6 



ceptions. From these united causes, the na- 

 tives who inhabit the Missions are kept in a 

 state remote from all improvement ; and which 

 we should call stationary, if societies did not 

 follow the course of the human mind, and must 

 therefore be said to retrograde, whenever they 

 cease to go forward. 



On the 4th of September, at five in the morn- 

 ing, we began our journey to the Missions of the 

 Chayma Indians, and the group of lofty mountains 

 which traverse New Andalusia. We had been 

 advised, on account of the extreme difficulties 

 of the road, to reduce our baggage to a small 

 bulk. Two beasts of burden were indeed suffi- 

 cient to carry our provision, our instruments, 

 and the paper necessary to dry our plants. One 

 chest contained a sextant, a dipping-needle, an 

 apparatus to determine the magnetic variation, 

 thermometers, and Saussure's hygrometer. We 

 always selected these instruments in excursions 

 of short duration. The barometer requires 

 more attention even than the time-keeper; and 

 it may be well to add, that this instrument 

 embarrasses travellers more than any other. 

 We confided it during five years to a guide, 

 who followed us on foot ; and this precaution, 

 which was expensive, did not always secure it 

 from accidents. Having determined with pre- 

 cision the period of the atmospheric tides, that is, 

 the hours at which the mercury rises and falls 



