II, — 'THE RISE OF SCIENCE IN INDUSTRY 



completely disentangled from groups of phenomena, that they cannot be 

 defined in words, nor understood if they could be formulated. But after 

 long familiarity^ with the general behavior of materials under stress, a 

 practical expert can, by a process more like instinct than reason, judge 

 how far and in what directions he may safely push his new combina- 

 tions. Thus while the unschooled practician so usually .wastes his en- 

 ergies in unscientific methods and on impossible combinations, but 

 generally carries into successful use his comparatively few well-founded 

 attempts, the student merely of principles and abstract facts so usually 

 originates the ideas upon which progress is founded, and so rarely clothes 

 them with practical bodies. In this chasm between science and art, how 

 much effort and treasure, and even life, are swallowed up year by year. 



These are not theoretical considerations. The blast-furnace, the con- 

 verter, and the open-hearth have already been referred to; let us observe 

 some other illustrations. A bridge-builder will tell us that few structures 

 in his department of engineering fail by reason of mistakes in calculating 

 the strain-sheet, but that the majority of failures arise from vibrations, 

 buckling, rapid wear of important parts, shapes that weaken the material, 

 inequalities in the material, and similar causes which are not stated in 

 books, which assume different aspects under every change of proportions 

 and dimensions, and which can only be inferred by means of a long 

 familiarity with the behavior of similar structures during varying periods 

 of service, and with the processes by which materials and members are 

 fabricated. The builder of a machine like a marine engine, or a loco- 

 motive, or a roll-train, or a steam-hammer, will tell us that, in designing 

 new adaptations, after every stress that can be distinctly analyzed is pro- 

 vided for, mass to resist vibration, changes of shape to insure sound cast- 

 ing, and various modifications which cannot be formulated for the want 

 of even approximately complete knowledge of their conditions, must still 

 be supplied, simply by judgment founded on long observation of phe- 

 nomena under similar conditions. And he will thus explain nine-tenths 

 of the failures. Who can imagine the volume of a book, or of an author, 

 which should adequately teach the principles of construction as affected 

 by the chiefest of all practical considerations — the economics of the 

 foundry, the forge, and the machine-shop? With the tools and facilities 

 at hand, what divisions of a particular structure, what shapes and sizes 

 and methods of joining can be made cheaply as well as strong and effi- 

 cient, in all the infinite forms of mechanism? Obtaining such facts from 

 any other source than personal practice, would be like an oarsman study- 

 ing a book to know when and how in the race he must husband his 

 power, or like a wrestler looking out in a cyclopedia the probable feints 

 of his antagonist. The successful constructor will assure us that no pos- 

 sible training in the school, nor any genius in invention can build eco- 

 nomically without such a knowledge of the shop as the athlete has of 

 the possibilities of muscular strength and agility. 



These arts have been selected as examples, not because they chiefly 

 depend on skill, but because they so largely involve the highest formu- 

 lated mathematical knowledge. How much more important, then, is 

 practical training in those departments where physical laws are very in- 

 completely understood and formulated. How far short of practical sue- 



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