Machinery at the Exhibition. 427 



There are many points in which, the present Exhibition re- 

 minds ns of the progress which has been made. Castings are 

 now produced with ease that but a short time since would not 

 have been even attempted; cylinders are now bored and 

 finished which a few years ago would have been considered of 

 unmanageable size; forgings are executed which not long ago 

 would have been out of the question. To prove the accuracy 

 of these assertions, we have only to direct the attention of our 

 readers to the connecting-rod and crosshead exhibited by 

 Maudslay and Field, and to the cylinder and crank-axle exhi- 

 bited by Penn and Sons. 



Another improvement which has been introduced, is the use 

 of steel more generally, and in very much larger quantities. 

 Its advantages have always been admitted ; it is far more to be 

 depended on than iron, and, with the same strength, may be 

 much lighter and less bulky ; but, until recently, its cost and 

 the difficulty of obtaining it in large masses prohibited its more 

 general application. These obstacles have, however, been re- 

 moved. The production of steel from pig-iron was proposed 

 by Bessemer in 1856 ; but the process he used was for some 

 time not very successful, an impure steel being the result. It 

 was, however, subsequently ascertained that, when pure ores, 

 which are very abundant, are employed, the quality of the pro- 

 duct is everything that can be desired. The vast quantity 

 manufactured by Bessemer' s method in this and other countries 

 is a proof of its excellence. Everything is at present made of 

 steel; tires, rails, axles, bells, cannon, steam boilers, etc.; and 

 it is now produced in enormous masses : — one block of steel in 

 the western annex weighs twenty tons, and there are seve- 

 ral others of very great size. Bessemer' s process is founded 

 on common sense ; he takes just as much carbon from the pig- 

 iron, as will leave any required quality of steel or malleable iron. 

 In the roundabout way that was previously used, all the carbon 

 was removed to form malleable iron, and then some was 

 restored to change the malleable iron into steel. The rational 

 method is now used everywhere, and the quantity of steel ex- 

 hibited by the various countries is very great. 



This is not the only illustration which the present Exhibi- 

 tion affords, of the application of scientific principles to practical 

 purposes. Philosophy had taught us long ago that evaporation 

 causes cold, and established the truth of this by some experi- 

 ments on a small scale. But our knowledge on this point is 

 now practically applied : and ice is made abundantly at the 

 Exhibition by steam, the required cold being produced by suc- 

 cessive evaporations of ether. 



But to whatever side we turn, while we survey the wonders 

 which are amassed in this great storehouse of the productions 



