VERY SENSIBLE HYGROMETER, Cgyf 



ber of combinations in each term would have been equal to 



the number in the p ■{- 1 left-hand terms of the preceding 

 line. And exactly the same law is observed when we mul- 

 tiply this last product by (1 -f- d + d* — d?)> that is to say> 

 each term of the new product is equal to the number of 

 combinations in the q -f- I left hand terms of the line which 

 precedes it ; and so on, for any number of multiplications 

 whatever. Whence the truth of the rule is manifest* 



We may farther remark, that, if the greatest number of 

 things to be taken at a time exceeds half the number *>f 

 things given, still, we need not pursue the operation for 

 more than half the given number, as will be evident from 

 a closer inspection of the above formulae. For it must be 

 readily observed, that, were we to carry the operation of 

 each multiplication to its whole extent, the terms on each 

 product would increase, from the first to the middle terms, 

 and then decrease again in the same manner to the other 

 extremity of the line. 



Yours, &c. 



PETER BARLOW. 



Royal Military Academy, Woolwich, 

 May 31 Jf, 1809. 



IX. 



Description of a very sensible Hygrometer. By Lieutenant 

 Henry Kater, of his Majesty's l c 2th Regiment*, 



N the Mysoor and Carnaiic is found a species of grass, An India* 

 which the natives call, in the Canarese language, oobeena « ra:JS 

 hooloo, in the Maratta, guvataa see cooslee, and, in Tamul, 

 yerudoovaal pilloo'f. It is met with in the greatest abun- 

 dance, about the month of January, on the hills; but may 

 be procured in almost every part of the country, and is very 

 generally known. 



* Abridged from the Asiatic Researches, vol. IX, p. 24. 



•f It is the andropogon contortum of Linnxus, and may be easily dis» 

 tinguished from all others, b/ the seed; attaching themselves to the 

 clothes *f those who walk where it grows. 



Accident 



