A MICEOSCOPE for measuring small lengths has recently been put on the market by Messrs. W. Ottway and Co., Ltd., Orion Works, Baling, W.5. The microscope, which gives a magnification of 25, is about 6 ...

WHERE the height of a liquid surface needs to be measured accurately, it is customary to use a needle height-gauge. In a typical gauge a needle point is slowly lowered by a micrometer screw until the ...