WITH THE MICROSCOPE. 241 



Beechy, in his paper on Microscopic Photography, recommends very 

 strongly the oxy hydrogen light, and indicates a very simple method 

 by which an ordinary good magic lantern can at a small expense 

 be converted into use as a microscope camera for powers from 

 i inch to the |- inch. Dr. Woodward's arrangement will be under- 

 stood if pi. LI I be referred to. 



328. Camera applied to the ordinary Microscope. We may now 

 consider the plans for employing the microscope and camera united. 

 Mr. Shadbolt recommends the draw tube, if any, to be removed, and 

 its place supplied with a lining of black velvet. The microscope is 

 fixed horizontally on a board or table, and the body made to cor- 

 respond to the centre of the aperture left on the removal of the 

 lenses from the brass setting of an ordinary camera. The intervening 

 space being closed in such a way as to exclude all entrance of 

 extraneous light. The draw chamber of the camera is employed to 

 vary the distance of the image from its object, but is usually deficient 

 in length, hence some plan for elongating this chamber is needed. 

 Many complain that when using the microscope in this way, some 

 uncertainty in the centering, and liability to derangement when 

 exchanging the focussing screen for the prepared plate are expe- 

 rienced. Gerlach adopts a very different arrangement. The camera 

 is adapted to the top of the tube of the microscope which is placed 

 in an upright position, pi. LIII, fig. 339. 



329. Dr. niaddox's Camera, - The instrument proposed by 

 Dr. Maddox, and used by him consists of a microscope having a 

 compass-joint at the lower end of the stem furnished with coarse 

 screws, &c. The stage slides along the stem, and can be clamped 

 to it by a binding screw against a guide that runs along its length. 

 This stage is provided with small rectangular movements attached 

 to the part holding the object slide, and to its opposite side is 

 fixed a stout tube to hold an achromatic or some form of con- 

 denser. The main part of the stem is hollow, and receives a 

 strong tube furnished nearly in its entire length with a slot that 

 works on an internal guide fixed inside the stem. Th's tube carries 

 at its near end an arm, at right angles to which a tube about 

 five inches long is screwed on the near side, and on the opposite 

 side an adapter is fitted to receive the screw-end of the objective. 

 An approximate focus is effected by sliding the stage along the stem, 

 and the fine motion by a graduated milled-headed screw-pin. This 

 pin passes through the tube to which the arm is fastened, and 

 engages in a thread cut in the solid end of the stem. A spiral wire 

 coiled in the inner tube reacts on the arm when the milled-headed 

 screw is withdrawn. 



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