ULLOA's voyage to south AMERICA. 4^3 



part was covered with ice, hail, or fnow. The day we left this place, while our 

 Indians were loading the mules, and we in the tent ready to fet out on our journey, an 

 earthquake was felt, which reached four leagues round the country. Our tent rocked 

 from fide to fide, in conformity to the undulating motion obferved in the earth ; this 

 fliock was only one of the fmall concuflions frequent in thofe parts. 



XIV. — Signal of Mulmul. 



This iignal, and the three following, occafioned feveral journeys from one to another ; 

 as, for the greater accuracy of the obfervations,-auxiliary triangles were to be formed, 

 in order to verify the diftances refulting from the principal. The difficulty alfo of reci- 

 procally diftinguilhing fome fignals from others, obliged us to change their pofition, till 

 they ftood in proper places ; and confequently laid us under a neceffity of going often 

 from one ftation to another. On the 8th of November, having finiflied all our obfer- 

 vations, the company removed to Riobamba, where I myfelf had been confined ever 

 fince the 20th of Odober,' with a critical difeafe, which at firfl: attacked me at Chichi- 

 choco, and increafing at Mulmul, I was obliged to remain in a cow-houfe on that 

 mountain, from whence I was removed to Riobamba ; and this accident hindered me 

 from being prefent at the fignals XV. XVI. and XVII. which were thofe of Guayama, 

 Limal, and Nabufo. 



XVIII. — Signal of Sifa-pongo. 



At the fignal of Sifa-pongo we continued from the 9th to the end of November ; and 

 here the trigonometrical obfervations were intermitted till Don George Juan and 

 M. Godin returned from Quito, to which city they repaired in order to take fome mea- 

 fures neceffary for the continuation of the work. But, that this interval might not be 

 loft, M. Bouguer propofed to make fome experiments, in order to demonftrate the fyf- 

 tem of attradion. The place he made choice of for thefe experiments was the moun- 

 tain of Chimborazo. In this ftation, and the following, of the fandy defert of the fame 

 mountain, we fuffered more than on any other. 



XIX. — Signal of Lalangufo. 



On the defert of Lalangufo, our obfervations were continued from the 24th to the 

 31ft of January 1739. 



XX. — Signal on the Defert of Chufay. 



The ftation on the defert of Chufay was one of the moft tedbus in the whole feries 

 of triangles, being unavoidably detained on this difagreeable mountain from the 3d of 

 February to the 24th of March. This delay was occafioned by the difficulty of pitching 

 on proper places for ereding the fucceeding fignals, that they might ftand in full view, 

 be eafily diftinguiftied one from another, and form regular triangles. This was indeed 

 a difficult talk, the lofty fummits of the mountains of the Cordillera of Azuay, where 

 they were to be placed, intercepting each other from our fight. The tedioufnefs of this 

 ftation was increafed by the rigour of the weather, the ftrength of the winds, and its 

 great diftance from any place where we could procure convenient fhelter and re- 

 frefliments. 



VOL. XIV. 3 K XXL 



