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.
CHRONO-PHOTOQRAPHY. b1 longer plate, shifting between each exposure, employed. Another method of separating the images was to inter- pose a revolving mirror between lens and object. This arrangement is interesting from the fact that it has recently been suggested to use the same device in a reverse manner, causing it to project separated pictures on to one place on the screen, while the original arrangement gave separated pictures on the plate from an original which remained in one place. It cannot be postulated too emphatically that, even at this early date, nothing was required but a flexible and transparent film, capable of receiving an emulsion of increased sensitiveness, in order that the modern living picture might spring into existence; but twenty years were fated to elapse before these necessities were placed at the disposal of the photographic world. Therefore nothing was available except glass plates, and these were naturally used in circular form in order that as long a series as possible might be secured. In the year 1874, however, an opportunity occurred of photographing a very brilliantly lit object of great interest; and a desire on the part of M. Janssen to obtain a chronographic photo-record of the Transit of Venus across the sun's disc caused him to invent his Photo- graphic Revolver and suc- cessfully employ it in the far-off regions of Japan. This instrument was placed under cover as shown in Fig. 59, and when in use was directed on a heliostat, which served to keep the image stationary by neutralising the sun's apparent motion. With it forty-eight images were taken around the edge of a circular plate in the space of seventy-two seconds, Fig. 59.