OCTOBEH 11, 1895.] 



SCIENCE. 



467 



have materially strengthened the view that 

 alloys are closely analogous to saline solu- 

 tions. Professor Eoberts-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 conse- 

 quently possible to fortell, in a great meas- 

 ure, the effect of anj' given combination. 



Metallurgical science has brought alumin- 

 ium into use bj^ cheapening the process of its 

 extraction ; and if by nisans 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 

 utiUze the metal or its alloys in increasing 

 the spans of our bridges, and in affording 

 strength and lightness in the construction 

 of our ships, bat 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 navi- 

 gate the air. 



As early as 1820 the steam engine had 

 been applied by Gurnej^, Hancock and oth- 

 ers to road traction. The absurd impedi- 

 ments placed in their way by road trustees, 

 which, indeed, are still enforced, checked 

 any progress. But the question of mechan- 

 ical traction on ordinary roads was practi- 

 cally shelved in 18.30, at the time of the for- 

 mation of the British Association, when the 

 locomotive engine was combined with a 

 tubular boiler and an iron road on the Liv- 

 erpool and Manchester Railway. Great, 

 however, as was the advance made by the 

 locomotive engine of Eobert Stephenson, 

 these earlier engines were only toys com- 

 pared with the compound engines of to-day 

 which are used for railways, for ships, or 

 for the manufacture of electricity. Indeed, 

 it may be said that the study of the laws of 

 heat, which have led to the introduction of 

 various forms of motive power, are gradu- 

 ally revolutionizing all our habits of life. 



The improvements in the production of 



iron, combined with the developed steam 

 engine, have completely altered the condi- 

 tions of our commercial intercourse on land; 

 whilst the changes caused by the effects of 

 these improvements in shipbuilding and on 

 the ocean carrj'ing trade have been, if any- 

 thing, still more marked. At the founda- 

 tion of the Association all ocean ships were 

 built by hand of wood, propelled by sails, 

 and manoeuvred by manual labor; the ma- 

 terial limited their length, which did not 

 often exceed 100 ft., and the number of 

 English ships of over 500 tons burden was 

 comparatively small. In the modern ships 

 steam power takes the place of manual la- 

 bor. It rolls the plates of which the ship 

 is constructed, bends them to the required 

 shapes, cuts, drills, and rivets them in their 

 place. It weighs the anchor; it propels the 

 ship in spite of winds or currents ; it steers, 

 ventilates and lights the ship when on the 

 ocean. It takes the cargo on board and 

 discharges it on arrival. 



The use of iron favors the construction of 

 ships of a large size, of forms which afford 

 small resistance to the water, and with 

 compartments which make the ships prac- 

 tically unsinkable in heavy seas or by col- 

 lision. Their size, the economy with which 

 they are propelled, and the certainty of 

 their arrival, cheapen the cost of transport. 

 The steam engine, by compressing air, gives 

 lis control over the temperature of cool 

 chambers. In these not only ft-esh meat, 

 but the delicate produce of the Antipodes, is 

 brought across the ocean to our doors with- 

 out deterioration. Whilst railways have 

 done much to alter the social conditions of 

 each individual nation, the application of 

 iron and steam to our ships is revolutioniz- 

 ing the international commercial conditions 

 of the world ; and it is gradually changing 

 the course of our agriculture as well as of 

 our domestic life. 



But, great as have been the developments 

 of science in promoting the commerce of the 



