XXIX 



no desire ; the writer ate only 2 oz. of bread on the summit of the 

 mountain, and that quite in opposition to the will of the stomach. 

 This distaste for food was common to the whole party. During the 

 night, a thermometer inside the tent in which eleven people were 

 closely packed, never sank below 1 C., although the temperature 

 outside was as low as 17 C. The indisposition of the whole party 

 continued, but there was little or no vomiting ; and the prominent 

 symptoms of mountain sickness seemed to be headache, with excessive 

 lassitude and unwillingness to nse the slightest physical, or even 

 mental, exertion. The pulse was rapid but without any fever, except 

 in the case of Tyndall, who continued alarmingly ill during the night. 

 Snow wrapped up in a cloth and applied to his forehead and temples 

 gave him some relief, but his thirst was insatiable ; and as ice would 

 scarcely melt in the warmest part of the tent, it was rarely that any- 

 thing but snow could be obtained for him. Most of the party slept 

 four or five hours, but both, of us remarked that the peculiarity of our 

 position developed <a species of selfishness amongst the men, like that 

 sometimes observed in oases of shipwreck, and which manifested 

 itself in symptoms of insubordination and general discontent. Before 

 leaving the horizontal position in the morning, or 'making any exer- 

 tion, the writer's pulse was found to be still steady at 120, though 

 unaccompanied by any feeling of f everishness. There was nothing 

 unusual in respiration, and no difficulty of breathing. In short, lying 

 there on the floor of the tent, there was nothing in our sensations by 

 which we could have known thai the tent was not pitched at the 

 level of the sea on a frosty morning ; there was no sensation which 

 rendered the great rarefaction of the air perceptible. 



Tyndall, who was now rapidly recovering, superintended the erec- 

 tion and furnishing of the thermometer post, and afterwards experi- 

 mented on the thermal effect of the sun's rays ; whilst the writer 

 occupied himself with the collection of samples of air for analysis, 

 and with experiments in the tent on the rate of combustion of 

 stearin candles, which he had undertaken, at Tyndall's request, in 

 order to test the correctness of the following statement made by Le 

 Conte in Silliman's Journal of Science and Art. " Thus, a variety of 

 well established facts concur in fortifying the conclusions to which 

 we are led by a priori reasoning, namely, that the process of combus- 

 tion is retarded by the diminution of the density of the air, whilst it 

 is accelerated by its condensation." A comparison of the results 

 obtained by burning these six candles for one hour at Chamounix, and 

 for the same time on the summit of the mountain, completely refuted 

 this statement; the amount of stearin consumed under the two 

 widely different barometric pressures, was practically the same. 



Another, and entirely unexpected, phenomenon, however, revealed 

 itself to the writer in the course of these experiments. The candles 



