materials and equipment
Station, Ventilation of internal bath- rooms and WC's in dwellings'.
When the bathroom light is switch- ed on, air extraction commences. After the light has been switched off, the fan continues to operate until 750 cu.ft. of air has been extracted. If the
SURVEYING INSTRUMENT
Three-dimensional viewing of stereoscopic aerial photographs up to 9in. square is provided by a compact viewer made by Fairey Surveys Ltd., Reform Road, Maidenhead, Berks., UK.
The instrument comprises an eye- piece, consisting of a lens and silvered prism for each eye that receives re- flected images from two front-silvered glass mirrors embodied in wing pieces. The wings which are attached to the eye-piece, effectively enlarge the dis- tance between the viewer's eyes to
Fairey Stereoviewer
approximately 1ft., so that the whole stereoscopic overlap may be viewed at one setting.
The eyepiece and wings are mount- ed above a 2ft. x 1ft. baseboard. Any adjustment required is made to the position of the photographs rather than to the instrument.
CALCULATOR
The HP 9100B is described by its makers as the first fully-expandable desktop computing-calculator system. No special computer training is needed to operate it.
The calculator is supplied with a library of more than 100 programmes, compiled to meet a wide variety of needs. Ancillary equipment offered includes a plotting table, on which graphs can be recorded either as a series of points or as a continuous curve, a calculator printer which can reproduce written characters at speeds up to 150 lines per minute with up to
15 characters per line, and an optical card-reader which enables the calcula- tor to read instructions on cards marked with a soft-lead pencil.
HP 9100B calculator
All these accessories simply plug into the calculator, and several addi- tional accessories are currently under development. Technical features of the HP 1900B include a two-page mem- ory, allowing up to 392 programme steps or 32 data registers; a subroutine capability permitting instant access to subroutines and return from any point in the register; a key-operated facility for recalling data to the “X” register; and a dual display of programme steps designed to simplify programme edit- ing.
Logarithmic, trigonometrical and mathematical functions are each per- formed by a single key stroke, and the range of numbers that the machine can handle at one time are from I x 10-98 to 9.999,999,999 x 1099.
The makers are Hewlett-Packard Ltd., 224 Bath Road, Slough, UK. Agents include: Schmidt & Co. (HK) Ltd.; Mecomb Malaysia Ltd.; Mechani- cal and Combustion Engineering Co. Ltd., Singapore; and Hwa Sheng Elec- tronic Co. Ltd., Taiwan.
VENTILATION UNIT
Airflow Developments Ltd., High Wycombe, UK, have produced a new toilet/bathroom ventilation unit which they call the Airflow Loovent.
It is a compact unit with clean lines, measuring 8 in. x 8 in. and pro- jecting 41⁄2 in. from the wall. The volume of air extracted and the time delay mechanism control conform to Digest 78 of the Building Research
Airflow Loovent
light is switched on again during the period when the fan is still operating, the cycle is automatically re-started.
Hong Kong agents are Harvey Main Co. Ltd.
DOOR FURNITURE
Latest Allgood Modric knobset, model A9600, makes use of an attrac- tively designed knob which takes the form of a short cylinder, flared slightly at its front face and flanged on its inside edge. It has an overall diameter of 2 5/8in. and is made of silver-ano- dised aluminium.
Knobsets in the A9600 range suit door thicknesses from 1 3/8in. to 1 7/8 in. and can be supplied in versions for either a 3 3/4in. or 5in. backset. The distance across a pair of knobs,
Allgood Modric knobset
from one front face to the other, re- mains constant at 6 3/8in., regardless of the door thickness.
Versions of the basic design include normal and non-turning plain knobs, emergency release knobs, turning and non-turning cylinder knobs with an oc- cupancy indicator, push-button knobs, turn-button knobs and universal knobs.
The makers are C. & S. Allgood Ltd., 297 Euston Road, London, N.W. 1.
LIGHTING FITTINGS
A selection of cylindrical glass light fittings has been added to the decora- tive incandescent range available from
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