IX. 



Description of an improved Hyghomete^i^* 



ET LIEUTENANT HENKY KATER, 

 0/His Majesty's \2ih Regme?it. 



OiNCE I had the honor of lajnng before the Asiatick 

 Society "a description of a very sensible Hygrometer," 

 I have attended much to the improvement of the in- 

 strument, and am induced to think that some further 

 account of it may not be deemed wholly unacceptable. 



The principal objection to the Hygrometer described 

 in my former paper, arose from the necessity of short- 

 enmg the beard of the ooheena hooloo ^, in order to re- 

 duce the scale, to a convenient length ; this was to be 

 obviated, only by giving the instrument a circular form, 

 and inventing some mode of ascertaining without diffi- 

 culty tile number of revolutions made by the index. 



ABCD (fig. 1) is a frame, made of small square bars 



of brass or si'ver ; this plate is soldered to a square plate 



BE, the edges of which are turned up, as represented 



by the dotted lines, to secure the i?idex from injury ; 



on the face of the plate is engraved a circle (see fio-, 4) 



which is divided into one hundred equal parts. Three 



holes, a, b, c, are made through the frame and plate in 



the same direction ; the holes a & b, are of a conical 



form as represented by the dotted lines, and are highly 



polished to lessen friction ; the hole at c receives a screw, 



one end of which is tapered, and has a notch cut in it 



with a fine saw, which may be closed by means of the 



sliding ring d. 



The axis e f, is made of silver wire, very smooth and 

 straight, and of the size of a large knitting needle ; on 

 the axis, a screw is formed, by twisting a smaller silver 



Andro^ogon Coniorius. 



