144 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



Fig. 623. 



the cylinder. The 

 water stands at the 

 same height in the 

 cylinder and glass 

 tube, and being visi- 

 ble in the latter, the 

 height is read imme- 

 diately on the scale ; 

 and the cylinder and 

 tube being construct- 

 ed so that the sum 

 of the areas of their 

 sections is a given 

 part, for instance a 

 tenth, of the area of 

 the funnel at its ori- 

 fice, each inch of 

 water in the tube 

 is equivalent to the 

 tenth of an inch of 

 water entering . the 

 mouth of the funnel. 

 A stop-cock is add- 

 ed, by which the 

 water is drawn off 

 when the observa- 



It is usually made of tin, and well japanned. 



Price, $7.50. 



The same, with float within the cylinder and scale in the 

 form of a rod, indicating the quantity by the rise of the rod 

 and float. Price, $6.00. 





tion iv made. 



Lind's Wind Gauge. (Fig. 624, as above.) An instru- 

 ment serving to determine the velocity and force of the wind. 

 An apparatus which is simple and easy of construction, and 

 which seems to be well adapted for measuring the force of 

 the wind with a sufficient degree of accuracy, consists of two 

 glass tubes, A B, c D, five or six inches in length, and about 

 four-tenths of an inch in bore ; which are connected together 

 like a siphon, by a small bent glass tube, a b, the bore of 

 which is one-tenth of an inch in diameter. On the upper 

 end of the leg, A B, there is a tube of latten brass, which is 



