A lecture on the progress of physical science since the opening of the London Institution / by W.R. Grove.

  • Grove, W. R. (William Robert), 1811-1896.
Date:
1842
Catalogue details

Licence: Public Domain Mark

Credit: A lecture on the progress of physical science since the opening of the London Institution / by W.R. Grove. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the construction of float-boards, and the proper curve to be given to them: by great perseverance lie has succeeded in introducing his improvements generally throughout France, where, from the absence of coal-fuel, water-power is of far more value than with us. Undershot and breast-wheels of his construction yield, when compared with those of the old form, one-third more power with the same expense of water. The experiments of Morin, a pupil of Poncelet, made at the cost of the French Government, have given to our know- ledge of the effects of friction a high degree of precision and certainty. In this country Professor Willis has contributed to advaiicc Mechanics by a systematic classification, and has established the mathematical relation of the velocities of the different moving parts of machines. Professor Moseley has recently published a paper, in which he lays down rules for the deter- mination of what he calls “ the Modulus” of a machine. This term I will endeavor to explain to you. In every ma- chine there are four mechanical elements :—first, the work done by tbe motive power upon the driving points: secondly, that expended upon the working points, that is those parts of the machine where the original motive power is utilised: thirdly, the work w'asted or expended upon the prejudicial resistences, such as friction, aerial-opposition, etc.: and fourthly, that accumulated in the moving elements; as for instance in a fly-wheel, where the power impressed by the machine when in its most advantageous mechanical situation is accumulated, and again evolved when the initial power decreases. Between these four elements there exists a rela- tion, which is always the sfime for the same machine, and different for different machines ; this relation is what Mr. Moseley calls “ the Modulus”, and this relation he determines for simple and compound machiues. I may not, on the present occasion, experimentally eluci- date to you the various practical improvements which lUia- chines have undergone during the period we arc considering, but we need little experiment when a daily survey of the now-familiar ai’ts must force on the mind a conviction of