28 



A RESPIRATION CALORIMETER. 



In order to facilitate the passage of the air current through the soda 

 lime and prevent channeling, a number of wire-gauze disks about 148 

 mm. in diameter and 8 mm. in thickness (cf, d, d, in fig. 13) are in- 

 serted in each cylinder so as to divide it into compartments. In filling 

 the cylinder the detachable cover is removed and a square of wire 

 gauze is inserted in the opposite end. A layer of cotton, d 1 , about 10 

 mm. thick is then inserted and a cover of wire gauze is placed above 

 it, these precautions being taken to prevent any of the soda lime from 

 sifting out. For the same reason a small thimble of wire gauze, T 

 (also shown in the extreme left of figure 13), is inserted in each 

 end of the cylinder. The cylinder is then filled with soda lime for 



about one-fourth of 

 its depth, one of the 

 wire-gauze disks 

 inserted, a second 

 layer of soda lime of 

 equal thickness in- 

 troduced, another 



FIG. 13. Cross-section of Carbon-Dioxide Absorber. Arrangement ,. , ,-, -, ,, . j 



in Cylinder, when Absorber is filled with Soda Mme, of Wire- dlsic added, a tlllm 



gauze Disks rf, d, d. Thimbles T, T, and Square S, with layer of layer of Soda lime, 



cotton rf 1 , are here shown. - ,, . . , , 



and then a disk, and 



finally a fourth layer of soda lime. A square of wire gauze, S, is then 

 put in, the rubber gasket and cover set in place, and the collar screwed 

 down tightly. 



Vise for tightening absorbers. It is absolutely essential that this joint 

 be tight, and as it is not safe to rely on the hands alone for this closure, 

 we resort to the use of a clamp and vise devised by our mechanician, 

 Mr. S. C. Dinsmore, and shown in figure 14. 



This device consists of two blocks of wood which offer a good sur- 

 face to grip the smooth cylinder. By means of two metal screws on 

 the top of the vise the two jaws are brought together and the cylinder 

 firmly held without distorting it. A wooden clamp which is readily 

 adjustable is then placed about the large collar C (see fig. 13), and by 

 means of this the end and the cap can be screwed down tightly against 

 the rubber gasket. 



Before removing the cylinder from the vise the tightness of closure 

 is tested by means of a water manometer and air-pump. With proper 

 precautions no difficulty is experienced in securing a tight joint. The 

 cylinders are weighed on the large balance shown in figure 21, being 

 suspended from one end of the balance beam by two loops of wire 

 fitting over the small tubes in both ends of the can. When charged 

 with soda lime they weigh approximately from 9.3 to 9.5 kg. 



