58 . Economical Geology. 



borough, and another in Walpole ; and two blast furnaces and four air 

 furnaces, in Chelmsford. In these he employs not far from five hun- 

 dred men. He generally mixes the different sorts of ore, or at least, 

 two or three of them together for smelting. Extensive iron works 

 are also carried on in Wareham. Several furnaces exist in Berk- 

 shire, and a few in Worcester county. 



The preceding view of our deposits of iron, demonstrates that we 

 abound in this useful metal, and that the demand for centuries to come, 

 cannot exhaust it. 



Ochres, fyc. used as paints. 



There are two kinds of ochre, the red and the yellow, which are 

 merely pulverulent varieties of the red and brown oxide of iron. The 

 yellow ochre is abundant with our haematite and argillaceous ores, 

 and is frequently employed as a pigment. According to Mr. C. T. 

 Jackson, red ochre occurs in Eoylston in a bed four or five inches 

 thick, mixed with clay. It has already been mentioned, that the earthy 

 phosphate of iron in Hopkinton, is employed as a blue paint. Prof. 

 Dewey mentions that a yellow earth is found in Williamstown, from 

 which great quantities of yellow ochre are obtained by washing. Dr. 

 J. Porter states, that yellow earth occurs in Monroe, which, when 

 purified, affords a "pale red paint." The process of preparing it he 

 says is now suspended for want of a demand. 



Lead. 



Several ores of this metal are enumerated by mineralogists, as oc- 

 curring in Massachusetts ; but none is found m sufficient quantity 

 to render it of any statistical interest, except the sulphuret, commonly 

 called galena ; and all the important veins of this species are confint- 

 ed to the vicinity of the Connecticut river. No fewer than thirteen 

 of these occur in that region of sufficient importance to deserve notice. 

 All these are in mica slate or granite ; or they pass from the one 

 rock into the other. 



In Southampton. 



The vein in the northern part of this town has attracted more atten- 

 tion than any other in the region, and has been several times de- 

 scribed. It is six or eight feet wide, where it has been explored, and 

 traverses granite and mica slate, the matrix or gangue containing the 

 ore, being a mixture of quartz and sulphate of barytes. It has been 



