Optical projection: a treatise on the use of the lantern in exhibition and scientific demonstration (1906)

Record Details:

Something wrong or inaccurate about this page? Let us Know!

Thanks for helping us continually improve the quality of the Lantern search engine for all of our users! We have millions of scanned pages, so user reports are incredibly helpful for us to identify places where we can improve and update the metadata.

Please describe the issue below, and click "Submit" to send your comments to our team! If you'd prefer, you can also send us an email to mhdl@commarts.wisc.edu with your comments.




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.

106 OPTICAL PROJECTION this, a programme should be written if this method is adopted; but as the sudden splitting of a lime might possibly upset the order, it is better to carry out the system thoroughly, and register both lantern and slides; moreover, the lantern registration is done once for all. For dissolving views with oil lanterns, these must be used side by side, and both lamps must be kept full on, as it would be impossible to turn the lights up and down. Generally a shade, going off at one side into taper teeth like a comb, travels across each lantern nozzle, so as to cover and uncover each in turn; the two shades being connected so that as one covers, the other uncovers. Plans have been published for using one oil lantern over the other, but none such are really safe, or tolerable in use. 58. Dissolving Taps.—Two lanterns with Argand gas- burners will work dissolving views very well on a small scale. The lanterns must still be side by side ; but the dissolving can in this case be done by a tap which turns one light down whilst the other is turned up, both lamps being ' on' whilst the tap is half-way. Such a tap is additional to the tap on the burner itself, and is known as the ' dissolving-tap.' In this case it is what is called a * three-way tap,' shown in fig. 59, there being three branches. The centre one comes from the gas supply, and the lever of the tap directs this into one or the other of the two channels, the amount . 59.-rLe.way Tap bein g regulated by their own taps. A similar tap is used for dissolving the oxy-spirit jet described on p. 46, but in this case the tap governs the oxygen supply, the spirit-flame being left on. This flame is too weak to give any perceptible image of the ' dead' slide upon the