CALORIMETER LABORATORY. 7 



bed calorimeter with the front removed and the rubber hose connections as 

 carried from the absorber table to the bed calorimeter are shown. At the 

 extreme left is the balance for weighing the absorbers. Above the chair 

 calorimeter can be seen the balance for weighing the subject, and at its 

 right the galvanometer suspended from the ceiling. 



The west side of the laboratory at the moment of writing contains the 

 larger proportion of the apparatus. On the east side there exist only the 

 balance for weighing oxygen cylinders and an unfinished * large calorim- 

 eter, which will be used for experiments of long duration. A view taken 

 near the front end of the bed calorimeter is shown in fig. 5. At the right, 

 the structural skeleton of the large calorimeter is clearly shown. Some of 

 the copper sections to be used in constructing the lining of the calorimeter 

 can be seen against the wall in the rear. 



At the left the balance for weighing the oxygen cylinders is shown with 

 its counterpoise. A reserve oxygen cylinder is standing immediately in 

 front of it. A large calorimeter modeled somewhat after the plan of 

 Sonden and Tigerstedt's apparatus in Stockholm and Helsingfors is planned 

 to be built immediately back of the balance for weighing oxygen cylinders. 



HEATING AND VENTILATING. 



Of special interest in connection with this calorimeter laboratory are the 

 plans for maintaining constant temperature and humidity (fig. 6). The 

 room is heated by five steam radiators (each with about 47 square feet of 

 radiating surface) placed about the outer wall, which are controlled by two 

 pendant thermostats. A certain amount of indirect ventilation is provided, 

 as indicated by the arrows on the inner wall. The room is cooled and the 

 humidity regulated by a system of refrigeration installed in an adjoining 

 room. This apparatus is of particular interest and will be described in 

 detail. 



In the small room shown at the south side of the laboratory is placed a 

 powerful electric fan which draws the air from above the floor of the calo- 

 rimeter laboratory, draws it over brine coils, and sends it out into a large 

 duct suspended on the ceiling of the laboratory. This duct has a number 

 of openings, each of which can be controlled by a valve, and an unlimited 

 supply of cold air can be directed to any portion of the calorimeter room 

 at will. To provide for more continuous operation and for more exact 

 temperature control, a thermostat has been placed in the duct and is so 

 constructed as to operate some reheater coils beneath the brine-coils in the 

 refrigerating room. This thermostat is set at 60 F., and when the tem- 

 perature of the air in the duct falls below this point, the reheater system 

 is automatically opened or closed. The thermostat can be set at any point 



* As this report goes to press, this calorimeter is well on the way to completion. 



