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.
zo
ZA
2.37
/9
2Z
^7
d2
:i,j5
zz
^2
£7
Z3"
Zo
Z.^sr
^^
2o..ir
Fig. 6 — Diagram showing foot candle intensities on screen having an area of 27.75 sq. ft.; 693 lumens
nation is steady the eye can be more comfortably focused on the picture than where the light intensity is varying as is always the case where arcs are used.
A comparison of the intensities obtained on a screen with a 40 ampere direct current arc and 1200 watt lamp is shown in Fig. 7. These intensities give approximately equally satisfactory pictures; that is, the audience could not determine which lamp was in use. In this test the illuminometer was arranged so that its field of view covered practically the entire surface of the screen and readings were taken at intervals of 15 seconds for a period of 10 minutes. The scale used is an arbitrary scale and does not show the actual foot candle values of the light reflected from the screen.
LAMP-HOUSE EQUIPMENT
When the filament of an incandescent lamp is once placed at the proper point in the optical system it remains in this position for the life of the lamp. Changes in the focus are necessary only when lamps are changed. For this reason it is possible to adjust a lamp so that the filament occupies a predetermined position with respect to a base plate or holder which can be slipped into the lamp-house or removed at will. After the filament has been adjusted with respect to this holder, the lamp and holder can be very quickly placed in service in the machine in case of a burnout. The only thing necessary is to remove the burned out lamp and holder and substitute the new holder with its lamp properly adjusted.
44