Improved Construction of the Anemometer. 
477 
The advantages obtained by this construction of instrument are 
stated by the inventor to be as follows: — 
1st. The scale of time is five limes as large as Mr. Osier's, 
within equal-sized sheets. 
2d. The register of direction is more accurate, an equal quan- 
tity of paper being used, and it can never fail to register. 
3d. The data are more comprehensive. 
It consists of a double vane 
(shaped like a truncated 
cone,) the small ends being 
secured to a vertical brass 
tube b, (see the cut) v^'hich, 
passing through the roof of 
the building where it is 
mounted, rest, at its lower 
end, in a hollow socket fixed 
on a table a, that supports 
the instrument. To the low- 
er end of this shaft is attached 
a cylinder, which rests upon 
the table, but follows every 
movement of the shaft. Its up- 
per face is cut obliquely, and 
around its peripherythe points 
of the compass are marked. 
In the centre of the shaft &, is a rod, which, at its upper end, car- 
ries a fan-wheel, and at its lower end is provided with a worm or 
endless screw. This worm takes into a worm-wheel mounted in 
bearings on the underneath part of the table a; and on the worm- 
wheel shaft is another worm for driving, through the agency of 
a wheel and screw-thread on a horizontal shaft, the axle of the 
drum c. Between the drum c, and the oblique-faced cylinder, a 
vertical guide is fixed firmly on the table, for the purpose of car- 
rying three pencils, one under the other; the two upper of which 
rise and fall, as will be presently explained. To the top pencil 
an arm, pendent from one end of a vibrating lever, is attached. 
This lever is supported by a bracket from the table, and at its other 
and it is connected by a pendent-arm with the minute-hand of a 
clock. As the socket of the second pencil rides on the face of the 
cylinder attached to the shaft b, it is made to rise and fall by the 
rotation of that cylinder; and the lowest pencil is acted upon only 
when the eccentric portion of a ring e, on the cylinder, comes 
round, and forces it forward. 
The action of the wind on the fan-wheel causes the apparatus 
to rotate; and the drum c, being furnished with paper, the miles 
of wind, its direction, and velocity at all hours, are registered 
Fia. 35 — Anemometer. 
