SET OF ACRYLIC PLASTIC BLOCKS 1236
Clear acrylic plastic blocks 20mm thick with bottom surface finished in white to show ray tracks and all other surfaces fully polished. The set comprises seven blocks as follows.
(a) Rectangle 70x50 mm.
(b) Triangle 90x45x45, 75mm hypotenuse.
(c) Triangle 60x60x60, 57mm side.
(d) Semi-circle 75mm diameter.
(e) Bi-convex 75mm long, curved faces,115mm radius.
(f) Bi-convex 75mm long, curved faces, 145mm radius.
(g) Bi-concave 75mm long, curved faces,115mm radius.
All packed in velvet lines box.

PERSPEX BLOCK, RECTANGULAR 1237
Rectangular of clear perspex, all faces fully polished.
Size: 115 x 60 x 20mm approximately.

PERSPEX BLOCK, SEMICIRCULAR 1238
Made of clear perspex, all faces nicely polished 80mm dia and 20mm thick approximately.

PHOTOMETER JOLLY’S 1239
Block comprising two pieces of polythene approx. 25 mm square 10 mm thick separated by tin foil, on stand behind aperture 12 mm dia.

DEMONSTRATION MODEL OF ASTRONOMICAL TELESCOPE 1241
Complete with 38mm dia lenses in metal holders mounted on wooden board which has a diagram showing the course of rays.

DEMONSTRATION MODEL OF GALLILIAN TELESCOPE 1242
Complete with 38mm double concave lens eyepiece and a double concave lens objective in metal holder mounted on wooden board having a diagram showing the course of rays.

ASTRONOMICAL TELESCOPE 1244
50mm dia achromatic objective glass, 10x Ramsden eyepiece, focusing by rack and pinion. Supplied with a folding tripod stand with adjustable height.

RAY TRACK APPARATUS 1245
Wood board with matt white surfaces, mounted on plastic feet carries a circular scale with 0-360° four quadrants 0-90° graduated every 2°, removable turntable 170 mm dia. with 2 lines at right angles and a Ray Box with a 12V, 24W bulb. Supplied with a cylindrical convex lens focal length 75 mm and two double screens, giving one wide slit and one each single, three and five slits.

RAY OPTICS BOX 1246
Black finish metal box, with 12V 24W straight filament lamp. The lamp holder, with 1mt. of twin flex wire is mounted in metal bridge piece. The enameled steel body has slots to support a cylindrical lens and a triple slit screen. Extra slots are provided for filters. Dimensions 182 x 61 x 115mm high. The box is supplied complete with lamp and triple slit but without lenses or filters.

RAY OPTICS KIT 1247
Kit consists of two lamp holders, each in metal shade with two axial slots and mounted on metal support rod. Holder complete with approximately 1.2m 2-wire P.V.C. covered cable and 12V, 24W axial filament lamp. One each right and left hand cylindrical lamp shields, in matt black finish light alloy sheet with slot parallel to axis. Two black “combs”, with 17 equi-speed parallel slots, two black plastic plates, each with single and triple slits, two comb and plate holders, a spring loaded clip mounted on metal support bracket, four metal light-barriers, four each plano convex cylindrical lenses, 50 x 50mm, +7D, two each cylindrical lenses 50x50mm, respectively, plano-convex +10D, +17D, plano concave -17D.

PIN HOLE CAMERA 1248
To illustrate images produced by small apertures. Comprising a polished wooden box with a ground glass screen at one end and a hole at the other.

PINHOLE CAMERA KIT 1249
The kit consists of the following items.
8 cardboard boxes 150 x 100 x 100 mm with hole, screen and lid.
50 sheets of black paper 200 x 250 mm
1 lamp 200WATTS
1 mounted lamp holder with flex
1 packet of pins

SET OF COLOUR FILTERS 1250
A set of three primary and four secondary colour filters suitable for use with ray box mounted in card board frame size 50 x 50 mm. Plastic mounts also available.

NEWTON’S COLOUR DlSC APPARATUS. 1251
Demonstrates that mixed spectral colours produce white when rotated rapidly. Comprises of a metal disc 150mm dia having 7 colours (VIBGYOR) in their right proportions, mounted on a metal stand.