Author: Chas; W. Smiley

Publisher:

Published: 2015-08-05

Total Pages: 206

ISBN-13: 9781332304219

Excerpt from The Microscope, Vol. 1: An Illustrated Monthly Designed to Popularize the Subject of Microscopy, New Series (Nos; 1-12) Cloudiness or particles of dust on any part of the ocular may be detected in this way. Dust or Cloudiness on the Objective. - Employ the same ocular and objective as before, and the fly's wing as object. Focus and light well, and observe carefully the appearance. Rub glycerin on one side of a slide near the end. Hold the clean side of this end close against the objective. The image will be obscured, and cannot be made clear by focusing. Then use a clean slide, and the image may be made clear by elevating the body slightly. The obscurity produced in this way is like that caused by clouding the front-lens of the objective. Dust would make a dark patch on the image that would remain stationary while the object or ocular was moved. If too small a diaphragm is employed, only the central part of the field will be illuminated, and around the small light circle will be seen a dark ring. Relative Position of Objects or parts of the same object. - The general rule is that objects highest up come into focus last in focusing up, first in focusing down. Objects Having Plane or Irregular Outlines. - As object use three printed letters mounted in stairs in Canada balsam. The first letter is placed directly upon the slide, and covered with a small piece of glass about as thick as a slide. The second letter is placed upon this and covered in like manner. The third letter is placed upon the second thick cover and covered with an ordinary cover-glass. The letters should be as near together as possible, but not overlapping. Employ the same ocular and objective as before. Lower the tube till the objective almost touches the top letter, then look into the microscope, and slowly focus up. The lowest letter will first appear, and then, as it disappears, the middle one will appear, and so on. Focus down, and the top letter will first appear, then the middle one, etc. The relative position of objects is determined exactly in this way in practical work. Transparent Objects Having Curved Outlines. - The success of these experiments will depend entirely upon the care and skill used in preparing the objects, in lighting, and in focusing. Employ a 5 mm. (1-5 in.) or higher objective and a high ocular for all the experiments. It may be necessary to shade the object to get satisfactory results. When a diaphragm is used the opening should be small. Air Bubbles. - Prepare these by placing a drop of thin mucilage on the centre of a slide and beating it with a scalpel blade until the mucilage looks milky from the inclusion of air bubbles. Put on a cover-glass but do not press it down. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.