SIR ROBERT HADFIELD, BART. 23 



exerted on its constitution by the various treatments, thermal and 

 mechanical, to which the metal is lawfully subjected ; and its patho- 

 logy, that is, the action of impurities and defective treatments upon 

 its normal constitution. 



Fortunately Metallography does more than reveal the proximate 

 composition of metals. It is a true dissecting method which lays 

 bare their anatomy — that is, the physical grouping of the proximate 

 constituents, iheir distribution, relative dimensions, etc., all of which 

 necessarily affect the properties. For two pieces of steel, for instance,' 

 might have exactly the same proximate composition — that is, might 

 contain, let us say, the same proportion of pearlite and ferrite, and still 

 differ quite a little as to strength, ductility, etc., and that because of a 

 different structural arrangement of the two proximate constituents ; 

 in other words, because of unlike anatomy. 



It is not to be supposed that the path trodden during the last score of 

 years was at all times smooth and free from obstacles. Indeed, the 

 truth of the proverb that there is no royal road to knowledge was 

 constantly and forcibly impressed on the minds of those engaged in 

 the arduous task of lifting metallography to a higher level. 



Its short history resembles the history of the development of all 

 sciences. At the outset a mist so thickly surrounds the goal that 

 only the most courageous and better equipped attempt to pierce it 

 and perchance they may be rewarded by a gleam of light. This gives 

 courage to others, and the new recruits add strength to the besieging 

 party. Then follow the well-known attacking methods of scientific 

 tactics and strategy, and after many defeats, and now and then a 

 victorious battle, the goal is in sight, but only in sight and never to 

 be actually reached, for in our way stands the great universal mystery 

 of nature : what is matter ? what is life ? 



Nevertheless there is reward enough for the scientist in the feeling 

 that he has approached the goal, that he has secured a better point of 

 vantage from which to contemplate it. The game was worth the 

 candle, and if scientific workers must necessarily fail in their efforts 

 to arrive at the true definition of matter, whatever be the field of their 

 labour, they at least learn a great deal concerning the ways of matter, 

 and it is with the ways of matter that the material world is chiefly 

 concerned. Hence the usefulness of scientific investigation, hence 

 the usefulness of metallography." 



Among the many workers who have contributed to the progress of 

 Metallography may be mentioned : — Arnold, Benedicks, Belaiew, 

 Brearley, Carp3nter, H. LeChatelier, Campbell, Desch, Edwards, Elliot, 

 Guillet, Gulliver, Giolitti, Hatfield, Honda, Howe, Humfrey, Hudson, 

 Zay Jeffries, Law, Martens, McCance, Osmond, Portevin, Roberts- 

 Austen, Rosenhain, Robin, Sorby, Sauveur, Stead, Thompson, Werth. 



In the valuable Pocket Encyclopaedia on " Iron and Steel " by 

 Mr. Hugh P. Tiemann, B.S., A.M., with an introduction by Professor 

 H. M. Howe, some thirty pages are devoted to Metallography. The 

 book contains a most excellent summary of the terms used in this 

 Branch of the Science of Metallurgy, treating of the constitution and 

 structure of Metals and Alloys, also their relation to physical 

 properties. 



