AT this Exhibition, which will remain open until October 2, there is so much of scientific interest that it is possible only to select a few representative items as indicative of the extent to which the results of research are being utilized with the aid of mechanical ingenuity. One gets, for example, a definite impression of a universal effort being made to deal with the problem of noise both by improvements in design and workmanship and by the adoption of new types. At one stand a noiseless sliding door is exhibited, and of silently operating machinery a notable example is the Mirrlees-Imo pump for oils and other liquids. This has only three moving parts—a central screw which is the actual pumping unit, and two side screws which act as seals and are rotated merely by their engagement with the central screw. In high-speed Diesel engines vibration is destructive of the exhaust pyrometers which, by the close relationship between exhaust temperature and horse power, are necessary to ensure that an even and efficient balance is maintained between the several cylinders. Messrs. Negretti and Zambra are exhibiting pyrometers in which a few inches of the tube immediately below the instrument have been replaced by a helical spring, and instruments so constructed are to be seen mounted on a vibrating table yet relatively unaffected.