XVI 



APPENDIX. 



Register of the Hygrometer for Eight Years, registered at the same Hours as the 

 Thermometrical Observations in the preceding Tables. 



From long-continued attention to my Hygrometer (Capt. Kater's), I placed much dependence 

 on its sensibility. On some occasions I have noticed its changes were occasioned by passing 

 clouds, at times of the day when the index previously had indicated much dryness ; when the 

 cloud had passed over, the index soon regained the point from which it had moved half an 

 hour before. The high numbers indicated in the columns of the maximum, occurred in the 

 early hours of the morning, and were greater or less according to the continuance and density 

 of the fogs. 



The instrument always stood at a distance from any door or window, but both doors and 

 windows being open, it received all the influence of a moist or a dry atmosphere. The low 

 numbers indicate a very dry state of the atmosphere ; at 2-60 the leather binding and thin paste- 

 board covering of books began to curl, and at from 2-00 to 1-60 pens split as soon as laid aside, 

 ink uncovered was rapidly absorbed, and water standing in a porous earthen vessel cooled by eva- 

 poration to ten degrees below the thermometer. 



The scale or range of this instrument was to 11-94, the point of complete saturation. 



The blanks in this table were occasioned by the hygrometer being under repair. Its action was 

 impaired by dust, but was restored by cleaning. 



