10 CHEMICAL TECHXOLOGY. 



chemical arts and manufactures, their extensive application to 

 organic fibre to give permanency to dyes, and the whole art 

 of dyeing and calico-printing, would be excluded. This is 

 manifestly wrong, if the definition of the arts which we have 

 given be correct ; and we cannot exclude those arts of a chemi- 

 cal nature, which more immediately flow from any one branch 

 of manufacture, especially when we consider that such col- 

 lateral arts are often necessary to the economy of a particular 

 branch of manufacture. 



Emanating from chemistry, chemical technology has been 

 usually treated as a branch of that science, and has been cor- 

 rectly designated " applied chemistry." Its recent expansion, 

 however, by the aid of chemistry, allows of its establishment 

 as an independent branch of knowledge, — a science, capable 

 of a classification, not on the principles of chemical science, 

 but evolved from itself, by a comparison of its subjects with 

 each other. The main principle which should govern such 

 classification is the object in view or the product to be made, 

 and, with this, the secondary arts necessarily or usually con- 

 nected with it. Thus, the making of soap, being an important 

 art, and an extensive manufacture, necessarily includes the 

 extraction and purification of oils and fats, while perfumery 

 and chandlery seem to follow in its train in a natural order. 

 Th-e following is an attempt at such a classification of the 

 subjects in chemical technology, and is the result of some 

 years' experience in lectures on the chemical arts, delivered 

 by the writer before the Franklin Institute of Philadelphia. 

 Doubtless, it will be found imperfect, but it is fair to offer as 

 an apology, the difiiculty experienced by the chemist in separat- 

 ing in his mind the composition and properties of bodies from 

 their connection as objects of manufacture, and in break- 

 ing down long-cherished associations of purely chemical 

 characteristics. 



Chemical affinity may be regarded as the force employed in 

 the chemical arts; fuel and water, as the principal agents used 

 to modify or direct this force ; and the crude productions of 

 the mineral, vegetable, and animal kingdoms, as the materials 



