24 EXPERIMENTS ON 



11. 



Dcscriptioti of a "very sensible Hygrometer y 



BY LIEUTENANT HENRY KATER, 

 H. M. I2th Regiment. 



XN the Mysoor and Carnatic is found a species of 

 grass, which the nativ^es call, in the Canarese lan- 

 guage, Oobeena hooloo, in the Maratta, Guvataa see 

 cooslee, and, in Tamul, Yerudoovaal pilloo*. It is met 

 with in the greatest abundance, about the month of 

 January, on the hills; but maybe procured in al- 

 most every part of the country, and is very gene- 

 rally known. 



Accident led me to remark, that the bearded seed 

 of this grass possessed an extreme sensibility of mois- 

 ture; and being then in want of an hygrometer, I 

 constructed one of this material, which, on trial, far 

 exceeded my expectations. 



I caused a box to be made of brass, four inches in 

 diameter, and an inch and a half in depth. Within 

 the box, about a quarter of an inch from the top, was a 

 flat ring, three-tenths of an inch in breadth, and di- 

 vided into a certain number of equal parts. A hole 

 was made, through the centre of the bottom of the 

 box; and a circular plate of brass, about an inch 

 in diameter, was rivetted to the bottom. On the 

 outside, a notch was made in the rivet, similar to that 

 in the head of a common wood screw; so that the 

 circular plate, within the box, could be turned round, 

 at pleasure, by means of a turn-screw, applied to the 

 notch on the outside. 



* It is the Andropogon Contortum of LiNN^us, and may be ea- 

 sily distinguished from all others, by the seeds attachiiig themselves 

 to the clothes of those who walk where it grows. 



