CHAP. IV., 4.] 



MECHANICS. BRUNEL MR BABBAGE. 



81 



(370.) 

 'he block- 



lachinery 



! results. 



(371.) 

 ive an 



ipulse to 

 ichanics. 



(372.) 

 troduc- 

 >n of me- 

 inism 

 ;o work- 

 jps. 



use, but the invention of Brunei was not less im- 

 portant as creating an epoch in art. Not only is 

 it possible to execute in a comparatively short 

 time, and with a prodigious economy, objects such as 

 blocks and pulleys, which are required in vast num- 

 bers and precisely alike, but the nicety and accuracy 

 of the manufacture is thereby increased, and owing 

 to the facility with which inanimate force may be 

 concentrated on machinery, works which transcend 

 the power of unaided muscular labour are as surely 

 and exactly executed as those of smaller dimensions. 

 For example, by no enlargement of the common 

 turning-lathe would it be possible to construct an 

 accurately turned iron steam-cylinder 8 feet or more 

 in diameter, which is yet readily executed under the 

 direction of a very ordinary workman by means of 

 steam power and self-acting machinery. 



The block-machinery at Portsmouth consists of a 

 series of engines impelled by steam, and by means of 

 > which the materials of wood and metal employed in the 

 construction of ships' blocks are reduced to exact forms 

 in graduated sizes, and are finally put together with 

 very little manual labour. These machines, with the 

 exception of the turning-lathe and circular saw, were 

 wholly new, and, it is stated, were devised in part by 

 General Bentham, who gave to Brunei at least the 

 benefit of his advice and previous experiments. In 

 some of them we have the first germ of implements 

 now used by every machine-maker in the kingdom ; 

 and the ingenuity of the movements, and the variety 

 of effects produced, earned for this great invention a 

 just celebrity. Such a beginning could not have 

 been made without the aid of government. To con- 

 struct the tools was an expensive and troublesome 

 business, and to start the manufactory cost L. 53,000, 

 which was speedily saved by the economy of the pro- 

 cess. In the course of a year 140,000 blocks of no 

 less than 200 different patterns were produced, and 

 the number of workmen was diminished in the pro- 

 portion of about 11 to 1. As a reward, Mr Brunei 

 received L.16,000, being two-thirds of the first year's 

 saving, itself a sufficient proof that he was the bona 

 fide inventor of this admirable apparatus, whatever 

 hints he may have received from his immediate su- 

 perior. 



So successful an experiment produced ultimately, 

 though with characteristic slowness, its effect on the 

 mercantile world ; nearly twenty years elapsed before 

 such a splendid example of ingenious economy and 

 artistic precision was at all generally imitated. Yet 

 before his death, Sir Marc Brunei saw the fruit of his 

 ingenuity almost indefinitely multiplied in the work- 

 shops of London, Manchester, Glasgow, Newcastle, 

 and Birmingham, and highly appreciated if less ex- 

 tensively imitated abroad. 



The more we reflect on the comparative state of the 

 arts now and a century ago, the more we shall find 

 reason to estimate highly the introduction of correct 

 and scientific ideas of machinery and of tools for con- 



structing other machines and structures. It was, in 

 fact, the necessary complement of the invention of 

 the steam-engine. Watt contrived the mighty Heart 

 which was to give a new impulse to social life, Bru- 

 nei and others of the same stamp added limbs and 

 muscles, whereby its energies were rendered tho- 

 roughly practical. The sixteenth, seventeenth, and 

 part of the eighteenth centuries, had given to the 

 world designs for countless mechanical contrivances, 

 often highly original and ingenious. But many 

 were grounded on fallacies, and others belong to 

 the class of elaborate trifles. At that period the 

 slide-rest of the turning-lathe, the planing machine, 

 and the circular saw, were practically unknown ; at 

 least the two former, which are incomparably the 

 most important inventions of their class, and which 

 belong to no certain author, having almost imper- 

 ceptibly come into use the slide-rest about the Slide-rest 

 end of the last century, the planing machine as ? nd P lan " 

 lately as about 1820. The former of these readily |jf n a ~ 

 forms surfaces of revolution with geometrical accu- 

 racy, the latter plane surfaces, and in either case 

 the application to metals is most important. The 

 circular saw and slide- rest form part of Brunei's 

 series of machines, and he afterwards constructed the 

 former on a very great scale for the manufacture of 

 wooden veneers. To them he added the mortising 

 machine, and these, it will be seen (together with the 

 planing engine), form the staple of the magnificent 

 and varied apparatus with which, driven by the gi- 

 gantic power of steam, our mechanical factories are 

 now so generally provided. We again repeat that 

 the triumphs of art in which our generation glories, 

 our railroads, our locomotives, our crystal palaces, 

 and our steam navies, would have been impossible 

 feats but for the improvement of tools and the substi- 

 tution of steam for muscular power. 



Every one is, however, aware that Brunei owed his (373.) 

 reputation to other achievements as well as his im- TheThames 

 provements of mechanical tools. The Thames Tun- Tunnel - 

 nel will ever be considered as his most arduous tri- 

 umph. It is a structure of exquisite firmness laid 

 in a quicksand. It will endure like the cloaca of 

 regal Rome, when the palace and the cathedral have 

 crumbled to dust. Yet here also we perceive that 

 it was Brunei's exquisite mechanical tact and inge- 

 nuity which enabled him to succeed. The problem 

 of the tunnel is not one of balancing vaults ; the sta- 

 tical conditions of stability are simple enough, and 

 it was not in the solution of such that Brunei pecu- 

 liarly excelled. The practical problem was to intro- 

 duce a rigid tube of brick horizontally into the 

 middle of a quaking mass of mud ; and the solution 

 was the invention of a tool which should enable men 

 to make the excavation and to proceed with the 

 building in safety. It was the shield which carried The shield. 

 the tunnel under the Thames, a moveable vertical 

 frame of cast iron, provided with thirty-six cells, in 

 each of which a man was placed with a pick to ex- 



