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.
CH. IX] TROUBLES WITH MICRO-PROJECTION 301
removed. For projection the mirror must be in place to reflect the light along the axis as for lantern slides. The change to the projection of opaque objects is almost instantaneous, but for lantern-slide projection the projection microscope must be removed and the lantern-slide objective put in place, but_the apparatus is so constructed that this is easily accomplished.
FIG. 1 66. IMPROVED, COLLEGE, BENCH LANTERN ARRANGED FOR
MICRO-PROJECTION. (Cut loaned by the Mclntosh Stereopticon Co.).
The optical bench consists of a long baseboard with the two guide rods supported by three brackets.
As each part is independent it can be changed in position or entirely removed and other apparatus put in its place, thus giving great flexibility.
TROUBLES WITH THE PROJECTION MICROSCOPE
§ 435. The source of troubles with the projection microscope are mainly the same as with the magic lantern. These have been fully discussed at the end of Chapter I (§ 62-98). See § i28a for the blowing of fuses with the arc lamp on the house system.
The special troubles with the projection microscope are almost wholly due to the smallness of the lenses necessary for micro-projection; and as the foci of these lenses are relatively short, slight changes in the position of one of the elements of the apparatus, and slight deviations from the true axis produce correspondingly great effects. It is necessary to be more exact in micro-projection, but the great fundamental principles are exactly as for the magic lantern.
§ 436. Insufficient illumination on the screen. — Besides those given in Chapter I the following may be causes : i. Too large a screen image may be attempted.