118 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



cally all instances corrected our periods for changes in the residual 

 analysis, the analyses being for the most part made with the Sonden 

 apparatus. Similarly, in check tests, in which the carbon dioxide was 

 admitted to the large chamber from a steel cylinder and the carbon 

 dioxide was determined in short periods, the residual analysis played a 

 very important role, for the introduction of the carbon dioxide into the 

 chamber was extremely irregular. On the other hand, with a group of 

 normal men or women pursuing a certain definite procedure such as 

 reading or walking, the carbon-dioxide production becomes very regu- 

 lar after a very short time. In certain instances the accuracy of the 

 Sonden apparatus for finding the residual carbon dioxide was deter- 

 mined by having no ventilation in the chamber, analyzing the air 

 at the start, introducing a certain amount of carbon dioxide, analyzing 

 the air at the end, and comparing the carbon-dioxide content of the air 

 at the beginning and the end of the test. This type of check also gave 

 most gratifying results whenever used. 



The humidity and temperature of the air inside the chamber were 

 determined by the wet and dry bulb thermometer, easily read through 

 the glass window. The method of calculation is indicated in detail 

 for a single experimental period in table 4, and the summary of results 

 of an entire night experiment in table 5. 



Table 4. — Typical calculation of a period with the group respiration chamber {12^32^ — 1H>2^ 



a.m. Oct. 7, 1917.) 



Calculation of residual carbon dioxide in the chamber.* 



Observations. At 12i'32°' a. m. At l''02» a. m. 



Barometer 768.60 mm. 768.75 mm. 



Temp, barometer 20.0°C. 20.0°C. 



Temp, dry bulb 18.7°C. 18.9°C. 



Temp, wet bulb 15.3°C. 15.4°C. 



Per cent CO2 0.191 0.195 



Logarithms. Logarithms. 



(p-e)/760 9.99725-10 9.99733-10 



l/l-|-0.00367< 9.97117-10 9.97088-10 



Volume of chamber 4.63925 4.63925 



Per cent CO2 7.28103-10 7.29003-10 



Liters to grams 0.29320 0.29320 



Total residual CO2 2 . 18190 = 152 . grams. 2 . 19069 = 155 . 1 grams. 



Change in residual CO2 = +3 . 1 grams. 



Calculation of carbon dioxide produced during the period. 



,. . , , , , , ,. ^ t J. ■ • f Set No. 1 =4.43 grams. 



Carbon dioxide absorbed from aliquot of outgoing air<j g^^ ^^^ 2 =4.43 grams. 



Volume of aliquot of outgoing air =47.79 cu. ft. 



CO2 of aliquot from ingoing air =0.4779 Xl .48 =0.71 gram. 



CO2 of aliquot produced in chamber =4 . 43 —0 . 71 =3 . 72 grams. 



3 72 



CO2 produced in total outgoing air = — — X 100 = 146 . 5 grams. 



2.54** 



CO2 produced by squad = 146 . 5 +3 . 1 = 149 . 6 grams. 



* After Nov. 11, 1917, it was assumed that each 0.001 per cent change in the residual corresponded 



to 0.8 gram of CO2 and calculations were no longer made. 

 ** 2.54 equals the percentage of the total outgoing air that actually passed through one set of 



the absorption system, i. c, the factor for the 60 mm. disk. 



