H—34

Instrumentation far Research and Survey.—Projects include a photo-electric instrument for observing hairiness in wool and measuring mean length of fibres in wool staples, measurement of moisture content of wool, and repair and overhaul of geophysical instruments, &c. Routine Testing,—Routine tests have been carried out 011 electrical materials and components, including marble and slate, switches, motors, hearing-aid batteries, indicators, microphones, and audiometer apparatus. Radio and Radar Laboratory {a) Radio Research : Frequency Prediction Investigation.—Radio circuit performance compared with long-term ionosphere predictions revealed that correlation was not good. Short-term predictions from overseas compared with sunspot observations made at Carter Observatory were much superior. Further investigations have covered short radio paths, solar noise at radio frequencies, and ionosphere and cosmic-ray research. (b) Radio and Radar Development: Radar in Shipping.—Routine inspection and maintenance of marine radar has been carried out and a simple radar equipment ■operating at 500 mc./s. was installed in m.v. " Ranui." A radar set of special value in navigating close waters has been installed in the " Tamahine." Microwave meteorological radar sets have been completed for Whenuapai and Fiji. The former is giving satisfactory service and the latter is in transit. (c) Canterbury Project. —Field observations on the Canterbury Project ceased about mid-December, 1947. Some ninety observations were made in north-west conditions of varying intensity. It is considered that the data obtained will go far in elucidating the problems involved in the phenomenon of super-refraction, especially on the correlation of abnormal refractive index gradients in the atmosphere with the associated behaviour of U.H.F. radio waves -on wave-lengths from 3 metres to 3 cm. Further, enough data has been obtained to determine an adequate forecasting technique for the intensity of super-refraction under .advection conditions. A full analysis of the results is now proceeding. The whole project has been an excellent demonstration of team-work with New Zealand and United Kingdom scientists -co-operating. Engineering Laboratory Fibration of New Zealand Woods. —A pilot plant is in operation for fibrating New Zealand woods and other materials by the steam explosion process. Southland beech has been the principal timber involved, and pulp produced has been pressed and heated to form wallboard. The results are very encouraging. Hydraulic Model of Maraetai Dam.-r-A model of the spillway and diversion tunnel •of the Maraetai Dam has been designed and is at present under construction. The object of the model is to study the tunnel flows with a view to determining the capacity of the intake, the erosion effects of the issuing jet, and the meeting of various tunnel flows and river flows at the outlet end. Other special equipment produced has been for electro-magnetic separator for ironsands, measurement record of dynamic stresses in bridges under load, and modification of heat treatment of high-speed steels. Routine Testing.—Much routine testing has been carried out. Precision Workshops. —The tool-room has handled during the year 823 requests for the manufacture of machine parts, tools, instruments, and repair of instruments involving nearly 4,000 separate items.

29