66 A RESPIRATION CALORIMETER. 



and consequently at this point the calculation converting the weight 

 in grams of nitrogen to liters is made. This calculation is based on the 

 relations between the weights and volumes of gases as discussed on 

 page 82, and is here simplified by adding the logarithmic factor .90078 

 to the logarithm of the weight of nitrogen in grams. It is thus seen 

 that the volume of nitrogen admitted with the oxygen in this case was 

 o. 54 liter. On the blank a space is left for several calculations of this 

 nature, as it frequently happens that more than one cylinder of ox3'gen 

 is used during an experimental period. The oxygen is always admitted 

 as long as it will flow from the cylinder, and even in ordinary rest exper- 

 iments it is rare that the last of a cylinder of oxygen is coincident with 

 the end of an experimental period. During excessively hard-work 

 experiments, several cylinders may be used. In case more than one 

 cylinder is used, the weights of oxygen and liters of nitrogen are footed 

 up at the bottom. Furthermore, a slight constant correction, amount- 

 ing to 0.04 gram of oxygen (see p. 74) , is made for certain alterations 

 in volume, due either to interchange of air through the food aperture or 

 opening and closing of mercury valves, which correction, for the sake 

 of convenience, is made on this sheet. During this period we find that 

 the total amount of oxygen admitted is 46.07 grams. 



It is thus seen that, when no reference is made to the variations in 

 composition of the residual air, the amount of carbon dioxide and water 

 eliminated per given period and the amount of oxygen absorbed may be 

 determined from the weights of water and carbon dioxide taken up by 

 the absorbing system and the weight of oxygen admitted from the steel 

 cylinder, with due allowance for the accompanying weight of nitrogen. 



RESIDUAL ANALYTICAL DATA. 



The data for the two residual analyses are likewise recorded side by 

 side on this sheet. They include the amount of air passing through 

 the meter, the temperature of the meter, correction for the thermometer 

 used in the meter, pressure on the meter expressed in millimeters of 

 water as read on the manometer, its conversion to millimeters of mer- 

 cury, and the gains in weight of the U tubes used for analysis. Beneath 

 the record of these data are placed the temperature records and the 

 position of the pans. When the thermometer has a correction, the 

 corrected temperature is placed at the right of that observed. In this 

 instance the thermometer had a zero correction. Pan No. 2 was empty, 

 and in this position it is assumed that 2.5 liters of air are inclosed by this 

 pan, diaphragm, and pipes. (Seep. 41.) The pointer on the wheel of 

 pan No. i stood at the graduation 575, and from a previously prepared 

 table it is found that at this position the rubber diaphragm, pan, and 



