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.
6 INTRODUCTION
1. The optical parts should be arranged on one longitudinal
axis and fixed in that position, except that the projection objective must be movable along the axis for focusing.
2. The radiant or source of light should be adjustable in every
direction to insure proper centering of the light along the optic axis, and to insure the proper relative position of the source of light and the condenser.
3 . The object carrier for lantern slides is preferably fixed in one
position; but the stage of the microscope and the object holder of most other kinds of apparatus should be movable along the longitudinal axis so that the object can be put in the cone of light where it will be fully and most brilliantly lighted.
4. The parts should be constructed so that either (a) it makes
no difference how they arc placed or (b) so that they cannot be put together wrong. (See footnotes to 4-5, p. 7).
5. Every part of the apparatus should be dull black to avoid
reflections.
Of course for experimental apparatus the more adjustable each part is the greater are its possibilities, but for apparatus to use for definite purposes we believe that no unnecessary adjustments should be possible.
The custom followed by many manufacturers of sending an illustrated pamphlet giving instructions for installing and using their apparatus, is wholly commendable. In addition it would be advisable in some cases to attach tags to the different parts, stating their purpose and connections (fig. 45).
All of the apparatus and all of the experiments discussed in this book have been personally tested or observed by us to make sure that they will work; and we have tried to give directions and methods which arc intelligible, and which will most easily produce the desired results.
Finally, the authors of this book most earnestly advise any one who is to use projection apparatus to go to some place where the facilities arc abundant, and where there is someone skillful in using them. This will give him a standard of what can be accom