NUTRITION LABORATORY. 191 



(4) An adiabatic calorimeter for use with the calorimetric bomb. Francis G. Benedict 



and Harold L. Higgins. Jour. Amer. Chem. Soc, 32, iv, p. 461. 1910. 



In all investigations in calorimetry, the great and serious obstacle is the 

 cooling correction or the interchange of heat between the calorimeter and the 

 surrounding medium. With the new type of calorimeter the temperature of 

 the surrounding medium is arbitrarily controlled so as to always equal that 

 of the calorimeter itself, thus doing away with any interchange of heat. In 

 the investigations described in this paper the Kroker modification of a Ber- 

 thelot bomb calorimeter was used, although any other bomb can be em- 

 ployed. The calorimeter vessel containing water in which the bomb was 

 immersed is placed inside of a nickel-plated brass can, allowing a certain air- 

 space between the calorimeter can and its outer nickel vessel. This outer 

 vessel is in turn surrounded by a water-jacket whose temperature can be arbi- 

 trarily raised by means of an electric heater. A turbine stirrer keeps the 

 water in agitation and a delicate thermometer enables the reading of the 

 temperature. Passing a current of electricity through the electric heater in 

 the outer jacket maintains the temperature of the water at any desired point; 

 and throughout the whole calorimetric operation the temperature difference 

 between the inside and outside is negligible. The apparatus has been most 

 rigidly tested and has given the most satisfactory results. It promises to be 

 an important addition to calorimetric investigation and supplements the 

 admirable calorimeter devised by Richards, Henderson, and Frevert for spe- 

 cial scientific experiments. 



(5) Elementary analysis by means of a calorimetric bomb. Harold L. Higgins and 



Alice Johnson. Jour. Amer. Chem. Soc, 32, rv, p. 547. 1910. 



In nutrition investigations innumerable analyses of organic materials are 

 involved in which the carbon and hydrogen content must be known. Usually 

 on the same sample there must also be a determination of the heat of com- 

 bustion. This paper describes a method of carrying out in practically one 

 operation the determination of the heat of combustion of a material and of 

 the carbon and hydrogen. The substance is burned in a calorimetric bomb 

 and the heat eliminated is measured by the rise in temperature of the water 

 in which the bomb is immersed. The organic material after combustion has 

 been converted into carbon dioxide and water. The gases in this bomb are 

 then allowed to escape and samples are taken and analyzed on a Haldane 

 gas-analysis apparatus. By weighing the bomb before a combustion and after 

 the gas has been allowed to escape, it is possible to compute with great accu- 

 racy the carbon and hydrogen content. The method has been checked by 

 determining the carbon and hydrogen in pure substances, such as sugar, 

 urea, uric acid, and benzoic acid. The results have been most gratifying, 

 and the method has proved of great service in the routine analyses connected 

 with metabolism experiments. 



(6) Respiration calorimeters for studying the respiratory exchange and energy transfor- 



mations of man. Francis G. Benedict and Thorne M. Carpenter. Publication 

 No. 123, Carnegie Institution of Washington. 1910. 



In the two calorimeters described, one of them for bed-ridden patients, 

 the heat eliminated by man is measured by a current of cold water passing 

 through a heat-absorbing system inside the chamber, the mass of water and 

 the temperature-rise being known. Direct measurement of the water vapor- 

 ized gives the latent heat of water-vapor. By means of a system of thermal 



