will be supplied when 

 desired with the results of the test. 



Immediately above this room on the sec- 

 ond floor, is another electrical laboratory 

 room for alternating- and direct-current 

 experiments, and the magnetic properties 

 of iron, study of transformers, condensers, 

 and cables, under relatively high electro- 

 motive forces. Room 24, adjacent, will 

 contain transformers for obtaining still 

 higher alternating voltages for testing in- 

 sulation resistances ; and instruments for 

 measuring alternating voltages up to 50,- 

 000 volts or higher will be tested here. 

 Room 25 will contain a storage battery of 

 small cells giving potentials up to 20,000 

 volts and currents up to 1 ampere at this 

 voltage. Rooms 22 and 23 are to be used 

 for the photometric study and calibration 

 of incandescent lamps, gas lamps, Nernst 

 lamps, etc. Immediately above, on the 



