CHEMICAL TECHNOLOGY. 



CLASSIFICATION OF THE CHEMICAL ARTS. 



The arts are those processes by which the products of the 

 mineral, vegetable, and animal kingdoms are modified, in a 

 greater or less degree, in order to adapt them to the wants of 

 man. These processes are based on either mechanical or 

 chemical principles ; and while in a large proportion of them 

 mechanics are almost exclusively employed, in an equally large 

 number mechanical operations are merely subservient to chemi- 

 cal action. Hence, a twofold division of the arts is both 

 practicable and convenient. The former is designated as 

 Mechanical Technology, or Practical Mechanics ; the latter, 

 Chemical Technology. 



Among the chemical arts, many are conducted on a large 

 scale, and are properly termed chemical manufactures ; but 

 chemical technology is more comprehensive, embracing less 

 extended processes, and even a few in which chemistry finds 

 a limited application. Thus, the making of alum and glass, 

 the reduction of iron ores, the extraction and refining of sugar, 

 are all manufactures conducted on a vast scale. On the other 

 hand, phosphate of soda and chrome yellow are made on a 

 limited scale ; small quantities of nickel, of tannin, and per- 

 fuming oils, are extracted and refined ; and yet,, as their 

 preparation is wholly governed by chemical principles, these 

 processes belong to chemical technology. While some writers 

 incorrectly limit the subject to chemical manufactures, others 

 confine it to the first valuable products obtained. Thus, while 



the preparation of alum and copperas are acknowledged 



9 



