Page:Popular Science Monthly Volume 60.djvu/151

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THE NATIONAL PHYSICAL LABORATORY.

is too little, but it is all we can do with our present building. The necessary pumps are being fitted to give the pressure and we shall have a lift set up along the column so that the observer can easily read the height of the mercury.

This column will serve to graduate our standard gauges up to 20 atmospheres, above that we may for the present have recourse to some multiplying device; a very beautiful one is used at the Reichsanstalt and by Messrs. Schaffer and Budenberg, but we are told we must improve on this.

Again, there are the ordinary gauges in use in nearly every engineering shop. These in the first instance have probably come from Whitworth's or nowadays, I fear, from Messrs. Pratt & Whitney or Brown & Sharp, of America; they were probably very accurate when new but they wear, and it is only in comparatively few large shops that means exist for measuring the error and for determining whether the gauge ought to be rejected or not.

Hence arise difficulties of all kinds. Standardization of work is impossible. The new screw sent out to South Africa to replace one damaged in the war will not fit, and the gun is useless. A long range of steam piping is wanted; the best angle pieces and unions are made by a firm whose screwing tackle differs slightly from that of the factory where the pipes were ordered. Delays and difficulties of all kinds occur which ready means for standardization would have avoided. Here is scope for work if only manufacturers will utilize the opportunities we hope to give them.

In another direction a wide field is offered in the calibration and standardization of glass measuring vessels of all kinds—flasks, burettes, pipettes, etc.—used by chemists and others. At the request of the Board of Agriculture we have already arranged for the standardization of the glass vessels used in the Babcock method of measuring the butter fat in milk and in a few months many of these have passed through our hands. We are now being asked to arrange for testing the apparatus for the Gerber & Leffman-Beam methods, and this we have promised to do when we are settled at Bushy. Telescopes, opera glasses, sextants and other optical appliances are already tested at Kew, but this work can and will be extended. Photographic lenses are now examined by eye; a photographic test will be added. And I trust the whole may be made more useful to photographers.

I look to the cooperation of the Optical Society to advise how we may be of service to them in testing spectacles, microscope lenses and the like.

The magnetic testing of specimens of iron and steel again offers a fertile field for enquiry.

If more subjects are needed it is sufficient to turn over the pages