[ 179 ] 



XXXII. Meteorological Observations during a Residence in 

 Colombia between the Years 1820 and !830. By Colonel 

 Richard Wright, Governor of the Province of Loxa, 

 Co7ifidential Agent of the Republic of the Equator ^ S^c. S^c. 



[Continued from p. 104.] 



On the Method of Measuring Heights by Boiling Water. 



IT will be observed in the following Journal, that the indi- 

 cation o^ heights is, in most cases, joined with that of boil- 

 ing water. The former is in fact a deduction from the latter ; 

 I had but a confused idea of this method, till, upon my ar- 

 rival at Quito, I met with a pamphlet of the late D. Francisco 

 Jose Calclas (one of the most eminent victims sacrificed by 

 the barbarity of Murillo on taking possession of Bogota in 

 1816) published in 1819 at Bourdeaux, in which he details the 

 steps by which he arrived at a knowledge of this principle, 

 and the experiments by which he confirmed it. In the year 

 1801, during a scientific excursion in the neighbourhood of 

 Popayan, he happened to break his thermometer ; and in at- 

 tempting to mend it he was led to observe the variability of 

 the extremity of the scale corresponding to the heat of boiling 

 water. His reflections on this subject led him, after various 

 experiments, to the following conclusions : " The heat of boil- 

 ing water is in proportion to the atmospherical pressure : the 

 atmospherical pressure is in proportion to the height above 

 the level of the sea; the atmospherical pressure follows the 

 same law as the risings of the barometer, or, properly speaking, 

 the barometer shows nothing more than the atmospherical 

 pressure. Boiling water therefore shows it in the same man- 

 ner as the barometer. It can consequently show the eleva- 

 tion of places in the same manner, and as exactly as this in- 

 strument." Ensayo de una memoria sobre un mievo metodo 

 de medir las montanas, etc. p. 10. His first experiment in 

 Popayan gave b. w. 75°*7 of Reaumur, the height of the ba- 

 rometer being 22 in. 111. To find then the variation cor- 

 responding to one inch of the barometer : 



28in- —22'"- ll'- = 5°-l or 61 lines. 



80° — 75°-7 = 4'°-3. Then 



611- : 't^-S :: 12'-: ^'°'^^^^ = 0°-8. 

 61 



Then reversing the process 



4°-3x 12 

 0°-8 



N2 



0°-8 : 121- : : 't°-3 r^^-^ = Q^'5 = 5* 



