ATMOSPHEROLOGY. S8l 



that was observed, amounting to 2T, occurred on 

 the 5th of May, when the temperature was 27°. 

 But the average state of the hygrometer was not, I 

 believe, more than 5° or 6° of dryness in May, per- 

 haps 7° or 8° in the beginning of June and end of 

 July ; and when the foggy season prevailed, from 

 the 25th June to the 14th July, the greatest dry- 

 ness was only 5°, and the average probably not 

 above 2 or 3 degrees. But though the air in the 

 polar regions be so generally damp, yet it is proba- 

 ble, that there is no habitable situation in the known 

 world, in which such a degree of actual dryness pre- 

 vails, as in a house, or in the cabin of a ship, well 

 heated, when the external air is intensely cold. In 

 calm weather, I have frequently had my cabin heat- 

 ed up to 60°, when the external air was as cold as 

 10* or 15°. In such cases, the evaporation from 

 the bulb of a common thermometer, coated with 

 filtering paper wetted with water, has occasioned a 

 reduction of temperature in the instrument, of 10° to 

 15°; and Leslie's hygrometer has marked an extent of 

 dryness exceeding 150 degrees. When the external 

 air was at the temperature of 26°, and the cabin 50°, 

 the hygrometer marked 85° ; and when the tempera- 

 ture in the open air was 30°, and in the cabin 64°, 

 the hygrometer indicated 7° of dryness in the for- 

 mer, and 102° + in the latter. Now, Professor Les- 

 lie observes, that when the hygrometer indicates 50 

 or 60 degrees, we account it very dry, and from 70 



