cuAP. III. CONFLICTING STATE3IENTS. 57 



At the last reference to Aneroid F (p. 38) its error amounted 

 to — I'OSO of an inch. At the first camp on Chimborazo it was 

 increased to — 1'152 of an inch, and from the above record it will 

 be seen that it still augmented daily. 



Thus, while the mercurial barometer shewed a slight increase 

 in pressure, the whole of the aneroids, on the other hand, indicated 

 pressure diminishing ^ If I had depended upon the latter instru- 

 ments, atmospheric pressure in Ecuador, instead of appearing, as 

 it is, remarkably steady,^ would have seemed liable to large fluc- 

 tuations, and very erroneous suppositions might have been based 

 upon these observations ; or if the altitude of the second camp had 

 been deduced from the means of the six aneroids it would have 

 come out about 1500 feet too high, through adopting a j^ressure 

 for the upper station nine-tenths of an inch lower than the truth. 



The behaviour of these aneroids was so anomalous and jjer- 

 plexing that I felt greatly inclined to read' them no more ; and 

 it was only the apprehension of disaster to the mercurials that 

 induced me to continue to occupy my time in recording obser- 

 vations which appeared perfectly worthless. From subsequent 

 experiments in the workshop ^ it has been found that their be- 

 haviour is neither exceptional nor unintelligible ; but when we 

 were upon Chimborazo it puzzled me exceedingly, and I rushed 

 to the conclusion that I had not been well served, and that my 

 aneroids were emphatically a bad lot. 



Our camp was situated on the southern side of a rather con- 

 spicuous gap in the ridge, and a large rectangular mass of lava 

 against which the tent was placed made a good landmark, which 

 was rendered still more apparent by one of our long poles that 

 was fixed up as a signal. Below us, our ridge spread out con- 

 siderably as it approached the Arenal, and above us it led for a 

 long distance towards the western dome. 



On our right or east, looking towards the summits, there was 



1 See How to use the Aneroid Barometer^ p. 35, § 40. 2 See Appendix B. 

 ^ IJow to use the Aneroid Barometer, pp. 15-34. 



