This done he extends his enormous pinions 2 and sails majestically along, seldom deigning to flap his wings, the breeze doing the work for him.
The toothed wheels give a slightly better efficiency, but the worm gear is somewhat smoother in its action and entirely silent; the noise of gearing can, however, be considerably reduced by careful machining of the teeth, as is now always done, and also by the use of pinions made of rawhide leather or other non-resonant material.
When quick-running metal pinions are used they are arranged to run in closed oil-baths.
Leather pinions must be protected from rats, which eat them freely.
On such lines the beginning of a rack section is provided with a piece of rack mounted on springs, so that the pinions of the engine engage smoothly with the teeth.
For example, on the surface of a shibuichi box-lid we see the backs of a flock of geese chiselled in silver, and when the lid is opened, their breasts and the under-sides of their pinions appear.
These screws are turned from the eye-end by bevelled wheels and pinions, the latter connected with the handles a', b'.
At the centre of are rotated by pinions driven by hydraulic engines working in steel sectors 42 ft.
As illustrative examples of the form of wings alluded to, those of the beetle, bee and fly may be cited - the pinions in those insects acting as helices, or twisted levers, and ' Revue des tours scientifiques de la France et del' Etranger, 1869.
In registering the movements of the wings the tips and margins of the pinions were, by an ingenious modification, employed as the styles or pens.
If such comparison be made, it will be found that the pinions in some instances diminish while the bodies increase, and the converse.
There are also two vertical racks, one at each end of the casing, in connexion with - the two springs, and these actuate pinions on the axle of the drum and cause it to revolve as the springs extend.
Next day the young phoenix is already feathered; on the third day his pinions are full grown, he salutes the priest and flies away.
The hawk is aerial brother of the wave which he sails over and surveys, those his perfect air-inflated wings answering to the elemental unfledged pinions of the sea.