We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
CHEONO-PHOTOGRAPHY. 65 teeth also locked the wheel attached to the spool. This arrangement would certainly have been unsuitable for rapid working, if only on account of strain on the film, but it is interesting as an example of how an idea may be " in the air," for this spring roller, allowed to act intermittently by means of an escapement tooth, was the feature of the apparatus patented in the next year by Messrs. W. Friese-Greene and M. Evans, to whom must be adjudged the honour of having first introduced a practical instrument capable of securing a record of any event and suitable for subsequent reproduction of a moving picture of the past occurrence. Their joint specification was filed on the 2ist of June, 1889; on the 25th of February, i8go, an actual instru- ment was shown before the Bath Photographic Society, and at that date their projection apparatus was in the maker's hands. Their camera was capable of securing three hundred exposures at the rate of ten in each second, though this speed could be increased con- siderably if required. The construction of this piece of apparatus was most ingenious and so simple that a short description will suffice. The film passed from one spool over a plate, which held it flat for exposure, and then on to a second spool by which it was wound and stored. Both spools were driven at an equal speed from the main-shaft, and thus the film would have passed the exposure opening with a steady and uniform motion had it not been that a roller was interposed between the light-aperture and the receiving spool. This roller contained a spring, continually wound from the main-shaft. The spring would have forced the roller round as fast as it was wound up but that on the roller's edge was placed an escapement tooth which rested against a cam. This cam (itself in continual rotation) stopped the roller from turning, but a gap in its edge allowed the escapement tooth to pass once in F