L. CASELLA'S CATALOGUE 



80. Casella's Embossing Self-recording Anemometer^ for registering the velocity 



and direction of the 'wind and the time of its various changes. 



The general principle of this 

 instrument is that of Dr. 

 Robinson, of Armagh, in 

 which four hemispherical cups 

 revolve with the pressure of 

 the wind, and give action to 

 most of the other parts. The 

 registering parts of the instru- 

 ment, however, as well as the 

 vane are entirely neiv, and 

 the result of the joint efforts 

 of myself together with those 

 of Mr. Beckley, the ingenious 

 engineer of the Royal Kew 

 Observatory. The Force-and- 

 Die principle of embossing is 

 the means of registration here- 

 in adopted. The paper em- 

 ployed is a narrow strip, 

 wrapped round a small attached 

 roller, from which it is drawn, 

 and embossed on one edge by 

 the action of the rollers, as 

 shown in the sketch. The 

 rollers are divided to represent 

 miles ; they are figured at every 

 ten, and one revolution shows 

 the wind to have travelled fifty 

 miles. The clock (a] raises the 

 small hammer (b) which falls 

 once in every hour, impressing 

 the other edge of the paper with 

 a small arrow ^f^* 



whose movements are identical 

 with the larger one at the top, 

 and thus shows the exact direc- 

 tion of the wind at the time, as 

 well as its rate of speed during 

 each preceding hour. The paper 

 is of sufficient length to last 

 from four to six weeks with- 

 out being changed, and the 

 clock may be wound up daily 

 or weekly, as may be desired. 

 The projection (6-) contains 

 metal balls, which firmly 



80 - support the top, and aid 



in giving freedom of action. The square box (d) is of cast iron, and contains the 



