the 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



NOVEMBER 1869. 



XXXIX. Observations on the Temperature of the Human Body at 

 various Altitudes, in connexion with the act of Ascending. By 

 William Marcet, M.D., F.R.S., Assistant Physician to the 

 Hospital for Consumption and Diseases of the Chest, Br ompton*. 



DURING an excursion over the Mont-Blanc range I had an 

 opportunity this summer of ascertaining the temperature 

 of my body under various circumstances connected with the act 

 of ascending. The number of observations is, I must admit, 

 much too small; still their individual results, when compared 

 with each other, agree closely enough to allow of certain conclu- 

 sions to be derived from them. 



I had with me a thermometer carefully made by Casella, and 

 divided in fifths of degrees Centigrade, allowing of a tenth of a 

 degree to be read off. The instrument could be accurately ob- 

 served while its bulb was under my tongue, by means of a 

 small mirror which, on being placed near the stem of the 

 thermometer at a certain angle, reflected its image into my eyes, 

 so that I could see the mercury rising or falling as plainly as 

 if I was looking at it directly f. It is useless to add that in 



* Communicated by the Author, haying been read to the " Societe de 

 Physique et d'Histoire Naturelle of Geneva" on the 3rd of September, 1869. 



t On every occasion, I observed the height of the thermometer several 

 times, and made sure of its being constant before noting the temperature, 

 thus avoiding the fallacy which may easily arise from too short an exposure, 

 as shown by Dr. Ch. Baeumler (Brit. Med. Journ. August 1869). Two ob- 

 servations made in London in the sitting posture, at 11 a.m. (breakfast 

 at 9), with a thermometer constructed for me since my return by Casella, 



Phil Mag. S. 4. Vol. 38. No. 256. Nov.. 1869. Z 



