140 



NATURE 



\yune 8, 1876 



LOAN COLLECTION OF SCIENTIFIC 



APPARA TUS 



SECTION— MECHANICS 



PRIME MOVERS^ 



HTHE subject on which I have now the honour to address you, 



■*- the subject which is to occupy our attention to-day, is that 



of prime mover?, that is to say, we are about to consider that 



class of machines which, to use the words of Tredgold, "enable 



the engineer to direct the great sources of power in nature for 



the use and convenience of man." 



Although machines of this kind are, in truth, mere converters 

 or adapters of extraneous forces into useful and manageable 

 forms, and have not any source of life, power, or motion, in 

 themselves, nevertheless they impress us with the notion of 

 vitality ; and it is difficult to regard the revolving shaft of a 

 water-wheel or turbine, set in motion by some hidden stream, or 

 to {;aze upon the steam-engine actuated by an unseen vapour, 

 without, as I have said, the idea being raised in our minds that 

 the machines on which we are looking arc really endowed with 

 some kind of life. 



The invention of such machines marks a very great step in 

 the progress of mechanical science in the world, as it com- 

 mences an era distinct from that in which mere machines to be 

 acted on by human or animal muscular force were alone in 

 existence. Machines such as these, hi^jhly useful as they may 

 be, are, after all, only tools or implements more or less ingenious 

 and more or ks3 complex. 



Mankind could not have been very long upon the earth before they 

 must have found the reed and must have discovered the utility 

 of some kind of tool or implement ; they must soon have found 

 that the direct action of the power of the arm, which was not 

 enough by itself to break up some obstacle, became sufficient if 

 that aclion wtre applied by the wielding of a heavy club, or 

 through ihe putting into motion of a large stone, and thus the 

 hammer or its equivalent must have been among the earliest of 

 inventions. Sucti an implement must soon have taught its users 

 that muscular force could be exercised through a considerable 

 space, could be stored up, and could be delivered in a concen- 

 trated form by a bl jw. 



Simiiarly it could not have been long before it must have been 

 found that to rai^e water in the hollow of the hand by repeated 

 efforts was not so convenient a mode as to raise it in a bent leaf 

 or in a shell, and in this way another implement would speedily 

 be invented. We might pursue this line of speculation, and 

 doing so we should readily arrive at the conclusion that (without 

 attributing to the early inhabitants of the earth any profound 

 acquaintance with mechanics) the hammer, the lever, the wedge, 

 and other simple tools and utensils, must soon have come into 

 existence ; and we should also be led to believe that when, even 

 with the aid of tools such as these, a man singly could not ac- 

 complish any desired object, the expedient of combining the 

 power of more than one man to attain an end would soon be 

 thought of, and that the requisite appUances, such as large 

 beams uted as levers, numerous ropes (which must very early m 

 the history of the world have been iwisied from filaments) and 

 matters of that kind, would come into use. For a corroboration 

 of this view, ii one wtre wanted, the Jatt may be cited that on 

 the discovery of any isolated savage community it always is 

 found to have advanced thus far in mechanical art. 



But passing from such machines as these, which are rather 

 of the character of tools and implements, than machines, as we 

 now popularly use the word, one knows that even complicated 

 mechanism for the purpose of enabling muscular force to be more 

 readily applied, is of very ancient date. On this point I will 

 quote from only one book, that is the Bible, where, at the loth 

 and nth verses of the nth chapter of Deuteronomy, a state- 

 ment is made clearly indicating that in Egypt irrigation was 

 carried on by some kind of machine v. orked by the foot; whether 

 the tread wheel with water-buckets round about it mentioned by 

 Vitruvius, cr whether the plank-lever with a bucket suspended 

 at one end and worked by the labourer running along the top of 

 the lever to the other end (an apparatus even now used in Inaia), 

 we do not know ; but that it was some machine worked by the 

 foot is clear, the statement being that when the Israelites had 

 reached the I'romised Land they would find it was one abound- 

 ing in streams, so as to be naturally watered, and that it would 

 not require to be watered by the foot as in Egypt. Again, in 



I Address delivered by F. T. Bramwell, C.E., F.R.S., one of the vice- 

 presidents of the Section, May 25. 



Chronicles it is related that King Uzziah loved husbandry, and 

 that he made many engines, unhappily not in connection with 

 agriculture, but for warlike purposes, "to shoot arrows and 

 great stones withal." Fuither, in the yth chapter of the Book 

 of Job, we have the comparison of the life of man passing away 

 swifter than a weaver's shuttle ; this points unmistakeably to 

 the fact that there must in those days have been in existence a 

 loom capable of weaving fabrics of such widths that the shuttle 

 required to be impelled with a speed equal to a flight from one 

 side of the fabric to the other, and no doubt such a fabric must 

 have been made in a machine competent at last to raise and 

 depress alternately the halves of the warp threads. The potter's 

 wheel also is frequently mentioned in the Bible. 



Such instances as these arc sufficient to show that considerable 

 progress must have been made in the very earliest days of his- 

 tory in the construction of machines whereby muscular force 

 was conveniently applied to an end ; but if we leave out of 

 account, as we fairly may, the action of the wind in propelling 

 a boat by sails, and the action of the wind in winnowing grjiin, 

 I think we shall be right in considering that in the times of which 

 I have been speaking there did not exist any machine in the 

 nature of a power-giver or prime mover. 



Doubtless the want of a greater force than could be obtained 

 from the muscles of one human being must have soon made itself 

 felt ; and intelligent men, conscious of their own ability and of 

 their mental power of directing a large amount of work, must 

 have been grieved at finding the use of that power circumscribed 

 by the limited force of their own bodies, and therefore early in 

 the world's history there must have been the attempt, by the 

 offer of some consideration or reward, to induce other men (men 

 gifted with equal or stronger muscles, but probably not with 

 equal minds) to work under the directions of these men of supe- 

 rior intelligence. But when such aid as this became insufficient, 

 the way in which, in all probability, the people of those days 

 endeavoured to satisfy the further demand would be to make 

 captives of their enemies and to reduce them into a state of 

 bondage, to grind at the mill, to raise water, or, yoked by in- 

 numerable cords and beams to some heavy chariot or sledge, to 

 draw along the huge blocks required in the foundations of a 

 temple, or for the building of a pyramid, or to act in concert 

 on the many oars of a galley, although by what means this last- 

 named operatiun was performed is not very clear. Doubtless 

 under this condition of thin-s there must have been an amount of 

 human suffering which is too Irightful to be contemplated. 



Such machines as those to which I have called attention could 

 not have been invented and brought into use without the exer- 

 cise of much mechanical skill ; but considerable as this skill must 

 have been it had never originated a prime mover ; it had given 

 no source of power to the world, but had left it dependent on 

 the muscular exertions of human beings and of animals. 



Great, then, was the step, and a most distinct era was it in 

 mechanical science, when for the first time a prime mover 

 was invented and a machine was brought into existence which, 

 utilising some hitherto disregarded natural force, converted it 

 into a convenient form of power, by which as great results could 

 be obtained as were obtainable by the aggregation of a large 

 number of human beings, and could be obtained without bondage 

 and without affliction. 



There are probably few sights more pleasing to one who has 

 been brought up in lactones than to watch a skiltul workman 

 engaged in executing a piece of work which requires absolute 

 mastery over the tools that he uses, and demands that they 

 should have the constant guiding of his intelligent mind. Handi- 

 craft work of such a kind borders upon the occupation of the 

 artist, and to see such work in the course of execution is, as I 

 have said, a source of pleasure. But when descending from this 

 the work becomes more and more of the character of mere repe- 

 tition, and when it is accomplished by the aid of implements 

 which, from their very perfection require but little mind to direct 

 them, and demand only the use of muscle, then, although the 

 labour, when honestly pursued, is still honourable, and therefore 

 to be admired, there comes over one a feeling of fear and of 

 regret that the man is verging towards a mere implement. But 

 when one sees, as I have seen in my time, in England, and as 

 I have seen very recently on the Continent, men earning their 

 living by treading within a cage to cause it to revolve and 

 thereby to raise weights, an occupation demanding no greater 

 exercise of intelligence than that which is sufficient to start, to 

 stop, and to reverse the wheel at the word of command, one 

 does indeed regret to find human beings employed in so low an 



