trim which fits flush to the ceiling. It requires an aperture measuring 6 5/6 in. (160 mm) in diameter, the void depth varying from 4 7/8 to 6 3/4 in. (124 to 171 mm), with either an Atlas VA 100 or VA 150 auxillary reflector. Mazda Kolorlux lamps in 80- and 125-W ratings can also be used depend- ing upon the type of lamp used.
An adjustable lampholder permits the use of a wide range of ES capped lamps: 100- or 150-W, internally silver- ed spot or flood; 150-W PAR 38 spot or flood; and 100- or 150-W GLS lamps fitted in conjunction with ex- ternally mounted control gear.
The makers are Thorn Lighting Ltd., Upper St. Martin's Lane, Lon- don, W.C.2.
SOUND CONDITIONING
Open-plan or landscaped offices can now be 'sound conditioned' by a system developed by Carr & Wilkin- son, 72 Archer Street, Chatswood, NSW 2067, Australia, and marketed by Angus & Coote Acoustics Pty. Ltd., 500 George Street, Sydney.
The system is said to mask conver- sations or unwanted internal or ex- ternal activity noise by introducing specially controlled and contoured sound into the environment. This has the effect of reducing the apparent loudness of adjacent conversation and unwanted noise without interfering with across-the-desk or telephone con- versation. The introduced sound is neutral, unobtrusive and remains in the background sound free from any annoying, distinctive tones.
The source of the introduced sound is a transistorised plastic-encap- suled, controlled spectrum random- sound generator. The sound is ampli- fied and transmitted through a special transducer or loud-speaker arrange- ment. It is possible to produce a wide variety of sound effects, ranging from rolling surf to rustling leaves.
Once installed and tuned, the sys- tem works automatically. Operating times can be determined by an in-built
clock. It can also be set gradually to build up a pre-determined volume so that the ear can become accustomed to the background sound when first switched on.
MOSAICS
Ceramic tiles for internal and ex- ternal use in a wide range of colours, gloss and matt finishes, are guaranteed by their British makers to be fire and craze proof. The mosaics are offered in made-up panels of 30 by 30 cm, sup plied with net backing or paper facing in specific colour schemes.
Individual ceramic pieces are either rectangular 4,8 by 2,3 cm or square 10,8 by 10,8 and 2,3 by 2,3 cm. An
Kervit mosaics
attractive basket weave design is avail- able in 5,39 by 2,698 cm pieces mounted in panels of 26,98 by 26,98 cm. To meet particular wall-finishing requirements, special colours and mosaic patterns can be developed.
The makers are Kervit Ceramics Ltd., Penketh, Warrington, Lancs., UK.
DAMP PROOFING
A pitch polymer damp-proofing course for use between rows of bricks or in concrete or masonry walls has been developed by Marley Tile Co. Ltd., Sevenoaks, Kent, UK.
It is available in two metric thick- nesses, 0.90 mm and 1,25 mm. A special graining gives it good adhesion to mortar, flexibility is retained down to 10 degree C., and it does not be come tacky in temperatures up to 60 degrees C.
The makers claim that the material overcomes the problems of extrusion under load to the point of compressive failure of a wall. Horizontal shear resis- tance is also said to be unlikely before failure of the wall itself.
The pitch resists the transmission of water and is also effective as a water
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