l60 REPORTS O^ INVESTIGATIONS AND PROJECTS. 



special ventilation of the hoods and toilet rooms. The main ventilating sys- 

 tem was installed with special reference to the needs of a physiological and 

 chemical laboratory, and for ordinary uses it is a natural gravity system. 

 With the increase of the number of workers in the laboratory and the greater 

 need for special ventilation, a powerful electric blower which is installed in 

 the pent-house on the roof may be put in operation. This blower can be started 

 and stopped from the machine-shop in the basement. A similar power blower 

 may be used with the ventilating system connected with the hoods. 



Each laboratory room is supplied with hot and cold water, high-pressure 

 steam, electricity at no and 220 volts (direct current), gas, and compressed 

 air, and hoods for the removal of noxious fumes are planned for each lab- 

 oratory. 



Calorimeter Laboratory. — For the most satisfactory operation of an appa- 

 ratus as complicated and as sensitive as the respiration calorimeter, a special 

 type of room was constructed. The room is 47 feet long, 33 feet wide, and 15 

 feet high. By means of two large girders in the third floor, it was made pos- 

 sible to suspend the ceiling of the calorimeter room and thus eliminate any 

 piers or columns in the center of this room ; thus the greatest freedom is af- 

 forded in the construction and assembling of the various parts of the respira- 

 tion calorimeter and its accessory apparatus. 



As in other calorimetric investigations, a constant-temperature room is 

 highly desirable. Accordingly, provisions were made for permitting temper- 

 ature control in this large calorimeter room. To this end, the windows and 

 transoms are all double, the doors either of refrigerator construction or 

 double, with air-space between, and in cold weather the room is heated by 5 

 steam radiators under control of 2 pendent thermostats, set at 70° F. Of 

 special interest is the arrangement for cooling the room during the summer 

 months, when temperatures above 72° or 73°, particularly with the high hu- 

 midity experienced during summer weather, are inimical to successful experi- 

 menting with the respiration calorimeter. The temperature-control and 

 heat-measurements of the calorimeters depend in large part upon an elaborate 

 system of thermo-electrical elements and electrical resistance thermometers. 

 Hence it is very important to maintain a low humidity in the air of the lab- 

 oratory to avoid disturbances of the electrical connections. 



Cooling during the warm weather and drying the air are accomplished at 

 the same time by causing the air of the room to be forced by a blower over 

 several series of brine coils, through which cold brine is forced from the 

 power-house mains. The excessive moisture in the air is thus deposited on 

 the brine coils and an unlimited supply of cold dry air can be returned to the 

 calorimeter laboratory. Provisions are made for using alternate series of 

 coils and thus allow the removal of accumulated moisture. The system has 

 been tested and it works to complete satisfaction. 



