234 THE STRUCTURE AND LIFE OF BIRDS cuap, 
These were by no means so complete as we had 
hoped they would be, owing to an accident to our ane- 
mometer. This small instrument, which presents sails 
like those of a windmill to the wind, and, as it turns, 
registers the length of the stream of air that has acted 
on it in the allotted time, was all that was required 
for the lower levels. 
The place chosen, New Romney sands on the coast 
of Kent, has exceptional advantages for such experi- 
ments. There are no hills or cliffs to tilt the wind 
upwards, no trees or other obstacles to make it play 
tricks, so that it was a horizontal wind without com- 
plications that was experimented on. 
The following are averages made out from four 
series of experiments :— 
Velocity of the wind 
Altitude. per minute. 
2inches ... ey sa aoe ... 515 feet. 
Ifoot... ie ne Pe sas F364 5, 
2 feet ma ane ae a «ws 770 5 
4 feet ste sie wie ek . 918, 
7 feet 6inches ... oo aie ec GO2R 4s 
As the wind comes in gusts, it is necessary, if the 
results are to be trustworthy, to make a number of 
measurements and strike averages. The figures show 
that the rate of increase diminishes as you ascend, the 
difference in velocity at two inches from the ground 
and one foot being very great. The following are the 
averages from only two series :— 
Velocity of the wind 
Altitude. per minute. 
7 feet 6inches ... His oak ... 1,375 feet. 
gfeet 6inches ... oe sae 21,4578 95 
The plan for measuring the velocity of the wind at 
