Edward Craven Walker & Crestworth Ltd Patents
1. Mr Edward Craven Walker's Life. A short Biography of an amazing inventor.


Edward Craven Walker was born in Singapore in 1918, where his father was a port agent for P&O. He was educated at Charterhouse, and in the Thirties worked for British American Tobacco at their huge cigarette factory in Millbrook, Southampton. There he met Pearl Corney, with whom he fell in love, only to be parted from her when he was posted to India. But the Second World War broke out on the day he was due to sail, and instead he joined the RAF, becoming a squadron leader and flying "blind" missions in Mosquitoes on photographic reconnaissance.

Back in civilian life, Walker and an RAF friend, Simon Templar, set up an international home-exchange agency, "En Famille", arranging for families to swap their homes for holidays abroad. The venture accorded with an optimistic post-war spirit: "It was good fun", said Walker, "and it encouraged international friendship." It also seemed to lead naturally, as it were, to his next great enthusiasm: naturism.

On a visit to the Ile du Levant, off the south coast of France, Walker was inspired by the naturist movement. As part of his mission, he turned his hand to film production, directing Eves on Skis (1958) - Austrian madchen on the piste - and Travelling Light (1960).

The first naturist film to be passed by the British Board of Film Classification, it ran for many months in the West End and was distributed world-wide, albeit to audiences who did not always have a serious interest in the healthy benefits of the naturist cause. "I didn't make it to make money," said Walker, "although it did make me very rich. I made it as propaganda for the naturist way of life."

In the mid-1950s, Walker and a friend chanced upon a bizarre contraption on the bar of the Queen's Head near Ringwood, Hampshire. A novelty egg- timer dating from the Second World War, it had been filled with odd oily globules - when the wax melted and rose to the top of the glass, your egg was ready.

Edward Craven Walker (1918 –- August 15, 2000), born in Singapore, is mainly remembered as being the inventor of the psychedelic ‘Astro’ Lamp, or ‘Lava Lamp’ as it is known in America.

Craven Walker was also an accomplished pilot and during WWII flew a DeHavilland Mosquito over Germany taking photographs of enemy positions. Despite the distinct danger of flying deep into enemy territory with no lights and armed only with a 3D camera, he successfully made it through the war. He met his first wife, Marjorie Bevan Jones, during WWII at one of the Air Force bases where she was serving with the WAAF. Craven Walker continued flying fixed wing aircraft right the way through his life.

After the end of the war Craven Walker set about developing an idea he had thought in a country pub. The pub had on display a contraption that fascinated Craven and he vowed to expand on the concept. It had been made by one of the pubs old regulars Mr Dunnet who had since departed and was a one-off homemade device consisting of an egg-timer and a lightbulb. While the device itself was fairly rudimentary, Craven saw its potential and set about perfecting it. Above on the right is the original Crestworth factory on the right of the image.

Edward Craven Walker attended Charterhouse school from the age of 13. He joined the school at the beginning of the Oration Quarter (Autumn Term) 1931 and left at the end of the Summer Term 1935. He was in Pageites bording house. He became a prefect in his final term and he had reached the Special Science Vth From by the time he had left. He played football for the house team and for the Swallows house club side. In the 1934/5 season he scored two goals for Pageites in their win against Lockites, but unfortunately there was no report of their next round match.

He was playing Fives for the school in 1934, while still under 16 he helped Pageites to win the Under XVI house fives final. He recieved his Fives colours in 1934. He also captained the team in 1935, when Pageites won the house competition. He also played cricket for the school Maniacs team. He took part in the 1935 production of The Masque of Charterhouse, which was a pageant of scenes from the history of the school, first created for the school's tercentenary in 1911.

2. Crestworth Ltd. Vintage Patents.

To download patent information, click on an image of interest below. Adobe Acrobat/ Preview is required to open .pdf files.


Over a period of time, Walker developed a lamp which was based on the egg timer invention, it was a stunning invention that has withstood the test of time. It was marketed as the Astro Lamp and was produced in Poole. There were different variations of the Astro. Selfridges stocked the first lamps, which hit the market at just the right time, appealing to swinging young customers in a new consumer age. "If you buy my lamp, you won't need drugs," said its inventor. At the peak of its success, his Poole-based factory was selling seven million lamps a year.

But, as popular culture recycled itself, the lava lamp's time came back. Cressida Granger had been buying the lamps for her Camden market stall and with a business partner, David Mulley, rebranded Crestworth to Mathmos, with Walker as consultant. They continued production in Poole, capitalising on nostalgia for the Sixties and Seventies and had great success. Mathmos now produces a wide array of kinetic ambient lighting.

Below are some of the very first Crestworth Patents:

Above: Patent Specification: Inventor:- David George Smith (Crestworth Limited of 59 Kennington Road, London, S.E.1).

Above: Date of Filing Complete Specification: Feb.19, 1965.

Above: Application Date: March 18, 1964. No. 11555/64

We have just recieved word from an ex-Crestworth employee who was employed at Kennington Road. This was the very first Crestworth address, and the whole concept evolved from this address. The small offices at 59 Kennington Road featured the people who were responsible for the launch of the Astro lamp, the world's very first lava lamp.

Above: United States Patent: DISPLAY DEVICES

David George Smith, London, England, assignor to Crestworth Limited, London, England.

Filed Mar.4, 1965.

Above: USA Patent Office> DISPLAY DEVICE. Edward C. Walker, Woodspeen, Forest Corner.

Ringwood, Hampshire, England. Filed Nov. 13, 1963.

The lamps were a massive success through the 60's, becoming symbolic of psychedelia, and virtually every household had one. Craven Walker said of its mesmerizing motions, "If you buy my lamp, you won't need drugs... I think it will always be popular. It's like the cycle of life. It grows, breaks up, falls down and then starts all over again". Through the high-flying 80's the ‘Astro’ lamp was considered extremely unfashionable and Crestworth pretty much closed down. However, in the early 90's, a young couple once again saw the potential of the lamps and began manufacturing and selling them successfully. Cressida Granger and David Mulley approached Craven Walker after becoming interested in the Astro’s popularity at Camden Market. Craven Walker offered them a deal penned on a piece of A4 paper. They would take on 20% ownership of Crestworth and run the company for a year and if they could make it profitable, they would be given 80%. It was a great opportunity so they worked extremely hard and were successful in their mission. They changed the company name from Crestworth to Mathmos in 1992 but continue to manufacture the lamps from the original factory in Poole, Dorset to this very day. Mr. Walker remained a minority shareholder in the company for five years and then remained a consultant at Mathmos until he passed away.

Toward the end of the decade Craven Walker had began to get ill. Over the next few years he battled with Cancer, defeating it once only for it to reappear. He died in August 15 2000 at Matchams in Ringwood, Hampshire from Cancer and was buried in a small cemetery in the New Forest. He was 82.
Edward Craven Walker was not just responsible for the ‘Astro’ Lamp. He was one of the first dedicated Naturists, setting up his own camp at Matchams in Hampshire. The club thrived and became one of the largest of its kind in the UK. He was also extremely interested in film and he combined this with his love of naturism. In the 50's and 60's nudity on film was very taboo and virtually unheard of but he managed to evade the censors by not showing any pubic hair. As a result he became a pioneer in this early genre of film. Under the pseudonym Michael Keatering, Craven Walker directed the landmark naturist film Travelling Light (also known as Traveling Light (1959)). This was the first naturist film to receive public release in the UK. Described as an underwater ballet, this film was shot off Corsica and was released in 1960.
It is a tribute to him that his invention has stood the test of time & continues to touch the hearts of many people. He will be sadly missed.

3. Queen's Head Pub.

Mr Walker saw the foundation of the idea of the lava lamp from a contraption at a country pub in the New Forest in England. This pub named: Queen's Head still exists today. Queen's Head. The Cross, Burley, Ringwood, Hampshire BH24 4AB


4. Early Astro 1960's Instructions...

Original Documentation of Crestworth Astro Typed Below.
These instructions come from an Early Astro and has an early address which is rare to see referred to: Crestworth Ltd. West Quay Road. Poole Dorset.
Unlike later which have the Sterte Avenue Address.

"Solid" Lamp Vast Improvement on Old "Liquid" Lamp.

The "Astro" Lamp is made in a wide range of different pairs of contrasting colours, designed to compliment your home. All its components are made by craftsmen, the base and lamp-house behind hand-spun and the vase being of best quality glass. The special chemical components comprising each of the two non-miscible liquids have to added in minutely accurate proportions in order to create the singularly fascinating effect. At one time, both of these components remained liquid at all temperatures, but this led to the danger of emulsification if the lamp was shaken. In order to counteract this and, at the same time, to facilitate handling, distribution and refilling, the lower (moving) liquid is now made to solidify when the lamp is cold.
The following notes are given in order to ensure that the "Astro" Lamp will give the maximum pleasure, beauty and satisfaction that it is capable of bringing to your home.

>Room Temperature.
An "Astro" Lamp uses heat as well as light. The "Solid" will melt and start to move only when it has been gently heated up to about blood temperature (about 37 degrees Centigrade or 98 degrees Fahrenheit) by the electric bulb supplied in the base. The lamp should never been heated up by any other means, nor should it be cooled down artificially, as any sudden change in temperature could crack the glass or adversely affect the action. On no account should the Lamp be used if the vase is cracked or damaged in any way.

It has been designed to operate best in an average room temperature (about 15 degrees to 20 degrees). In such conditions, (although it will probably start throwing up fascinating "solid" shapes after the first quarter of an hour or so) an "Astro" Lamp should take about one and a half to two and a half hours (and an "Astro" Mini Lamp about half of this period) to start working continuously, according to such factors as the heat of the room, the presence, according to such factors as the heat of the room, the presence or absence of draughts, local voltage fall-offs, etc. If it takes longer to start in an average room temperature, check that the bulb is correct for your local voltage. A 240 Volt 40 Watt bulb is normally supplied with the lamp, and on no account should a bulb with a different Wattage be used.

If the room temperature is too low (less than about 10 degrees C), the lamp may not start at all. If, on the other hand, the room temperature is too high or if the lamp is run for too long periods (normal running time up to about six hours daily), it will overheat, that is to say it will break up completely into bubbles, in which case it should be switched off immediately.

Repeated overheating may eventually cause clouding, and this will necessitate a refill of Master Fluid (See "After Sales Service" No. 1a): but the best remedy for repeated overheating is to "retard" the action of the lamp to suit its particular environment by means of one of our small capsules of Retarding Fluid, which can easily be applied at home (See "After Sales Service" No. 2).

>Positioning the Lamp.

The lamp should be kept well away from sunlight, as ultra-violet tends to cause colours to fade, and direct sunlight can also cause extreme overheating.

It is important to place the lamp in an effective position. Normally, this should be fairly high up --- at about eye-level, if possible. The right selection of background is also worth experimenting with. The proximity of flowers or plants with matching or complimentary colours will be found most effective.

It is best to place the lamp on a mat so as to avoid any danger of marking --- particularly where a highly polished surface is concerned.

>Periodic Checks.

Any "Solid" which may have remained floating after the lamp has been run should be shaken down gently when the lamp is cold.

It is wise to check from time to time to see that the cap is crewed down firmly --- otherwise some water may evaporate from the Master Fluid. If this happens, the vase can be topped up with distilled water when the lamp is really cold (never cool artificially). but great care must be taken to see that it is not overfilled. To allow sufficient air space for expansion when the lamp heats up, the level of the Master Fluid should also be clearly visible below the cap when the lamp is cold, in normal room temperatures. In a cold room in cold weather, there should be a visible gap of about a quarter of an inch. After refilling it is important to check that the "seal" (the special "Viton" O-Ring in the case of the large vase or the round disc --- foil downwards --- in the case of the Mini and the Nordic vases) is replaced centrally on top of the vase before the cap is replaced and screwed down again firmly.

Finger marks and other blemishes are best removed with a good glass cleaner and soft rag.

Above all, it should be remembered that the lamp should be treated with every possible care and should be handled only when necessary.


Never store the lamp or leave it for long periods if it has been switched on for a few minutes only and he "Solid" has set again unevenly. Run the lamp for at least an hour or two so that, on cooling, the "Solid" assumed a flat surface. Store for long periods in a cool, dark place with an even temperature, and make sure that there is no chance of freezing, as this would crack the glass.

>After Sales Service.

>1. Refillability.

(a) The Master Fluid of the lamp can easily be renewed at your home (when the lamp is cold, i.e., when the base liquid has solidified) should you wish to change the colour of the liquid, or should it have become over-clouded or faded through misuse. (See attached Order Form No. 1a). On no account should the cap be loosened or removed while the lamp is at all warm (and then only when necessary for refilling). Never at any time should any other refill but Master Fluid be used, although distilled water can be used for topping up if evaporation occurs (but see "Periodic Checks" about overfilling).

Master Fluid refills can be supplied in the following Colours: Rose, Primrose, Clear, Yellow-Green or Blue-Green.

(b) The "Solid" also can be renewed (and the colour changed if desired) but since this necessitates a complete refill and special chemical cleaning, it must be done at our factory.

The "Solid" is made in the following colours: Ruby (Red), Amber (Orange), Topaz (Yellow) and Emerald (Green).

>2. Adjustability.

(a) Retarding Action (See Attached Order Form No. 2)

If you wish your lamp to run in gotten than normal conditions (or for longer than normal periods) you may find it necessary to slow down the action slightly. For this we can supply you with a small capsule of "Retarding Fluid".

(b) Accelerating Action (See Attached Order Form No. 3)

If, on the other hand, you wish to accelerate the action of your lamp because its operation has become: "sluggish" (usually because the temperature is lower than normal), then we can supply you with a capsule of "Accelerating Fluid" (but first check to see that a 40 watt bulb of the right voltage is being used --- see middle paragraph of left inside page).

::: Click to hear an interview regarding Edward Craven Walker :::

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