232 Dr. W. Marcet, 



IV. " Effects of prolonged Heating on the Magnetic Properties of 

 Iron." By S. R. ROGET. Communicated by Professor EWING, 

 F.R.S. 



V. " On the Connection of Algebraic Functions with Automorphic 

 Functions." By E. T. WHITTAKEB. Communicated by Pro- 

 fessor FORSYTH, F.R.S. 



The Society adjourned over Ascension Day to Thursday, May 26. 



"A Calorimeter for the Human Body." By WlLLIAM MARCET, 

 M.D., F.R.S. Received March 10, Read April 28, 1898. 



(From the Physiological Laboratory, University College, London.) 



At the meeting of the Physiological Society held at University 

 College in March, 1897, I exhibited and described a calorimeter con- 

 structed for the purpose of determining the heat given out by man. 

 'Several members of the Society, in succession, allowed themselves to 

 foe shut up in the chamber where they experienced no discomfort 

 whatever. The instrument was also described the same year to the 

 ;Societe de Physique et d'Histoire Naturelle of Geneva, but no full 

 account of it has been published so far. 



The first calorimeter for the investigation of animal heat was made 

 "by Lavoisier and Laplace,* who enclosed an animal in a chamber 

 rsurrounded with ice and determined the heat evolved by measuring 

 -the amount of ice melted. Crawford, in 1788, placed the air chamber 

 inside a water-jacket, and determined the heat emitted by means of 

 -the increased temperature of the water. An objection to this 

 iype of calorimeter is the very small rise in the water temperature, 

 and the difficulty of obtaining an uniform temperature in such a large 

 volume of water. J. Rosenthal,f in 1878, introduced a calorimeter 

 in which the heat given out from a small animal was absorbed by a 

 fluid with a low boiling point, such as ordinary ether, the amount of 

 heat was calculated from the volume of the fluid evaporated and its 

 known latent heat of vaporization. 



RosenthaljJ at a later date, constructed a calorimeter, which con- 

 sisted of three concentric chambers of sheet copper, and was made 

 in duplicate; the two instruments were connected by means of a 

 U-shaped manometer. The heat given out by an animal, such as a 

 -dog, enclosed in the innermost chamber of one of the instruments, 



* * Memoires de 1'Acad. des Sciences,' 1780. 

 f ' Archiv f. Anat. u. Physiol.' (Physiol. Abthg.), 1878, p. 349. 

 j C. Kosenthal, 'Arch. f. Anat. u. Physiol.' (Physiol. Abthg.), 1888. p. 1; J. 

 JRosenthal, ibid., 1889, pp. 1, 23, 39. 



