18 



rational processes are given.''' Arts and manufactures are passing 

 more and more from the empirical to the scientific state, and to 

 appreciate the immeasurable improvement that takes place when 

 a manufacture is based on a rational foundation and not on mere 

 empiricism and what is called familiarly " rule of thumb," a com- 

 parison may be made, say of Canepario's account of sulphuric acid 

 making with the treatise by Lunge on the same subject, or the 

 tiny chapters on iron smelting in Agricola or Ercker, with 

 Lowthian-Bell's Studies of Blast Furnace Phenomena or Percy's 

 Treatise on Iron. ^ 



On another occasion I hope to communicate to the Society ex- 

 tracts from some of the books now exhibited, and to supplement 

 the list with notes on other works of a similar kind, which I have 

 not in the meantime at hand. 



Postscript.— \ have just become aware of the existence of a 

 " History of Inventions," by F. S. White ; but of the book I, as yet, 

 know nothing. 



* One still more recent is now to be had. Its title is " Spoil's Encydo- 

 pcedla of Industrial Arts, Manufactures, and Baio Commercial Products." 

 and it has just been published in London in two volumes. The author, 

 editor, publisher, or whoever is responsible for the advertisement of it, 

 makes a special merit of its containing a minunum of scientific and his- 

 torical details. 



