The Whitworth Measuring Machine; Including Descriptions of the Surface Plates, Gauges, and Other Measuring Instruments, Made by Sir Joseph Whitworth, Bart., C.E. F.R.S. D.C.L. LL.D. &C (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1877 Excerpt: ...and the sense of touch--the delicacy of the nerves of feeling being, in fact, a thing quite disregarded and neglected by all others who had applied themselves to improving mechanical measurement; and it has been in developing to the fullest extent the results obtained by the contact of surfaces which were almost ideal in their excellence that a system has grown up which stands quite alone and removed from all thoughts of rivalry or competition. Now that the result has been made known, and we are able to assign the value of minute differences in size which were previously only guessed at, as something hopelessly beyond the reach of exact observation, it is perhaps difficult to realise the view which the subject presented in the first instance, and before the problem had been solved. But, nevertheless, the true way of learning a new thing is to attempt this realisation, and the enquirer may with advantage put himself in the position of one beginning from the standing-point of what was known before the improvement was originated, and then working step by step to its final accomplishment. And, indeed, those who thus approach the subject for the first time can scarcely fail to be interested in a notice of experiments which demonstrate the possibility of making certain minute differences of size which are simply felt, and are not seen, a measurable quantity. We are so much in the habit of defining all minute linear intervals by the aid of some form of microscope that it is a new thing to seek for the power of measurement anywhere but in optical contrivances. It is the originality of the conception that we can measure without distinctly bringing into the field of vision the thing measured which gives the system now under discussion an interest that it would not ot...