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.

OXY-ETHER AND HYDRO-CARBON LIGHTS 99 tap of the jet, and after a few seconds, to let air escape, turn it off again for inflammable vapour to leave the lantern. Turning it on again we apply a light, which burns in place of house-gas. All the * pure' oxygen taps, from the fork on- wards, are meanwhile turned off. It is always to be remembered that full saturation with ether vapour is the condition of silent combustion and safe- guard against explosion ; the explosive mixture with oxygen only being allowed at the jet itself. The test of this is the condition of the flame. While all is safe, this is white or yellowish-white. As oxygen increases, this changes to deep yellow, and finally to a purplish or blue colour. This last shows an explosive condition, and whenever it occurs with what stands for the hydrogen supply alone, proceedings should at once be stopped. This test refers to naked flame only. When the lime is adjusted close to the jet, even a dangerous mixture may appear to burn yellow, and therefore it is best always to light the flame first, at a distance from the lime. If it is a good light colour the lime can be adjusted and warmed, after which the oxygen is gradually turned on and adjusted in the usual manner, till the brightest light is attained. As the work proceeds, however, if it be found that the pure oxygen has to be gradually turned off, it shows that from some cause saturation is becoming more and more defective, and work should be stopped and the light put out. To proceed under such conditions is dangerous. At the end of work, the hydrogen tap of the jet may be turned off, so that the surplus oxygen ' snaps ' the jet and puts it out. The condition of safety is to turn off at the jet first, and never at the bag or cylinder till the light is out. When two lanterns or a bi-unial are worked with this light, it will often be found that the dissolver (see Chapter VIII.) will not work properly without some alteration. No oxygen bye- pass whatever must be allowed, as is often done with the H2