THE CALORIMETER SYSTEM AND MEASUREMENT OF HEAT. l6l 



To support the man in a comfortable position while being weighed, 

 we have provided a chair which can be suspended from the rod of the 

 weighing apparatus. A hard-wood folding-chair, which has been in 

 use regularly inside the chamber for a number of years, was utilized 

 for this purpose. This is shown in figure 46. 



A chain (or at present a phosphor-bronze tiller rope) is fastened to 

 the back of the chair and to the legs in such a manner that it can be 

 suspended. To spread the rope at the front end of the chair seat, two 

 oak blocks through which the rope passes were hinged under the seat. 

 . A piece of gas-pipe with a hook serves to suspend the chair and act as 

 a spreader at the top. By using this spreader arm more space is given 

 between the chains for the arms and shoulders of the subject. The 

 chair is hooked into the spreader arm in such a position that during the 

 weighing the subject faces the window. 



The upper end of the suspension rod for the weighing system passes 

 through a hole in the hanger on the platform balance. Two nuts are 

 screwed on the end of the rod, the upper one of which serves as a lock- 

 nut. It is thus possible to raise or lower the rod by adjusting these two 

 nuts. The rod is so adjusted that when the rubber stopper is removed 

 from the fiber tube it swings perfectly free, and there is no danger of 

 touching the side of the fiber tube. When the stopper is put in place, 

 the suspension rod slips freely up through the hole in the hanger, and 

 the friction of the rubber stopper in the fiber tube holds the rod up in 

 place. It has been found by experience that the taper on the stopper 

 is such that it can be inserted in the fiber tube and support the rod 

 above it without any danger of slipping out. When not in actual use 

 for weighing, the stopper is always crowded well into place. 



On the end of the suspension rod there is simply a large iron ring, 

 and it was found inconvenient to suspend everything from this ring 

 without any intervening adjustment ; consequently a hanger consisting 

 of a regular gas-fitter's cross was attached. Into opposite sides of two 

 of the openings in the cross two half -inch pipes (16 mm. internal diam- 

 eter) are screwed. These pipes are 14 cm. long, are open at the end, 

 and have a 7 mm. hole drilled on the under side 8 mm. from the open 

 end. A stout iron hook is screwed into a hole drilled in the side of the 

 cross, and can be inserted in the ring on the end of the suspension rod. 

 When suspended in this way, the cross lies parallel to the top of the 

 chamber. In the other two arms of the cross, reducers and smaller 

 pipes 1 8 cm. long and 10 mm. internal diameter are screwed and are 

 used for suspending the absorbing system. 



Weighing the absorbing system. In weighing the absorbing system as 

 was formerly done by the use of spring balances, the accuracy was not 



I IB 



