1909-10.] Proposal for an Anemometer. 389 
appear likely to be suitable (see fig. 2). The horizontal axis passes 
back into a covered vessel B and there rests on ball-bearings at C 
and G, and has the thrust of the wind taken by a hard-steel end D. 
At E the axis carries a small “ lantern ” or toothed-wheel gearing 
which engages with the horizontal toothed wheel F. F is therefore 
made to rotate round its vertical axis by the spinning of the wind- 
wheel. The hollow vessel B is at the top of, and is rigidly attached 
to, the hollow vertical axis of the wind-vane, which is prolonged 
upwards above the vane. Through this hollow axis of the vane the 
vertical axis of the toothed wheel passes right down till both axes 
enter the room in which the registering apparatus is. Here the lower 
end of the axis of F drives a spur-wheel gearing which causes the 
sphere to turn. 
Fig. 2. 
It is of importance to diminish, as far as may be, any frictional resistance 
which may hinder either the spinning of the wind-wheel or the setting 
of the vane. Fluid friction is no great disadvantage, as it may be taken 
to be proportional to the speed for the small speeds involved ; and it can 
be used to damp the oscillations to which a wind-vane is liable even in 
steady winds. 
To diminish the frictional resistance to the spinning of the toothed 
wheel F and its axis, the bottom of the vessel B is hollowed out into the 
shape of a surface of revolution, which contains oil ; while the wheel F 
bulges downwards into the oil and is buoyed up by it. The vertical axis 
of F need be only a fairly stout wire. The whole weight of F and its 
axis can easily be supported in this way. 
In the case of the axis of the vane, the following device is employed. 
To give due exposure to the vane and wheel it is proposed to mount the 
