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Subsidiary Meteorological Radar. —An experimental equipment was constructed, using a surplus airborne 3 cm. wave radar type ASD and a 4 ft. paraboloid mounted on a gun turret. Performance was satisfactory in following a standard 17 in. target to 30,000 yards with adequate accuracy. It was decided, however, that the surplus radar parts were too unreliable and the cost of modern commercial replacements was too high, and since the operational requirement became less important the project has now lapsed. Vehicle-speed Indicator.—Some modifications resulting in higher accuracy and greater operational ranges have been made to the equipment during the year. The speed of trucks and buses may now be determined at ranges of some hundreds of yards with an accuracy of the order of two miles per hour. The equipment has been used continuously by the Transport Department with considerable success, and tenders have been called for construction of one or more additional sets. STANDARDS Instrument Calibrations— Instrument and other calibrations performed during the year number approximately 230, certificates having been issued for a large number of these. Many of the instruments which have been inspected are of " working " quality, and the number of high-grade substandards submitted is still small. Of the number above, some 95 were electrical calibrations, 31 were connected with linear standardization, 11 with temperature standardization, 10 with mass, and 17 with various other standard measurements. A total of 83 limit gauges for engineering production have been inspected. Calibrations and other " pure " measurements continue to occupy most of the time of this laboratory. Temperature Standards. —Main items of equipment are still awaited from overseas, and activities are confined to the preparation of the various " fixed points " that define the temperature scale. A furnace for realizing the gold point (.1063°c.) was built during the year, and has been used for standard thermocouple calibrations at this temperature and for investigating thermocouple contamination. A number of standard thermometers is still to be returned from Australia, where they are being re-calibrated. Standard Cells.—ln conjunction with routine calibrations of standard cells, which are basic to electrical measurements, a study was made of the thermal sensitivities of cells of various types, and this has resulted in better techniques of calibration at the laboratory. In this work, cells were kept at various temperatures and accurate comparisons made more or less continuously for a week with the laboratory standards. The electromotive forces of both saturated and unsaturated cells were measured, and the various " hysteresis " effects peculiar to the cells were demonstrated. General Metrology, &c.—ln addition to the routine servicing work summarized above, work has been done on the stability of various drawing materials used for making profile layouts; on the surface finish of ground and lapped quartz crystals; on various hydraulic systems of force measurement; on the refractive index of butterfat; and on the use of electrical anemometers in relation to the flow of air in pneumatic amplifying systems. An interferometer for studying the thermal properties of refractory materials is being prepared for the Pottery and Ceramic Research Association.

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