CHAP. III. LIFE AT LOW PRESSURES. 53 



get air ; and my two assistants^ spontaneously and without any 

 questioning or prompting on my part, attributed the condition in 

 which we found ourselves to the ' rarity of the air ' at our second 

 camp. There is evidence of my own inability to perform my 

 regular work in the blanks in my journals at this date, and 

 further evidence of the reality of the attack in the fact that we 

 could not smoke. Two out of the three were habitual consumers 

 of tobacco, and had become slaves to this vice to such an extent 

 that they smoked conscientiously upon every opportunity. When 

 such persons put aside their beloved pipes there is certainly some- 

 thing Avrong. All three found smoking too laborious, and ceased 

 their efforts in a sort of despair. But it should not be understood, 

 from anything which may have been said, that I discussed the 

 subject with the Carrels, for I considered it best to leave them in 

 ignorance of the fact that they were the subjects of a scientific 

 enquiry. 



There was a perceptible improvement in their condition on 

 the night of Dec. 28, though little in my own. On the 29th they 

 were eager to be off exploring, and I sent them away at 7.50 a.m., 

 instructing them to continue the ascent of the south-west ridge ; 

 to look out for a higher camping-place ; and not to endeavour to 

 reach a great elevation. Owing to my lifeless condition, I should 

 only have hampered their movements by accompanying them, 

 and while they were away I turned my attention again to the 

 barometers. 



The two mercurial barometers arrived safely at the second 

 camp. One of them (No. 550) was stowed away in a cleft in the 

 rocks, and the other (No. 558) was alone used on Chimborazo. 

 It may be of some service to travellers to mention the precautions 

 which were taken in regard to these instruments. 



There are two principal reasons why so many mercurial baro- 

 meters are broken in the field. 1. Because they are insufficiently 

 protected when in transit ; and 2. because a bad method of sus- 

 pension is employed when they are being observed. Mountain 



