108 Scientific Intelligence. 
drawn by the registering crayons. As M. Arago is about to give to this 
f 
consists of two distinct parts: 1, of the Anemometer properly called, 
which is placed on a roof, tower, or it may be on a mountain, and 
which receives the different influences of the winds; 2, a Registering 
apparatus, which registers all these influences, and which is kept in the 
room of the observer. 
Anemometer properly so- 1, 
ealled.—It consists of a cylindrical box 
ABCD, (fig, 1,) at the center of which 
turns a weathercock or vane G, ona 
roof **en parasol” FHE is soldered 
to the axis of the vane. The wind- 
mill ME, can thus turn freely with the 
weathercock and is secure from the 
rains. 
The commutator connected with 
. . 
the lever L, consists of a plain me- 
order to insure the contact of this lever 
with the conductor which supplies the 
current, M. Dumoncel employs two 
metallic springs pressing constantly on 
the lever L. 
ture of the current in the 8 wires which correspond to its different 
directions. 
€ may now consider how the velocity of the wind furnishes indica 
tions. The windmill of Woltmann consists, as is known, of four wings; 
which turn the more rapidly the Stronger the wind; and the degree of 
