37 



phy. The minute accuracy of modern chemical analy- 

 sis has made us intimately acquainted with the actual 

 composition of most of the bodies upon which we 

 have occasion to operate. Upon this accurate know- 

 ledge of the chemical constitution of bodies was 

 founded the discovery of the uniform combination 

 of the constituents of compounds in definite propor- 

 tions, and the construction of the tables of chemical 

 equivalents; a discovery which introduced a degree of 

 certainty in carrying on the thousand arts dependent 

 upon chemical action, which could not have been 

 attained by experience and observation alone, how- 

 ever skilfully conducted. The chemical manufac- 

 turer who is ignorant of this discovery, or does not 

 apply it in the prosecution of his art, is like a ma- 

 riner at sea without compass or quadrant. 



I cannot forbear to notice here three very recent 

 and valuable discoveries in the application of science 

 to the useful arts, each of which is of a very striking 

 character. I mean the daguerrotype, the electro- 

 type, and the electro-magnetic telegraph. By the 

 former, we are supplied with pictures of the works 

 of nature and of art, imprinted by the rays of light 

 with a minute accuracy that cannot be attained by 

 the best directed pencil in the hands of the artist. 

 By the second, medals, engravings, sculptures, and 

 many other works of art, may be multiplied to an in- 

 definite extent, and with perfect faithfulness, by a 

 process the most simple. To what extent this elec- 

 tric action upon metallic solutions may be carried, it 

 is impossible to foresee; but it has been recently ap- 

 plied to the gilding of metals, and is likely to super- 



