NEWTON’S RING APPARATUS 1252
Comprises a plano-convex lens 60mm dia and l00cm focal length. On a flat glass plate equal dia. Both enclosed in a ring frame with compression adjusting screws.

REFRACTIVE INDEX OF A LIQUID BY CRITICAL ANGLE METHOD 1253
The apparatus consists of a cemented glass trough, air cell rotatable by knob carrying pointer on circular scale graduated 360°. Fitted on bridge.

SPECTROSCOPE, Simple (Direct Vision, Hand) 1254
A wide spectrum through 10x10mm size, 3 element type optical glass prism, telescopic focusing brass body, precision slit adjustable by knurled head rotatable ring.

SPECTROSCOPES WITH SCALE (Direct Vision) 1255
Direct wave length readings 400nm to 750nm each div. represents 5nm, with sodium D-line scale and spectrum is viewed in the same field. Precision slit and focusing control with D-line adjustments for error free readings.

LIGHT BOX AND OPTICAL SET (HODSON LIGHTBOX) 1256
This kit contains a light box and collimating lens, together with a full set of precision lenses and prisms, colour filters, coloured cards, half round and parabolic mirrors, spare lamp, comprehensive instruction and experiment manual. Two integral hinged mirrors permit the blending of 3 colours on a screen for study of colour mixing. The precision and unique design is virtually unbreakable. Power requirements 12V A.C. or D.C. at 3 amps. All parts are available separately. Spares for Above:
(a) Only light box with lamp and slits
(b) Lens and mirror pack
(c) Set of colour filters
(d) Spare lamp

DIFFRACTION GRATINGS 1257
Photographic replica gratings mounted on plate glass and suitable for visual. Grating size, 25 x 25mm, on glass plate 50 x 38mm. The gratings are of:
(a) 300 lines/mm
(b) 600lines/mm.
(c) 2400lines/inch.
(d) 7500lines/inch.
(e) 15000lines/inch.

ROTATABLE OPTICAL DISC HARTLEY'S 1258
A 30 cm dia., white painted steel disc marked from 0 to 360° at every 1°, with centre mark, on a stable cast iron base. The main disc and the lamp house (with 12V, 24W bulbs) can be rotated and held in any desired position. With the lamp house, a rotatable disc with single, double, triple and quadruple slits and with adjustable lens carrier with lens for divergent, parallel or convergent light beams is provided. Optical elements provided for reflection are 50 x 25 mm, plane glass mirror, and a polished plated metal cylindrical mirror. Optical element for refraction is semi-circular, bi-convex, bi-concave, right angle prism and trapezoidal acrylic blocks. These Optical elements have powerful magnets attached for fixing of blocks to the disc.

METERSTICK OPTICAL BENCH SET 1259
Sufficient for optical experients in high school physics. Set Includes 2 end supports, 2 Lens holders, object marker, screen, screen with millimeter scale, Complete with Meter Stick.

OPTICAL BENCH WOODEN 1260
Wooden base with 1mt. scale graduated in mm. Complete with two lens holders, one candle holder, pin hole plate, ground glass screen, wire gauze screen and a needle stand with index mark.

SODIUM LAMP HOUSE AND TRANSFORMER 1261
Heavy base with 500 x 12.5 mm anodized aluminum rod (upright) carrying lamp house and aperture with holder adjustable for height. Complete with transformer but without Sodium Lamp.

OPTICAL BENCH, 1 meter 1264
One meter long, for advanced research work consists of two rods, one stainless steel and one chrome plated. The stainless rod is engine divided in mm. These are supported on heavy cast iron feet, with leveling screws. Four special designed metal sliders having a fine index mark enables reading to be taken on the scale with ease and accuracy. The sliders are machined metal so they slide accurately and smoothly on the’ bed. Two of the sliders have transverse slow motion adjustment. Complete with 6 accessories (two lens holders, two optical pins; one candle holder and one screen ground glass).

OPTICAL BENCH (1½ meter) 1264-A
Same as above, but 1½ meter long.

CROSS WIRES 1268
A circular blacked metal screen 75mm dia, with a 10mm dia aperture and cross wires of 26 s.w.g. Mounted on a 6 mm brass rod giving a center height of 80 mm approx.