DESCRIPTION OP AN IMPROVED HYGROMETER. SQ/ 



If two of these Hygrometers, in which the extremes 

 of dryness and moisture are well determined, be com- 

 pared together, they will seldom differ ten divisions 

 from each other, which is as near a coincidence as can 

 be expected. 



The ooheena hooloo or Androfogon Contorhis is found 

 in every part of the country, in the month of January, 

 when it should be gathered, and thoroughly dried in- 

 the sun, before it is used. 



This grass appears to be far superior to any other 

 hygroscopic substance, hitherto discovered. In the 

 Encyclopaedia Britannica, the scale of Saussure's 

 Hygrometer is said to consist of 400 degrees, or ra- 

 ther more than one revolution of the index ; the Hy* 

 grometer here described makes eleven or tivelve revo- 

 lutions ; it possesses also the advantage of being per- 

 fectly portable, cannot easily be deranged, and maybe 

 much reduced in size, if thought necessary, without 

 affecting the extent of the scale. 



