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.
448 HIGH-SPEED PHOTOGRAPHY November
products and should be ordered from your local photographic dealer. It is essential that all orders for 16-mm film to be used in high-speed cameras specify, "Spooled for High-Speed Cameras." Film orders for the 8-Mm Fastax camera should specify, "Spooled for 8-Mm Fastax Camera." This assures the user that he will receive fresh film of highest emulsion speed and that it will be correctly perforated and spooled on aluminum spools without core clips. The use of other than aluminum spools will impair the dynamic balance of the camera, and should a core clip become detached at the end of a run, it would seriously damage the camera mechanism.
The Linagraph Ortho and the Linagraph Pan are used in highspeed cameras when modified for use as an oscilloscope camera. Methods of high-speed oscillography will be discussed later.
In making schlieren pictures several methods can be used. The first method is to use an incandescent lamp and image the filament of the lamp at the objective lens. The subject will pass between the lamp and the objective. In order to focus the lamp at the lens a spherical mirror can be placed back of the lamp. By adjusting the relationship between the mirror and the lamp it is easily possible to secure the image of the filament at the lens. The objective lens is then focused at the subject plane and not at the light source.
A second method is to replace the spherical mirror with one or two condensing lenses in order to image the light source at the objective lens.
A third method which has just recently been developed by Edgerton and his associates has been to link the flashing lamp with the Kodak and Fastax high-speed cameras. The flashing lamp which they have developed for this purpose will be ideal for schlieren pictures, for the actual time of flash is 1 microsecond and it can be operated up to frequencies of 10 kilocycles. In this case the incandescent lamp is replaced by the new flashing lamp and there is a triggering device in the high-speed camera which allows the lamp to be fired when the picture frame is on line with the optical axis of the complete system. This type of light source is particularly adaptable for making schlieren pictures for the effective time of exposure is reduced considerably. The two first-mentioned systems would not resolve velocities of shock waves comparable with that of the method just mentioned.
The third method can also be used to illuminate high-speed photographic subjects from the front. This lamp will adequately light a field size 12 X 12 feet. There are several advantages in using this