A bakelite ring or bobbin is of 165 mm diameter with 3 windings of 2, 50, & 500 turns. The magnetometer is supported on a brass tube fitted on an ebonite plate which is free to revolve in the base of the instrument. The magnetometer & the ring can both be rotated independently of the base which is with levelling screws. The compass box consists of a bakelite base with metal dial of diameter 100 mm graduated in degrees & with anti parallax mirror. Cobalt steel magnet & aluminium pointer are mounted on special synthetic sapphire. The needle moves on special pivot. This combination makes the needle virtually frictionless. 

GWL- A

Solenoid (Helix), Iron Core: For studying magnetic induction properties produced by electric current and the effect of an iron core. Consists of plastic spool with windings of enameled copper wire having brass binding posts on square end supports. Includes a soft iron core rod of diameter 18 cm.

GWL- B

Solenoid (Helix) Air Core: To provide external magnetic field where required and to change the rate of magnetic flux passing through a coil.

Consists of a plastic spool with windings of insulated copper. End plates have brass bindings posts. Capacity 10 amperes when used intermittently and 5 amperes when used continuously.

GWL- A

Induction Coil: The primaries are wound with thicker copper enamelled covered wire on letherite pipe in two layers. The secondary coils are divided into two parts & are given heavy insulation. Each layer is wound in a cover of butter paper & are completing the winding, the entire is dipped into hot wax to seal each layer against moisture effect. The coils are housed in a teakwood base, voltage tested condensers are fitted inside the wooden polished base. Handles to get the spark are fitted on it & make or break points are of silver. One point is adjustable to get any cycle. On/off reversing switch commutator working on 6 to 12 V DC.

GWL- B

Dissectible Induction Coil: Most suitable for demonstration. Secondary coil & capacitor can be easily separated out. With arrangements for disconnecting & capacitor, while in operation. All connections clearly visible. Spark length 25 mm. 

Telescope Model, Astronomical: Comprising a convex lens 38 mm diameter & 150 mm focal length, mounted in a plastic tube 400 x 50 mm diameter, & a double convex lens 50 mm diameter & 500mm focal length, mounted in a tube 400 x 55 mm diameter. The smaller tube is located in the large tube my means of foam plastic rings which provide an effective sliding light seal. 

Telescope Model, Terrestrial: Same as 108.39 but with plano concave eye piece lens to provide erect image. 

Astronomical Telescope: Reflecting type, fitted with about 45 mm dia achromatic objective having focal length of about 450 mm. Focusing is provided by rack & pinion. Complete with carrying case with the metallic three legged folding type tripod stand. 

Reading Telescope: Designed for general laboratory work. The telescope is mounted on 18 mm diameter, pillar 450 mm long fitted on a heavy tripod base. The telescope can be rotated both in vertical as well as horizontal plane. It is fitted with 180 mm focus achromatic object with 25 mm clear aperture , 10x ramsden eye piece with cross wire. The telescope is focused by rack & pinion & has a range from one meter to infinity; with perspex scale & its attachment. 

Reflecting Telescope: A high quality instrument with a resolving power of 1.5 seconds. The 100 mm (4 inch) diameter, 1000 mm focal length mirror gives relatively more light & less chromatic aberration than an equivalent refractor. Magnifications of upto 250x are obtainable. The telescope has an equatorial mount with hour and declination circle & micro adjustments with flexible connections to avoid vibrations. The whole is mounted on a heavy 1.52 m tripod with an accessory tray. Supplied complete with two interchangeable eye lenses 6 mm & 20 mm, a 2x Barlow lens, sun filter, moon filter, a 5×24 star finder telescope (with mount on main telescope body), a solar aperture cap & an instruction booklet with space & moon maps.

Kit consists of two lamp holders, each in metal shade with two axial slots & mounted on metal support rod. Holder complete with approx. 1.2m 2 wire P.V.C. covered cable & 12V 24W axial filament lamp. One each right & left hand cylindrical lamp shields, in matt black ‘combs’; with 17 equispaced parallel slots, Two black plastic plates, each with single & triple slits, two comb & plate holders, a spring loaded clip mounted on metal support bracket, 4 metal light barriers, 4 each plano convex cylindrical lenses, 50 x 50 mm, +7D, two each cylindrical lenses 50 x 50 mm respectively, plano convex +10D, +17D, plano concave -17D. 

To demonstrate unequal expansion. Metals of different expansion coefficients Are rolled in form of a strip. 

Calorimeters Copper/ Aluminium: One piece spinning with parallel sides & rolled rim. Type A) B) Size 75 x 50 mm 100 x 75 mm Available in both Copper & Aluminium.

Calorimeter Set: A complete set comprising the following : 1 copper calorimeter 75 x 50 mm 1 wooden outer box with felt lining 100 x 75 mm approx. 1 sliding wooden cover for outer box 1 copper stirrer with loop to fit inside the copper calorimeter 1 thermometer holder made of brass, removable

Calorimeter Set Copper: Consisting of spun copper cylinder contained within a large 75 mm diameter x 100 mm aluminium outer vessel with 10 mm of insulating material between. Supplied with wooden cover for outer vessel with bung for mounting thermometer support clip. Dimensions: 110 mm x 200 mm overall.

Joule’s Calorimeter: For determining the specific heat capacity of liquid by electrical method. Consisting of a nickel plated copper vessel 75 x 50 mm size with outer vessel of teak wood fitted with bakelite top with hole for thermometer. The terminals connected to a coil of wire (for current up to 3 amps.) are fitted, complete with stirrer & outer teakwood vessel.

Metal Block Calorimeters : For experimental determination of the specific heat capacity of different metals. Cylindrical metal blocks of mass 1 kg; adjusted to accuracy of ±2%. Each block drilled with two holes. A large central hole 12.5 mm diameter for a special immersion heater & a smaller hole, 7.5 mm diameter for a thermometer.

For determining the upper fixed point of thermometers & boiling points at barometer pressure other than atmospheric. Comprising an upper boiling vessel with a steam jacketed inner tube. A lid with a tubule is provided which holds the thermometer under test in a bung. A side outlet draining tube & a manometric tube mounted in a tubular with rubber bung; overall size 300 x 100 mm diameter. 

 A copper vessel having a cylindrical body & a conical top with a short neck for a bung. Fitted with a finger loop handle, steam outlet tube riffled for rubber tubing, & a glass water gauge tube. Type A) B) Capacity 1 litre 2 litres. 

For use at moderate pressures, made from glass tubing 6 mm bore, 8 mm outer diameter. The apparatus is open at both ends & is supplied unfilled. Dimensions 250 mm x 32 mm. 

With two plastic plates dia 30 cms, each carries aluminium foil segments. Maximum spark length 75 mm. The neutralising bars are provided. The collecting brushes are carried on a large insulating beam. A pair of high capacity lyden jars are incorporated which may be connected or disconnected as required. The complete apparatus is mounted on a wooden base with rubber feet. Overall dimensions: 450 x 175 x 500 mm. 

Comprises U & I cores of low loss magnetic material, to form a closed core of cross section 25 mm in plane of laminations, 32 mm perpendicular to them is an I – core of length 102 mm. U core external height 102mm. Internal height to take bobbin length 77 mm. Pair of pole pieces, each 65x30x25 mm with on end shaped to part of a cone for maximum flux density. Hole drilled through total length along cone axis to take a light beam. Pole pieces will accept supertrods & shading ring (provided with accessories) & may be clamped on any separation on U core, or in contact as a non laminated I – core. Cast aluminium alloy stand consisting of a heavy base on four rubber feet with removable clamping arms. Maximum dimensions of base 190x200x115 mm. Channel 35 mm wide & 3 mm deep to take transformer core, extends across full width. Integral support for arms, to rear, is below the level of the pole pieces. Arms pivot on steel spindle with adjustment of knobs to rear bringing hard rubber pads at front end of arms to bear on transformer core. Synthetic hammer finish except of clean metal in channel & 4 mm hole to take on earthing plug lead. Complete with all the accessories. 

Multiplate type, 2 volts 120 amps. Hard rubber container with plastic lid & screw terminals. Complete with instructions for charging. 

For use as series resistors or potentiometer. Slide wire type. Made of Brass/Aluminium with metal or bakelite feet. 

The heavy brass contact blocks are bound to the vulcanite plate by the double nut system. The plugs & lugs are cut to a fine taper & are interchangeable. The plug heads are machine moulded of bakelite. Each resistor independently mounted with double leads. Accuracy of constantan coils 0.1% for lower values & 0.5% for higher values. Fitted in polished wooden box.

Non inductively wound on plastic bobbin in transparent/opaque casing with two screw terminals adjusted to ±0.2% rating 1W.

1 Hz to 100 KHz:  Sine, square and triangular waveform short circuit protection. High input impedance amplifier. Output 0-20 volts pk-pk at 50 ohms.

A high power, robust, wide range signal generator providing sine, square and triangular waveforms. An instrument designed for a wide range of applications, with clear front panel layout for easy use. 

Technical Data

• Frequency range 1 Hz to 100 KHz in five decades and read on linearly calibrated scale.
• Accuracy ± 2% on all ranges. Output sine, square and triangular waveforms.
• Amplitude control continuously variable from zero to maximum output.
• Attenuator 0.2, 2, 20 Volts. Signal Generator and Amplifier:  A good quality high performance frequency generator with integral power amplifier. Output Frequency Range Output: 1 Hz to 110 KHz. 5 switched ranges. Sine, Triangular and Square waveforms.
• Outputs : High impedance with 600 ohms constant impedance attenuator.
• Low Impedance: Both outputs paired colour coded 4 mm sockets at 19 mm pitch. power 6 W rms into 8 ohms at low impedance output.
• Maximum Output: Voltage 14 volts pk-pk typical at high impedance output. Rise time of square wave 1 ?s (both outputs). All outputs are fully floating and short circuit proof.
• Input: Pair of colour coded 4 mm sockets and coaxial socket. Amplifier input impedance 1 Mohm.
• Attenuator: 0-20 dB with constant impedance at 600 ohms output.
• Controls: Mains switch on amplitude control.
• Frequency Control Dial: Range selection 5 positions switch. Attenuator three position switch.
• Electrical Protection: Internal 20 mm fuse.

Plated brass disc 22 mm diameter mounted on a metal shaft & fitted to a 6 mm insulating handle. Overall length 150 mm approx. 

Mac-Cartney Bottles, "GWL", Complete with Aluminium Cap.

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Dropping Bottles, "GWL", fitted with interchangeable stopper and rubber teat.

For demonstrating the differential expansion of two different metals. One each brass & iron plates 350 x 35 mm riveted together from end to end with wooden handle. 

Reagent Bottles, "GWL", Wide Mouth, with interchangeable hollow Stopper.

RECTANGULAR Sizes:

• 75 x 50 x 12 mm
• 75 x 50 x 18 mm
• 100 x 60 x 18 mm
• 115 x 65 x 18 mm
• 125 x 65 x 18 mm

Semi Circular Sizes:

• 100 x 18 mm
• 100 x 12 mm

A simple demonstration of a Dynamo Model mounted on a wooden base of size 200 x 170 mm. Hand driven by a gear. Simplified open frame construction which can be readily understood without detriments to its essential similarity to real machine. A 2 pole armature wound by enameled copper wire to rotate in U shape magnet in pivot. While in rotation process through the gear wheel by hand, the bulb provided glows. 

The metal box is double ended so that two sets of students can work independently with the same box. Slide apertures are provided which accommodate colour filters for colour mixing experiments & have blinking plates for when the slide apertures are not in use. The box is provided with a 12V 24W straight filament lamp fixed at the centre of the apparatus while at each end is a sliding grooved frame to carry a convex cylindrical lens together with slit screen &/or filter. Long clear tracks. To triple slit screen, two blank plates for closing side aperture when not in use & 1m of twin flex. Dimensions 308 x 63 x 115 mm high supplied without lenses, filters or other accessories. 

Four each of copper & iron wires 125 mm long joined together from 7 points; four on one side & three on the other. With brass connections on the outer wires. 

Student Spectrometer: The base, integral with the collimator tube support, carries the swinging telescope arm pivoted on a bearing with spring loaded end thrust plates. This type of bearing eliminates any slack which would otherwise develop with wear. The collimator & telescope tubes are one piece precision casting in light alloy, concealed helical action focusing devices are provided. The collimator slit with spring loaded jaws is of a new & robust design which ensures retention of the initial accuracy. The graduated prism table support, 180 mm diameter, is divided in degrees; the vernier, reading to 0.1, is fixed to the telescope arm. This arrangement permits easy estimation to 0.05 from the conveniently positioned vernier scale. The fully adjustable prism table 75 mm diameter is engraved with concentric rings, which facilitates correct location of a prism & has two screwed holes for the attachment of the prism & grating holder, to accommodate a prism upto 25 mm high. Large diameter clamping knob are fitted for movement control & fine adjustment is provided for the telescope. All bright parts are chromium plated with the base & tube in synthetic hammer finish. Overall dimensions 510 x 230 x 220 mm without prism. 

Intermediate Spectrometer: Comprises of the following items : 

• Spectrometer: Telescope vernier reads to 1 min. of arc. A model for student use, with an optical system equivalent to that on more advanced models, thus permitting many quantitative experiments. Graduated disc 127 mm diameter, fixed to table, double ended vernier, to read to one min. of arc, attached to telescope. Both telescope & table have fine adjustment screws & release of clamping screw enables coarse adjustments to be made by hand. Telescope & collimator are fitted with 178 mm focal length, 32 mm clear aperture achromatic objectives & have rack & pinion focusing telescope fitted with 15x Ramsden eye piece & crossline graticule, collimator with adjustable slit, length 6 mm, mounting on telescope & collimator permits accurate levelling of axis & squaring of axis of rotation. The spectrometer table, marked with lines to assist positioning of prism & diffraction grating. Complete in hard wood case with following accessories: One prism clamp, one diffraction grating holder, one watchmakers’ eyeglass, one tommy bar for adjusting optical axis. 
• Mercury Vapour Lamp: With holder & choke 80W & 120W. 
• Sodium Vapour Lamp: 45 Watt, 220 Volts 
• Lamphouse & Transformer: Comprising a lamphouse & transformer. The lamp gives a steady light for high intensity. Special design of transformer ensures that the lamp starts immediately as it is switched on. When mounted on the integral stand, the lamp is enclosed by a cylindrical lamp house with a circular aperture & the light centre height is adjustable from 200 mm onwards. The lamp house is open at the top to allow for ventilation & may be removed for operation on a separate stand, as required. The transformer is housed in a two part sheet steel case with ventilation louvres & has a lamp house supplying rod mounted directly onto the transformer case provide a convenient self contained assembly. A 3 core captive flying lead is provided for mains connection. 

Polypropylene body, unbreakable, non corrosive white and has a spout to drain out overflowing liquid, used in a laboratory for measuring displacement of liquids.

TIN/BRASS: With overflow spout for specific gravity experiments; size of vessel 115 x 50 mm approx. 

LARGE: Hammertone coloured tinplate; with handle and over flow spout; size of vessel 225 x 125 mm approx.

Useful as basic component for any electrical laboratory.Mounted on bakelite base. Allows visible connection for easy use. With screw holes and suitable for bench fixing and panel mounting. Available in four configurations.

Type;-   

• Single – Pole, Single – Throw   
• Single – Pole, Double – Throw   
• Double– Pole, Single – Throw   
• Double – Pole, Double – Throw 

Enclosed in a borosilicate glass tube 33 cms long, 14 mm dia. Four terminals (2 mains, 2 compensatory) resistance approx. 2.8 ohms. Fundamental interval 1 ohm. Range 0 – 500º C 

Designed for use specifically with the tutor kit units, but equally suitable for general purpose use, this unit provides a fixed output of 5 V D.C. at 1 A for TTL logic circuits and adjustable outputs at 15 V at 100 mA for op-amp and other linear applications. 

Grease spot disc held between two wooden screens with 45 mm dia aperture, mounted with 2 inclined plane mirrors approx. 90 mm square.

Pin Hole Camera

Two rectangular, open ended, light proof wood boxes. One slides into the other & contains a frosted translucent glass plate upon which image is formed. The other box has a pin hole opening at the closed end. Dimensions 150 x 100 x 100 mm approx. Also available as a kit.

For demonstrating the effect of electric discharge from points. The apparatus has 60 mm diameter six pointed star wheel with all the points curved in one direction. The wheel rotates freely on a pivot point mounted on a short stand & the stand is provided with a 4 mm connection socket on the round base. 

Half Meter Bridge: Four-Gap bridges – 0.5 and 1 m Two and four wire potentiometers – 2m Dual figured scale   

Four gap type, mounted on rigid PVC/Wooden base. With Constantan wire 0.56 mm dia. and plated copper strips and connecting pieces. Fitted with 4 mm socket terminals and scale graduated 0 to 50 cm x 1 mm and 50 to 0 cm x 1 mm. Complete with Pencil Jockey 

Optical Bench 1 Meter, Wooden: Comprising a wooden base board 1100mm x 115 mm with one meter scale divided in mm & figured at every cm fixed along the front edge & complete with following accessories: Two white faced object & receiving screen, one plane mirror 150 x 100 mm, 4 lens holder V shaped, one needle mounted vertically in a short wooden rod in the centre of a wooden base. The optical centre height of all the components is 100 mm above the baseboard.

Optical Bench 1.5 Meters: Comprising a wooden base board 1600mm x 140 mm with a 1.5 meter scale divided in mm plus six sliding moulded metallic bases 100 x 50 mm each with engraved line, brass pillar with screw for locking. Accessories: one 240V white lamp with lamp house; 1 metal object white screen 75mm diameter with gauze; 1 metal object white receiving screen 100 x 75 mm; 1 needle mounted in rod 6 mm; 1 plane mirror 100 x 75 mm. All the accessories mounted on a 6mm brass rod which fits in a stand giving an optical height of approx. 125 mm above the base board.

Optical Bench 1 Meter: One meter long, for advanced research work; consists of two rods, one stainless steel & one chrome plated steel. The stainless rod is divided in mm. These are supported on heavy cast iron feet with leveling screws. Four specially designed metal sliders having a fine index mark enables reading to be taken on scale with ease & accuracy. The sliders are machined metal so they slide accurately & smoothly on the bed. Two of the sliders have transverse slow motion adjustment. Complete with 6 accessories ( 2 lens holders, 2 optical pins, 1 candle holder, & 1 screen ground glass).

Optical Bench, 1.5 Meters: Same as Optical Bench 1 Meter but 1.5 meters long. 

For Wheatstone Bridge & Potentiometers. Metal knife edge mounted in plastic handle, 90 mm long x 12 mm dia with terminal at the upper end. 

Potentiometer – 1 Wire: Slide wire pattern with one wire, 1 meter long, mounted on a polished wooden base with boxwood rule graduated 0 – 100 cm x 1 cm with three socket type 4 mm terminals to enable the apparatus to be used either as a one meter or two meter instrument with sliding jockey. 

Potentiometer – 4 wire: Same as Wire1 with 4 wires of 24 SWG Constantan connected in series to give effective length of 4 meters; with two terminals. With jockey having knife edge press keys type giving accurate contacts & a terminal for connection.

Bottles Aspirator, "GWL", with Screw Cap, Glass key stopcock with interchangeable joint.

Lids For Reaction Flasks, "GWL", Flat flange 100 mm. I.D., 150 mm. O.D., with multiple Sockets.

Specific Gravity Bottles, "GWL", Class A with Ground in thermometer range 0 to 50°C, with works Certificate. (Pyknometer)

Reagent Bottle “GWL” Clear, wide mouth with Polypropylene Blue screw cap and pouring ring, repeatedly autoclaveable, Graduated.

Two rectangular, open ended, light proof wood boxes. One slides into the other & contains a frosted translucent glass plate upon which image is formed. The other box has a pin hole opening at the closed end. Dimensions 150 x 100 x 100 mm approx. Also available as a kit. 

A bakelite ring or bobbin is of 165 mm diameter with 3 windings of 2, 50, & 500 turns. The magnetometer is supported on a brass tube fitted on an ebonite plate which is free to revolve in the base of the instrument. The magnetometer & the ring can both be rotated independently of the base which is with levelling screws. The compass box consists of a bakelite base with metal dial of diameter 100 mm graduated in degrees & with anti parallax mirror. Cobalt steel magnet & aluminium pointer are mounted on special synthetic sapphire. The needle moves on special pivot. This combination makes the needle virtually frictionless. 

GWL- A

Solenoid (Helix), Iron Core: For studying magnetic induction properties produced by electric current and the effect of an iron core. Consists of plastic spool with windings of enameled copper wire having brass binding posts on square end supports. Includes a soft iron core rod of diameter 18 cm.

GWL- B

Solenoid (Helix) Air Core: To provide external magnetic field where required and to change the rate of magnetic flux passing through a coil.

Consists of a plastic spool with windings of insulated copper. End plates have brass bindings posts. Capacity 10 amperes when used intermittently and 5 amperes when used continuously.

GWL- A

Induction Coil: The primaries are wound with thicker copper enamelled covered wire on letherite pipe in two layers. The secondary coils are divided into two parts & are given heavy insulation. Each layer is wound in a cover of butter paper & are completing the winding, the entire is dipped into hot wax to seal each layer against moisture effect. The coils are housed in a teakwood base, voltage tested condensers are fitted inside the wooden polished base. Handles to get the spark are fitted on it & make or break points are of silver. One point is adjustable to get any cycle. On/off reversing switch commutator working on 6 to 12 V DC.

GWL- B

Dissectible Induction Coil: Most suitable for demonstration. Secondary coil & capacitor can be easily separated out. With arrangements for disconnecting & capacitor, while in operation. All connections clearly visible. Spark length 25 mm. 

Telescope Model, Astronomical: Comprising a convex lens 38 mm diameter & 150 mm focal length, mounted in a plastic tube 400 x 50 mm diameter, & a double convex lens 50 mm diameter & 500mm focal length, mounted in a tube 400 x 55 mm diameter. The smaller tube is located in the large tube my means of foam plastic rings which provide an effective sliding light seal. 

Telescope Model, Terrestrial: Same as 108.39 but with plano concave eye piece lens to provide erect image. 

Astronomical Telescope: Reflecting type, fitted with about 45 mm dia achromatic objective having focal length of about 450 mm. Focusing is provided by rack & pinion. Complete with carrying case with the metallic three legged folding type tripod stand. 

Reading Telescope: Designed for general laboratory work. The telescope is mounted on 18 mm diameter, pillar 450 mm long fitted on a heavy tripod base. The telescope can be rotated both in vertical as well as horizontal plane. It is fitted with 180 mm focus achromatic object with 25 mm clear aperture , 10x ramsden eye piece with cross wire. The telescope is focused by rack & pinion & has a range from one meter to infinity; with perspex scale & its attachment. 

Reflecting Telescope: A high quality instrument with a resolving power of 1.5 seconds. The 100 mm (4 inch) diameter, 1000 mm focal length mirror gives relatively more light & less chromatic aberration than an equivalent refractor. Magnifications of upto 250x are obtainable. The telescope has an equatorial mount with hour and declination circle & micro adjustments with flexible connections to avoid vibrations. The whole is mounted on a heavy 1.52 m tripod with an accessory tray. Supplied complete with two interchangeable eye lenses 6 mm & 20 mm, a 2x Barlow lens, sun filter, moon filter, a 5×24 star finder telescope (with mount on main telescope body), a solar aperture cap & an instruction booklet with space & moon maps.

Kit consists of two lamp holders, each in metal shade with two axial slots & mounted on metal support rod. Holder complete with approx. 1.2m 2 wire P.V.C. covered cable & 12V 24W axial filament lamp. One each right & left hand cylindrical lamp shields, in matt black ‘combs’; with 17 equispaced parallel slots, Two black plastic plates, each with single & triple slits, two comb & plate holders, a spring loaded clip mounted on metal support bracket, 4 metal light barriers, 4 each plano convex cylindrical lenses, 50 x 50 mm, +7D, two each cylindrical lenses 50 x 50 mm respectively, plano convex +10D, +17D, plano concave -17D. 

To demonstrate unequal expansion. Metals of different expansion coefficients Are rolled in form of a strip. 

Calorimeters Copper/ Aluminium: One piece spinning with parallel sides & rolled rim. Type A) B) Size 75 x 50 mm 100 x 75 mm Available in both Copper & Aluminium.

Calorimeter Set: A complete set comprising the following : 1 copper calorimeter 75 x 50 mm 1 wooden outer box with felt lining 100 x 75 mm approx. 1 sliding wooden cover for outer box 1 copper stirrer with loop to fit inside the copper calorimeter 1 thermometer holder made of brass, removable

Calorimeter Set Copper: Consisting of spun copper cylinder contained within a large 75 mm diameter x 100 mm aluminium outer vessel with 10 mm of insulating material between. Supplied with wooden cover for outer vessel with bung for mounting thermometer support clip. Dimensions: 110 mm x 200 mm overall.

Joule’s Calorimeter: For determining the specific heat capacity of liquid by electrical method. Consisting of a nickel plated copper vessel 75 x 50 mm size with outer vessel of teak wood fitted with bakelite top with hole for thermometer. The terminals connected to a coil of wire (for current up to 3 amps.) are fitted, complete with stirrer & outer teakwood vessel.

Metal Block Calorimeters : For experimental determination of the specific heat capacity of different metals. Cylindrical metal blocks of mass 1 kg; adjusted to accuracy of ±2%. Each block drilled with two holes. A large central hole 12.5 mm diameter for a special immersion heater & a smaller hole, 7.5 mm diameter for a thermometer.

For determining the upper fixed point of thermometers & boiling points at barometer pressure other than atmospheric. Comprising an upper boiling vessel with a steam jacketed inner tube. A lid with a tubule is provided which holds the thermometer under test in a bung. A side outlet draining tube & a manometric tube mounted in a tubular with rubber bung; overall size 300 x 100 mm diameter. 

 A copper vessel having a cylindrical body & a conical top with a short neck for a bung. Fitted with a finger loop handle, steam outlet tube riffled for rubber tubing, & a glass water gauge tube. Type A) B) Capacity 1 litre 2 litres. 

For use at moderate pressures, made from glass tubing 6 mm bore, 8 mm outer diameter. The apparatus is open at both ends & is supplied unfilled. Dimensions 250 mm x 32 mm. 

With two plastic plates dia 30 cms, each carries aluminium foil segments. Maximum spark length 75 mm. The neutralising bars are provided. The collecting brushes are carried on a large insulating beam. A pair of high capacity lyden jars are incorporated which may be connected or disconnected as required. The complete apparatus is mounted on a wooden base with rubber feet. Overall dimensions: 450 x 175 x 500 mm. 

Comprises U & I cores of low loss magnetic material, to form a closed core of cross section 25 mm in plane of laminations, 32 mm perpendicular to them is an I – core of length 102 mm. U core external height 102mm. Internal height to take bobbin length 77 mm. Pair of pole pieces, each 65x30x25 mm with on end shaped to part of a cone for maximum flux density. Hole drilled through total length along cone axis to take a light beam. Pole pieces will accept supertrods & shading ring (provided with accessories) & may be clamped on any separation on U core, or in contact as a non laminated I – core. Cast aluminium alloy stand consisting of a heavy base on four rubber feet with removable clamping arms. Maximum dimensions of base 190x200x115 mm. Channel 35 mm wide & 3 mm deep to take transformer core, extends across full width. Integral support for arms, to rear, is below the level of the pole pieces. Arms pivot on steel spindle with adjustment of knobs to rear bringing hard rubber pads at front end of arms to bear on transformer core. Synthetic hammer finish except of clean metal in channel & 4 mm hole to take on earthing plug lead. Complete with all the accessories. 

Multiplate type, 2 volts 120 amps. Hard rubber container with plastic lid & screw terminals. Complete with instructions for charging. 

For use as series resistors or potentiometer. Slide wire type. Made of Brass/Aluminium with metal or bakelite feet. 

The heavy brass contact blocks are bound to the vulcanite plate by the double nut system. The plugs & lugs are cut to a fine taper & are interchangeable. The plug heads are machine moulded of bakelite. Each resistor independently mounted with double leads. Accuracy of constantan coils 0.1% for lower values & 0.5% for higher values. Fitted in polished wooden box.

Non inductively wound on plastic bobbin in transparent/opaque casing with two screw terminals adjusted to ±0.2% rating 1W.

1 Hz to 100 KHz:  Sine, square and triangular waveform short circuit protection. High input impedance amplifier. Output 0-20 volts pk-pk at 50 ohms.

A high power, robust, wide range signal generator providing sine, square and triangular waveforms. An instrument designed for a wide range of applications, with clear front panel layout for easy use. 

Technical Data

• Frequency range 1 Hz to 100 KHz in five decades and read on linearly calibrated scale.
• Accuracy ± 2% on all ranges. Output sine, square and triangular waveforms.
• Amplitude control continuously variable from zero to maximum output.
• Attenuator 0.2, 2, 20 Volts. Signal Generator and Amplifier:  A good quality high performance frequency generator with integral power amplifier. Output Frequency Range Output: 1 Hz to 110 KHz. 5 switched ranges. Sine, Triangular and Square waveforms.
• Outputs : High impedance with 600 ohms constant impedance attenuator.
• Low Impedance: Both outputs paired colour coded 4 mm sockets at 19 mm pitch. power 6 W rms into 8 ohms at low impedance output.
• Maximum Output: Voltage 14 volts pk-pk typical at high impedance output. Rise time of square wave 1 ?s (both outputs). All outputs are fully floating and short circuit proof.
• Input: Pair of colour coded 4 mm sockets and coaxial socket. Amplifier input impedance 1 Mohm.
• Attenuator: 0-20 dB with constant impedance at 600 ohms output.
• Controls: Mains switch on amplitude control.
• Frequency Control Dial: Range selection 5 positions switch. Attenuator three position switch.
• Electrical Protection: Internal 20 mm fuse.

Plated brass disc 22 mm diameter mounted on a metal shaft & fitted to a 6 mm insulating handle. Overall length 150 mm approx. 

Mac-Cartney Bottles, "GWL", Complete with Aluminium Cap.

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Dropping Bottles, "GWL", fitted with interchangeable stopper and rubber teat.

For demonstrating the differential expansion of two different metals. One each brass & iron plates 350 x 35 mm riveted together from end to end with wooden handle. 

Reagent Bottles, "GWL", Wide Mouth, with interchangeable hollow Stopper.

RECTANGULAR Sizes:

• 75 x 50 x 12 mm
• 75 x 50 x 18 mm
• 100 x 60 x 18 mm
• 115 x 65 x 18 mm
• 125 x 65 x 18 mm

Semi Circular Sizes:

• 100 x 18 mm
• 100 x 12 mm

A simple demonstration of a Dynamo Model mounted on a wooden base of size 200 x 170 mm. Hand driven by a gear. Simplified open frame construction which can be readily understood without detriments to its essential similarity to real machine. A 2 pole armature wound by enameled copper wire to rotate in U shape magnet in pivot. While in rotation process through the gear wheel by hand, the bulb provided glows. 

The metal box is double ended so that two sets of students can work independently with the same box. Slide apertures are provided which accommodate colour filters for colour mixing experiments & have blinking plates for when the slide apertures are not in use. The box is provided with a 12V 24W straight filament lamp fixed at the centre of the apparatus while at each end is a sliding grooved frame to carry a convex cylindrical lens together with slit screen &/or filter. Long clear tracks. To triple slit screen, two blank plates for closing side aperture when not in use & 1m of twin flex. Dimensions 308 x 63 x 115 mm high supplied without lenses, filters or other accessories. 

Four each of copper & iron wires 125 mm long joined together from 7 points; four on one side & three on the other. With brass connections on the outer wires. 

Student Spectrometer: The base, integral with the collimator tube support, carries the swinging telescope arm pivoted on a bearing with spring loaded end thrust plates. This type of bearing eliminates any slack which would otherwise develop with wear. The collimator & telescope tubes are one piece precision casting in light alloy, concealed helical action focusing devices are provided. The collimator slit with spring loaded jaws is of a new & robust design which ensures retention of the initial accuracy. The graduated prism table support, 180 mm diameter, is divided in degrees; the vernier, reading to 0.1, is fixed to the telescope arm. This arrangement permits easy estimation to 0.05 from the conveniently positioned vernier scale. The fully adjustable prism table 75 mm diameter is engraved with concentric rings, which facilitates correct location of a prism & has two screwed holes for the attachment of the prism & grating holder, to accommodate a prism upto 25 mm high. Large diameter clamping knob are fitted for movement control & fine adjustment is provided for the telescope. All bright parts are chromium plated with the base & tube in synthetic hammer finish. Overall dimensions 510 x 230 x 220 mm without prism. 

Intermediate Spectrometer: Comprises of the following items : 

• Spectrometer: Telescope vernier reads to 1 min. of arc. A model for student use, with an optical system equivalent to that on more advanced models, thus permitting many quantitative experiments. Graduated disc 127 mm diameter, fixed to table, double ended vernier, to read to one min. of arc, attached to telescope. Both telescope & table have fine adjustment screws & release of clamping screw enables coarse adjustments to be made by hand. Telescope & collimator are fitted with 178 mm focal length, 32 mm clear aperture achromatic objectives & have rack & pinion focusing telescope fitted with 15x Ramsden eye piece & crossline graticule, collimator with adjustable slit, length 6 mm, mounting on telescope & collimator permits accurate levelling of axis & squaring of axis of rotation. The spectrometer table, marked with lines to assist positioning of prism & diffraction grating. Complete in hard wood case with following accessories: One prism clamp, one diffraction grating holder, one watchmakers’ eyeglass, one tommy bar for adjusting optical axis. 
• Mercury Vapour Lamp: With holder & choke 80W & 120W. 
• Sodium Vapour Lamp: 45 Watt, 220 Volts 
• Lamphouse & Transformer: Comprising a lamphouse & transformer. The lamp gives a steady light for high intensity. Special design of transformer ensures that the lamp starts immediately as it is switched on. When mounted on the integral stand, the lamp is enclosed by a cylindrical lamp house with a circular aperture & the light centre height is adjustable from 200 mm onwards. The lamp house is open at the top to allow for ventilation & may be removed for operation on a separate stand, as required. The transformer is housed in a two part sheet steel case with ventilation louvres & has a lamp house supplying rod mounted directly onto the transformer case provide a convenient self contained assembly. A 3 core captive flying lead is provided for mains connection. 

Polypropylene body, unbreakable, non corrosive white and has a spout to drain out overflowing liquid, used in a laboratory for measuring displacement of liquids.

TIN/BRASS: With overflow spout for specific gravity experiments; size of vessel 115 x 50 mm approx. 

LARGE: Hammertone coloured tinplate; with handle and over flow spout; size of vessel 225 x 125 mm approx.

Useful as basic component for any electrical laboratory.Mounted on bakelite base. Allows visible connection for easy use. With screw holes and suitable for bench fixing and panel mounting. Available in four configurations.

Type;-   

• Single – Pole, Single – Throw   
• Single – Pole, Double – Throw   
• Double– Pole, Single – Throw   
• Double – Pole, Double – Throw 

Enclosed in a borosilicate glass tube 33 cms long, 14 mm dia. Four terminals (2 mains, 2 compensatory) resistance approx. 2.8 ohms. Fundamental interval 1 ohm. Range 0 – 500º C 

Designed for use specifically with the tutor kit units, but equally suitable for general purpose use, this unit provides a fixed output of 5 V D.C. at 1 A for TTL logic circuits and adjustable outputs at 15 V at 100 mA for op-amp and other linear applications. 

Grease spot disc held between two wooden screens with 45 mm dia aperture, mounted with 2 inclined plane mirrors approx. 90 mm square.

Pin Hole Camera

Two rectangular, open ended, light proof wood boxes. One slides into the other & contains a frosted translucent glass plate upon which image is formed. The other box has a pin hole opening at the closed end. Dimensions 150 x 100 x 100 mm approx. Also available as a kit.

For demonstrating the effect of electric discharge from points. The apparatus has 60 mm diameter six pointed star wheel with all the points curved in one direction. The wheel rotates freely on a pivot point mounted on a short stand & the stand is provided with a 4 mm connection socket on the round base. 

Half Meter Bridge: Four-Gap bridges – 0.5 and 1 m Two and four wire potentiometers – 2m Dual figured scale   

Four gap type, mounted on rigid PVC/Wooden base. With Constantan wire 0.56 mm dia. and plated copper strips and connecting pieces. Fitted with 4 mm socket terminals and scale graduated 0 to 50 cm x 1 mm and 50 to 0 cm x 1 mm. Complete with Pencil Jockey 

Optical Bench 1 Meter, Wooden: Comprising a wooden base board 1100mm x 115 mm with one meter scale divided in mm & figured at every cm fixed along the front edge & complete with following accessories: Two white faced object & receiving screen, one plane mirror 150 x 100 mm, 4 lens holder V shaped, one needle mounted vertically in a short wooden rod in the centre of a wooden base. The optical centre height of all the components is 100 mm above the baseboard.

Optical Bench 1.5 Meters: Comprising a wooden base board 1600mm x 140 mm with a 1.5 meter scale divided in mm plus six sliding moulded metallic bases 100 x 50 mm each with engraved line, brass pillar with screw for locking. Accessories: one 240V white lamp with lamp house; 1 metal object white screen 75mm diameter with gauze; 1 metal object white receiving screen 100 x 75 mm; 1 needle mounted in rod 6 mm; 1 plane mirror 100 x 75 mm. All the accessories mounted on a 6mm brass rod which fits in a stand giving an optical height of approx. 125 mm above the base board.

Optical Bench 1 Meter: One meter long, for advanced research work; consists of two rods, one stainless steel & one chrome plated steel. The stainless rod is divided in mm. These are supported on heavy cast iron feet with leveling screws. Four specially designed metal sliders having a fine index mark enables reading to be taken on scale with ease & accuracy. The sliders are machined metal so they slide accurately & smoothly on the bed. Two of the sliders have transverse slow motion adjustment. Complete with 6 accessories ( 2 lens holders, 2 optical pins, 1 candle holder, & 1 screen ground glass).

Optical Bench, 1.5 Meters: Same as Optical Bench 1 Meter but 1.5 meters long. 

For Wheatstone Bridge & Potentiometers. Metal knife edge mounted in plastic handle, 90 mm long x 12 mm dia with terminal at the upper end. 

Potentiometer – 1 Wire: Slide wire pattern with one wire, 1 meter long, mounted on a polished wooden base with boxwood rule graduated 0 – 100 cm x 1 cm with three socket type 4 mm terminals to enable the apparatus to be used either as a one meter or two meter instrument with sliding jockey. 

Potentiometer – 4 wire: Same as Wire1 with 4 wires of 24 SWG Constantan connected in series to give effective length of 4 meters; with two terminals. With jockey having knife edge press keys type giving accurate contacts & a terminal for connection.

Bottles Aspirator, "GWL", with Screw Cap, Glass key stopcock with interchangeable joint.

Lids For Reaction Flasks, "GWL", Flat flange 100 mm. I.D., 150 mm. O.D., with multiple Sockets.

Specific Gravity Bottles, "GWL", Class A with Ground in thermometer range 0 to 50°C, with works Certificate. (Pyknometer)

Reagent Bottle “GWL” Clear, wide mouth with Polypropylene Blue screw cap and pouring ring, repeatedly autoclaveable, Graduated.

Two rectangular, open ended, light proof wood boxes. One slides into the other & contains a frosted translucent glass plate upon which image is formed. The other box has a pin hole opening at the closed end. Dimensions 150 x 100 x 100 mm approx. Also available as a kit.