1821.] Col. Beaufoy on a new Wind Guage. 433 



brass plate, fixed upon the upper part of the tripod stand ; and 

 P another plate connected with the block, M, by a brass fork, 

 Q, and centre pin, R, as may be distinctly seen in fig. 7, forming 

 a turning joint capable of a slight motion to adjust the apparatus 

 into an horizontal position, which is determined by the spirit 

 level, L, fixed upon the block, M. The motion upon the centre 

 pin, R, is regulated by two milled head screws, T T, passing 

 through a strong brass cock or angle piece, V ; fixed by three 

 screws to one side of the fork, Q, the ends of the screws, T, 

 bearing upon the top of the block, as may be seen in the section, 

 fig. 7. ni m, represent two thumb screws, which enter into 

 holes in the plate O, and pass through oblong grooves, n n, in the 

 plate P (see fig. 3), to allow of turning the apparatus round a 

 small quantity to adjust it into the direction of the wind. W, 

 shows the dial plate, which is divided into 100 equal parts, and 

 numbered at every tenth division. The dial plate is placed con- 

 centric with the fusee axis, which has a needle, w, fixed upon 

 the end of it, to point out the portions of a turn of the fusee ; 

 and the small circle of five divisions upon the dial is furnished 

 with a needle, x, moved by a wheel and pinion (situated behind 

 the dial, as will appear in figures 3 and 6), of such number of 

 teeth as to cause the small needle, x, to advance only one divi- 

 sion during an entire revolution of the needle, w. The small 

 needle will indicate the number of turns which the silk cord has 

 made upon the fusee, F. X represents the stick which carries 

 the wind flag upon the top of it. 



The apparatus is furnished with weights of various sizes, to be 

 used in strong or light winds ; they are adapted to pack up in a 

 case along with the apparatus in order to be removed from one 

 place to another in a convenient manner. The screen, A, may 

 be taken off, and carried separate by withdrawing the screw pin, 

 p ; Z, fig. 2, shows a small brass hook, which is adapted to enter 

 into a hole formed in the bar, B, to prevent its running out and 

 breaking the chain in setting up the apparatus for use. 



To find the value of each division on the dial plate, or power, 

 requisite to move the hand, w, and raise the weight, H ; one end 

 of a silken line was fastened in the hole, B, fig. 4. To the other 

 extremity was hung a light tin cup, the intermediate part of the 

 cord passing over a well made pulley, suspended from the ceil- 

 ing of a room ; and in this cup were placed a sufficient quantity 

 of small leaden shot, to move the index one division. The line 

 was afterwards detached, and weighed with the cup and shot; 

 the result written down in a table, and afterwards reduced to 

 pounds and decimal parts of pounds avoirdupoise. But as the 

 cylinder and fusee were accurately turned, and the spiral truly 

 cut, it was found not necessary to examine each division, every 

 tenth one being sufficient, with the intermediate blanks filled up 

 by taking proportional parts of the different weights. 



New Series, vol. ii. 2 r 



