114 A NEW SELF-REGISTERING ANEMOMETER AND 
fifty-six teeth. The axis of this wheel carries a wheel with a grooved 
m and a light arm which is free to move round it; a spring 
= this pressed up to the wheel; the end of this arm projects 
beyond the edge of the groove, and to it the wire workin ing the 
velocity-pen is attached in such a way that it hangs in front of the 
groove, and when the wheel is turned round by the motion of the 
cups, and the pin in the side of it catches the arm mp carries it 
round, the wire falls into the groove and is wound up one turn on 
the wheel. As the wheel continues to revolve, : br the arm 
against an unlocking part which throws it o e pin, and the 
weight o of the wire at once pulls it round to a starting-point. 
For each 20 miles of wind, therefore, the wire is drawn up 4 inches 
and suddenly let go. 
In placing the cylinder, a convenient position for reference 
at all times was considered of paramount importance. The o 
new one on the ground floor, but as this was 58 feet below the 
leads aid 75 feet from the vane and cups, it became Seu to 
devise some means of carrying the motion down whic d give 
the least friction, and at the same time be rigid seca is convey 
every oscillation of the vane. A suitable material for this was 
found in steel wire, and it was applied in the following way :— 
oles having been cut in the four floors, a wire was taken 
to the grooved wheel on the horizonal axis of the bevel- liege 
passed one and a half times round it and then down the tower 
again, where it was passed through the saa on a weight of 5 |b., 
and then fastened to the other end, thus making a double length 
of wire from the vane to the floor, 7.e., 75 feet, arranged for endless 
motion, so that it does not matter how often the vane turns round, 
it will not come to the limit of motion allowed by the wire. This 
motion was made to record itself on the vertical cylinder by 
attaching the wire to a very light frame made of {-inch brass 
ubing, and carrying four pencils. The me ans of attaching this to 
factory than I anticipated, ait I dated the elasticity of such a 
length of wire might allow the vane to move without moving the 
pencil, but it does not,—the strain of the weight is sufficient to keep 
the wire straight, and as it has no friction to overcome ex 
moves with the greatest ease and responds to every motion of the 
vane. 
The cylinder for receiving the record is on a vertical axis, and is 
8 inches in diamete eter and 10 inches long, and is turned by the clock 
