1871.] Dr. A. Rattray on the Effects of Change of Climate. 295 



proximate quantitative values of the shearing-forces and bending-moments 

 obtained for the three ships, ' Minotaur,' ' Bellerophon/ and 'Victoria and 

 Albert':— 



lu still water 



On a wave-crest 



In a wave-hollow 



Supported at the extremities 

 Supported at the middle 



Shearing- 

 force. 



Displac 

 merit. 



Bending- 

 raomcnt. 



Displace, 

 x length. 



_1_ 



8 8 



1 



a 8' 



BelleropLon 



' Victoria and Albert/ 



Shearing 

 force. 



Displace- 

 ment. 



1 



Bending- 1 Shearing- 

 moment. I force. 



Displace, 

 x length. 



1 



1 7 e 



_i_ 



■1 o 



Displace- 

 ment. 



February 16, 1871. 

 General Sir EDWARD SABINE, K.C.B., President, in the Chair. 



The following communications were read : — 

 I. et On some of the more important Physiological Changes induced 

 in the Human Economy by change of Climate, as from Tempe- 

 rate to Tropical, and the reverse" (concluded)*. By Alexander 

 Rattray, M.D. (Edinb.), Surgeon R.N., H.M.S. f Bristol.' 

 Communicated by Mr. Busk. Received January 6, 1871. 



IV. The influence of Tropical Climates on the Kidneys and Skin. 

 None of the organs of the body are more visibly affected by great changes 

 of climate than these, and their secretions, the urine and perspiration. As 

 with the lungs f and other internal viscera, the congestion of the kidneys 

 lessens, while that of the skin increases, when the blood is attracted to the 

 surface by heat. The reverse happens when it is driven inward by cold. 

 This involves their special and vicarious, waste-product and water-excreting 

 functions alike. In the tropics the skin doubtless excretes much of the 

 water thrown off by the kidneys and lungs in colder regions, as well as the 

 nitrogen and carbon of the former, and carbonic acid of the latter. The 

 elimination of surplus water, one of the most important uses of all of the 

 four great depurating organs, is largely effected by these two. Their in- 

 timate relation in this office in cold latitudes is already known. "We shall 

 here attempt to show what it is in the tropics. 



* Continued from Proceedings of the Koyal Society, June 16, 1870, vol. xviii. p. 529. 

 t Ibid. p. 523. 



