26 REPORT— 1895. 



In 1856 Bessemer brought before the British Association at Cheltenham 

 his brilliant discovery for making steel direct from the blast furnace, 

 by which he dispensed with the laborious process of first removing the 

 carbon from pig-iron by puddling, and then adding by cementation the 

 required proportion of carbon to make steel. This discovery, followed 

 by Siemens's regenerative furnace, by Whitworth's compressed steel, and 

 by the use of alloys and by other improvements too numerous to 

 mention here, have revolutionised the conditions under which metals are 

 applied to engineering purposes. 



Indeed, few questions are of greater interest, or possess more industrial 

 impor'tance, than those connected with metallic alloys. This is especially 

 true of those alloys which contain the rarer metals ; and the extraordinary 

 effects of small quantities of chromium, nickel, tungsten and titanium on 

 certain varieties of steel have exerted profound influence on the manu- 

 facture of projectiles and on the construction of our armoured ships. 



Of lateyears, investigations on the properties and structure uf alloys have 

 been numerous, and among the more noteworthy researches may be men- 

 tioned those of Dewar and Fleming on the distinctive behaviour, as regards 

 the thermo-electric powers and electrical resistance, of metals and alloys at 

 the very low temperatures which may be obtained by the use of liquid air. 



Professor Roberts- Austen, on the other hand, has carefully studied 

 the behaviour of alloys at very high temperatures, and by employing his 

 delicate pyrometer has obtained photographic curves which afford addi- 

 tional evidence as to the existence of allotropic modifications of metals, 

 and which have materially strengthened the view that alloys are closely 

 analogous to saline solutions. In this connection it may be stated that 

 the very accurate work of Heycock and Neville on the lowering of the 

 solidifying points of molten metals, which is caused by the presence of 

 other metals, affords a valuable contribution to our knowledge. 



Professor Boberts-Austen has, moreover, shown that the effect of any 

 one constituent of an alloy upon the properties of the principal metal has 

 a direct relation to the atomic volumes, and that it is consequently possible 

 to foretell, in a great measure, the effect of any given combination. 



A new branch of investigation, which deals with the micro-structure 

 of metals and alloys, is rapidly assuming much importance. It was 

 instituted by Sorby in a communication which he made to the Bi'itisli 

 Association in 1864, and its development is due to many patient workers, 

 among whom M. Osmond occupies a prominent place. 



Metallurgical science has brought aluminium into use by cheapening 

 the process of its extraction ; and if by means of the wasted forces in our 

 rivers, or possibly of the wind, the extraction be still further cheapened 

 by the aid of electricity, we may not only utilise the metal or its alloys in 

 increasing the spans of our bridges, and in affording strength and lightness 

 in the construction of our ships, but we may hope to obtain a material 

 which may render practicable the dreams of Icarus and of Maxim, and for 

 purposes of rapid transit enable us to navigate the air. 



