190 



REPORTS ON INVESTIGATIONS AND PROJECTS. 



Using the electrical method of control, it was possible to determine the 

 hydrothermal equivalent of the respiration calorimeter by introducing a cer- 

 tain amount of heat into the chamber and allowing the temperature of the 

 apparatus to rise slowly. Obviously in this operation the heat brought away 

 by the cooling water-current was less than that introduced by the amount 

 absorbed by the chamber as its temperature rose. This amount gave accu- 

 rate data for computing the hydrothermal equivalent of the apparatus. The 

 reverse operation was then carried out, namely, the rate of withdrawal of the 

 heat by the water-current was arbitrarily adjusted so as to cool the whole 

 chamber somewhat and the excess of the heat withdrawn over and above 

 that developed by the electric current gave means for computing the hydro- 

 thermal equivalent of the chamber. With the bed calorimeter this was found 

 to be 19.5 kg. of water, and with the chair calorimeter 21 kg. of water. 



The most rigid control, however, is obtained in experiments in which a 

 definite amount of alcohol is burned inside the chamber and all four of the 

 factors are measured. The results of an experiment of five consecutive 

 i-hour periods is given in the table herewith : 



Alcohol Check Experiment. Chair Calorimeter, November 18, 1909. (i-hour Periods.) 



To obtain duplicate results in the determination of a single chemical ele- 

 ment or radicle by analysis frequently requires a number of determinations, 

 and when two factors are simultaneously determined, as carbon and hydrogen 

 in elementary organic analysis, still greater difficulty is experienced. It can, 

 therefore, easily be seen that the simultaneous determination of four factors 

 presents a problem that is rarely met with in either physical or chemical oper- 

 ations and heretofore never in physiological chemical operations. Indeed, 

 the apparatus has proved as accurate as any chemical process ordinarily used 

 in a laboratory, and it can accordingly be characterized, both calorimetrically 

 and chemically, as an instrument of precision. 



(3) The composition of some Bengali food materials. Hope Sherman and H. L. Hig- 

 gins. Jour. Amer. Chem. Soc, 32, rv, p. 558. 1910. 



In this paper are reported analyses of a number of Bengali food materials 

 sent to the Nutrition Laboratory by Captain McCay, Professor of Physiology 

 in the Calcutta Medical College. The materials included wheat, corn, pulse, 

 and rice, all of which are commonly used in the diet of the Bengalis. The 

 analyses were compared with the analyses of American food materials and 

 it was found that the wheat flour as prepared in India had a considerably 

 higher absolute fat content than ordinary American flour. Twenty-three 

 samples were analyzed and the heats of combustion determined. 



