258 Professor Kaemtz on the more important 



proved by observations which I continued on the Faulhorn for 

 twelve weeks, during the two years already mentioned. 



From the relations which have now been discussed, a ques- 

 tion arises, a reply to which would be of the greatest consequence 

 for a multitude of problems that have hitherto not been dis- 

 tinctly cleared up : it is the following, — Are the upper strata 

 of the air, on an average, moister or dryer than the lower ? I 

 need hardly remark that I do not here speak of the absolute 

 humidity ; for, as the height of the barometer diminishes with 

 the increased elevation, so must also the amount of vapour be- 

 come smaller, — a view which is confirmed by experience ; the 

 whole investigation turns on the greater or smaller distance of the 

 air from saturation. Saussure and De Luc, who were the first to 

 carry hygrometers to the higher regions of the atmosphere, ex- 

 pressed decidedly the opinion, that the upper strata of air are 

 much dryer than the lower. In judging of this assertion, we 

 must not overlook the circumstance, that the observations of 

 these philosophers were made during excursions in the moun- 

 tains, for which every one selects the most serene and the dry- 

 est weather. The only series of comprehensive measurements 

 was made by Saussure during a residence of several weeks on 

 the Colde Geant, but unfortunately these observations were ren- 

 dered less important, because he selected for comparison, only 

 days when he was not surrounded by clouds, which, by their 

 moisture, would probably have afibrded compensation for the 

 dryness of the serene days. Afterwards, Humboldt, in South 

 America, arrived at the same result ; and as in this case we have 

 to do with a several years'* residence among the Andes, we must 

 consider the conclusion as more certain ; but here also we must 

 not forget, that the lower places lie near the coast, and the higher 

 in the interior of the Continent; and, since with us the air is much 

 dryer below than it is there, we may hence, from this cause, ac- 

 count for the greater dryness in the higher strata of the air. 



When we consider that the summits of the mountains are of- 

 ten surrounded by clouds for weeks together, while the lower 

 strata of air are far removed from saturation, and since on plains, 

 during great dryness of the air, we see innumerable clouds pass- 

 ing over the sky, the opinion does not seem very probable that 

 the upper regions of the atmosphere are dryer than the lower. 

 Up to the present time, comprehensive observations, continued 



