Sprocket

Definition and stakes

Alex Schwalbach,  The Modern Bicycle and Its Accessories

“ The Liberty makers have brought out a sprocket with a change in the form of the teeth which is so slight that it hardly shows in a cut and is not even noticed on the bicycle itself at a careless glance. The change consists in cutting down most of the teeth in height and thickness, so that only each fifth tooth acts in the driving, the intermediate teeth serving only as guides to keep the chain in track. ”
Source: Gutenberg

The Boy Mechanic, Book 2: 1000 Things for Boys to Do

“ These projections can be pins or small staples, but they must not be over 1/16 in. in size. The base of the sprockets must fit the hole in the film snugly, but the points should be slightly rounding, so that they will easily enter the perforations. When the upper sprocket, which is approaching the film, engages a perforation, just below the upper partition, it will carry the film downward until the sprocket disengages from the perforation at the lower partition. The distance of travel must be exactly 3/4 in., as that is the height of each picture. ”
Source: Gutenberg

Edward Step,  Wayside and Woodland Trees: A pocket guide to the British sylva

“ Although we are compelled to class the Spruce among introduced species, it can lay claim to have been one of the older forest trees of Britain, for the upper beds of the Tertiary formations contain abundant evidence that the Spruce was a native here when those strata were laid down. Of its modern introduction there is no record, but from mention of it by Turner in his "Names of Herbes in Greke, Latin, Englishe, etc.," we know that it was at some date anterior to the publication of that work (1548) . ”
Source: Gutenberg

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