Mr. J. Taylor's Lectures on Metallurgy. 291 



imparting to it a variety of delicate and transparent colours, 

 which are used in the arts above mentioned : 



Oxide of gold fine purple. 



Oxide of iron common reds. 



silver, lead and antimony ... yellow. 



copper, chrome green. 



cobalt fine blue. 



manganese violet. 



tin white. 



The fabrication of imitative gems is dependent on the same 

 circumstances ; and the colour of real gems may also be attri- 

 buted to metallic mixtures. 



Another numerous class of substances originating from the 

 affinity of metals with other substances, are the Metallic Salts, 

 generally resulting from the combination of metals and acids. 



The list, if completely detailed, would extend to a great 

 length. The following are some of those most commonly em- 

 ployed in the arts. 



Carbonates of lead ... white lead. 



copper ... verditer. 



Sulphates copper ... Roman vitriol. 



ii-on ... green vitriol, copperas. 



zinc ... white A'itriol, 



Nitrates silver ... lunar caustic. 



Muriates mercury ... calomel & corrosive sublimate 



tin ... salJovis — used in solution in 



Acetates copper ... verdigris. [dyeing. 

 ! iron ... iron liquor. 



lead . . . sugar of lead. 



Prussiates iron ... Prussian blue. 



Gallates iron ... ink, black dyes. 



. What has been said on the various uses of the metals, on 

 the different apphcations of which their properties render them 

 susceptible, and of the curious changes which they undergo — is 

 perhaps sufficient to cause us to reflect on the important place 

 they hold among the gifts of Providence to man ; and it would 

 be an interesting inquiry to follow up the operations in detail, 

 of which an outline has been given. 



[To be continued.] 



O o2 



LXV. No- 



