. Beck microscopes. Microscopes. Outfit for Ultra This is mounted complete on an optical bench consisting of a strong steel bar (A) 24 in long, carried on 2 cross bars (B), sup- ported on 2 levelling screws (C). Projecting over one end of the bar is fixed an automatic arc lamp (D) 5 to 10 amps, which has the positive carbon (E) horizontal and the negative carbon vertical. The crater of the arc is thus direct- ly facing the optic axis of the bench. The arc lamp is enclosed in a lamp house (F) with side doors and with a small tubular aperture (H) in the front to allow the light to e
. Beck microscopes. Microscopes. Outfit for Ultra This is mounted complete on an optical bench consisting of a strong steel bar (A) 24 in long, carried on 2 cross bars (B), sup- ported on 2 levelling screws (C). Projecting over one end of the bar is fixed an automatic arc lamp (D) 5 to 10 amps, which has the positive carbon (E) horizontal and the negative carbon vertical. The crater of the arc is thus direct- ly facing the optic axis of the bench. The arc lamp is enclosed in a lamp house (F) with side doors and with a small tubular aperture (H) in the front to allow the light to emerge. The lamp is also provided with raising and lowering motions (G) and a small lateral movement swinging on the pivot (K). A series of fittings slide along the steel bar. The first (L) carries an achromatic lens system for focussing an image of the crater of the arc upon the fitting (M) carrying an adjustable slit which is provided with a rotating movement and side cheeks for limiting the length of the slit. A fitting (N) carries a 32 m/m achromatic lens system by which an image of the slit is projected along the optic axis 5 times smaller than the slit. At a distance of about 280 m/m from this lens system a special microscope object glass, 25 m/m focus, .28 , is carried upon another fitting (O). This object glass has a working distance of 9 m/m and allows of the use of the highest power lenses without touching the mount of the observing lens. Between the slit and the projecting lens an adjustable chisel edge is carried on the fitting (P) by which the beam of light can be restricted in height. The adjustments having been made on the optical bench to ensure proper centring the whole bench can be adjusted vertically by the front levelling screw (C) and laterally by moving the whole bench. The levelling screws stand on 3 smooth metal plates, the front one (R) of which is provided with a lateral screw adjustment. The size of the final ribbon of light can be varied by arrang
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