•426 



Dr. W. Marcet, 



[Feb. 10, 



not conducive to warmth. Food, good, abundant and substantial, 

 would have offered the best means to counteract the cold, but our 

 supply was scanty, as we had been disappointed in the expectation of 

 obtaining provisions at the half way house, the Pavilion du Mont 

 Frety, and even had food been abundant, want of appetite and inability 

 to digest with both of us would have prevented our taking advantage 

 of it. As it was, we lived mostly on soup made with extract of beef 

 and preserved julienne, bread and cheese, coffee and tea with condensed 

 milk, some chocolate, and a small quantity of meat from tins. The 

 nights we felt bitterly cold and uncomfortable, and we could get but 

 very little sleep. No wonder that under such depressing circumstances 

 we were unable to make in our bodies the amount of heat required to 

 meet the occasion ; the result, in fact, was, as I have already stated, a 

 diminished combustion in both of us.* 



I now wish to offer a few remarks on the difference in the weight of 

 carbonic acid expired by myself and M. David respectively at the 

 several stations. M. David is 25 years of age, weighs 11 stone 7 pounds 

 (73 kilos.), and measures round the chest 37*6 inches, while I am 52 

 years of age, weigh nearly 10 stone 8 pounds, and measure 34'5 inches 

 round the chest. M. David expired more carbonic acid than I did, 

 though not in proportion with the excess of weight of his body. If the 

 figures showing the carbonic acid expired by each of us be reduced to 

 the same temperature for each station, the fixity of the excess of 

 carbonic acid expired by M. David, not only at the different stations 

 respectively, but also throughout the whole of the present inquiry, 

 becomes quite obvious. 



At Yvoire my first series of experiments yield O504 C0 2 at 69 0- 9 ; 

 and M. David's only series, 0*776 C0. 3 at 61°*6, the reduction 

 to the same temperature giving an excess of 26*3 per cent, for 

 M. David. My second series of experiments at Yvoire, compared 

 with M. David's single set of experiments at that station, shows a 

 difference of atmospheric temperature from 60° "3 to 61° "6 ; after apply- 

 ing the reduction, the excess of carbonic acid expired by this gentle- 

 man will be found to amount to 27*9 per cent., or within narrow limits 

 of the percentage first obtained. 



At Courmayeur,.for the first series of experiments, after applying 

 the correction for temperature, the excess of carbonic acid expired by 

 M. David was found to be 27*4 per cent. The second series at Cour- 

 mayeur showed an excess of carbonic acid expired (duly corrected) 

 by M. David amounting to 27*9 per cent., or very nearly the same as in 



* My experimental baggage consisted of a trunk weighing 40 kilos. (88 lbs.), a 

 basket weighing 35 kilos. (77 lbs.), and the wooden shed ; three porters from Cour- 

 mayeur carried up the whole of this baggage from the Pavilion du Mont Frety ; I 

 engaged a fourth for taking the baggage down. The work of these porters was a 

 remarkable feat of bodily strength and mountaineering. 



