292 



SCIENCE 



[N. S. Vol. XXXII. No. 818 



distinguished from the modern steel "oifice 

 building" type. The walls are of very- 

 heavy masonry and bear the full weight. 

 The floors are constructed of steel girders 

 and vitrified brick arches, overlaid with 

 nearly a foot of concrete, and the roof is 

 made of steel framing, half-baked tiles and 

 heavy, graduated slate. Tests have shown 

 that there is little, if any, more vibration 

 on the main floor than there is on a heavy 

 pier especially constructed in the base- 

 ment, on the undisturbed earth and with- 

 out contact with the floor. One and a half 

 years' occupancy of the building has 

 proven the total lack of need of anti-vibra- 

 tion supports for apparatus sensitive to 

 mechanical disturbances. 



Apparatus is installed for either com- 

 plete or partial artificial ventilation, as 

 may be desired. The ventilating system 

 is broken up into four separate units. One 

 cares for the ventilation of the east wing 

 in which are the big lecture halls and the 

 laboratories for the general courses in 

 physics. The second provides for the west 

 wing, in which are placed the advanced 

 laboratories and most of the research 

 rooms. The third suffices for the main 

 part of the building in which are the small 

 lecture halls, the recitation rooms, the lib- 

 rary, some private rooms and the adminis- 

 trative offices of the departments. The 

 fourth section is connected with the chem- 

 ical laboratory, all dark rooms and the 

 storage battery rooms. The exhaust air 

 from the battery rooms is carried off in 

 lead ducts. Thus far it has been found 

 necessary to install fans and motors in 

 only the first and the last of the four parts 

 of the system. The general ventilation is 

 a marked success. 



The ordinary ventilating ducts of a few 

 of the research rooms have been supple- 

 mented by other ducts arranged to provide 

 for special drying of all the air admitted 



to those rooms. Any desired humidity 

 may be maintained in those rooms by 

 means of this device, to aid in electrostatic 

 studies and other lines of original work. 



The heating of the building is controlled 

 by a system of thermostats which enable 

 the temperature of any one room to be con- 

 trolled independently of everj' other room. 

 This feature of the structural equipment 

 has proven its worth in certain studies of 

 solutions, during which deleterious changes 

 of concentration with changes of tempera- 

 ture were prevented by the ability to keep 

 the room temperature constant, within very 

 narrow limits. 



The ventilating ducts and steam and 

 water and other pipes are distributed in a 

 manner which makes them at once acces- 

 sible and yet protected from injury. AU 

 the walls along the corridors are hollow 

 walls, with a fifteen inch interspace. Air 

 ducts and all pipes are carried in a pipe 

 tunnel, under the basement corridor floor. 

 Risers pass from this tunnel to the wall 

 interspace, and lead to the various rooms. 

 The space in the walls is sufficient to per- 

 mit a man to enter it to make repaire, 

 without damage to the walls, as has been 

 clone. At the same time, this space offers 

 an easy means of running special pipes, or 

 lines, from one floor to another, and from 

 room to room. 



A pendulum shaft, running from base- 

 ment floor to roof has been specially de- 

 signed for the reception of a Foucault 

 pendulum for showing the rotation of the 

 earth. The pendulum is now in course of 

 construction. Its ball is a lead sphere 

 weighing nearly 1,300 pounds. It ^vill be 

 supported by a steel wire from crossed 

 knife edges. It is hoped by this arrange- 

 ment to ensure a continuous plane vibra- 

 tion of thirty-six hours or more. 



The main machine shop is fully equipped 

 and stocked for either the production of 



