The University Micro-Projector.

For micro-projection on a sufficiently large scale for class purposes, including work with high powers, a very rigid construction is essential and a powerful source of light must be employed to enable a critically defined and brilliant picture to be shown. If an apparatus is employed consisting of a separate microscope and illuminating apparatus, it is practically impossible to keep the various parts in continuous adjustment, and to be convenient and satisfactory in use such an apparatus should be made in a complete unit to ensure its stability.

No. 4954

The general design of this projector can be seen from the illustration—and it will be seen that the whole of the parts are carried on a heavy casting which gives it the necessary solidity. The illuminant is an arc lamp which is enclosed in a well ventilated lamp-house with a large door on one side to allow of access to the arc lamp. The light is concentrated by means of a condenser fitted to the front of the lamp-house and is then passed through a cooling trough to the substage condenser on the microscope. This condenser consists of an optical system for use with low powers, and above it, fitting in a slide in the stage, is a second optical system which, when slid into position above the low power condenser, renders it suitable for high powers. An iris diaphragm and a focussing adjustment are provided to the condenser. From this condenser the light is passed through the specimen and through the microscope object glass and eyepiece and projected on to the screen.

The microscope itself has all necessary adjustments including coarse and fine focussing adjustments. Standard object glasses and eyepieces are used. The object glasses can be fitted into a double or triple revolving nosepiece. The microscope is hinged so that it can be used either horizontal or vertical. For ordinary objects it is used in its horizontal position, but where objects in fluids are being examined, it is placed in its vertical position. A mirror is then fitted below the

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Le texte affiché peut comporter un certain nombre d'erreurs. En effet, le mode texte de ce document a été généré de façon automatique par un programme de reconnaissance optique de caractères (OCR). Le taux de reconnaissance estimé pour cette page est de 99,71 %.

La langue de reconnaissance de l'OCR est l'Anglais.

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