570 TRANSACTIONS OF THE 



18. Blue Martial Earth. — After exposure to the air for some 

 time, it becomes a deep blue, seldom of a smalt blue. Generally 

 found in bogs, sometimes in secondary stratified mountains^ 

 always some feet deep. Sometimes found white, or brown, or 

 green in its native beds; sometimes in large masses or lumps. 

 Heated on red hot coal it inflames and leaves a red powder which 

 is somewhat magnetic. Before a blow-pipe it instantly becomes 

 reddish brown, and melts into a black lead. 

 ■ 19. Green Martial Earth. — Light or dark canary green, passing 

 into olive green, or yellow. Friable, seldom indurated. It is 

 rare. 



20. Common Pyrites. — Color, bronze yellow, sometimes gold 

 yellow. 



21. Striated Pyrites. — Like the former when fresh broken, but 

 soon tarnishes, passing into variegations resembling the colors of 

 the peacock's tail. 



22. Capillary Pyrites. — Color, generally steel gray. Found 

 in hexangular or octangular acicular (sharp like prickles,) crys- 

 tals, either parallel or diverging from a common centre, or capil- 

 lary and woolly, or interwoven. 



23. Magnetic- Pyrites. — Color, between tombac brown and 

 brass yellow. Found disseminated and massive. 



24. Calcareous or Sparry Iron Ore. — Yellowish gray, passing 

 into yellowish brown. 



25. Cuhe Ore. — Color, olive green. 



ROLLING METALS. 



Rollers in common use are cast solid in cast iron chilling cylin- 

 ders, and thus the crystallization of the axle is rendered brittle 

 by the chilling process. To prevent this, Messrs. Stanley, Bel- 

 lamy & Booth, first cast the axle of tough metal, and when cold, 

 cast upon it a shell of harder metal, finer texture, as thick as re- 

 quired. The cold axle chills this outer coat. It may be cast in 

 the open sand. To prevent any fracture in the exterior coating, 

 the axle is made smaller in diameter in the middle — this figure 

 causes it to adapt the metal cast upon it without any fracture. 



The iron masters of England, are suffering from the effect pro- 

 duced in the United States — from their sending over here such 

 immense quantities of trash by the title of iron ! 



ULTRAMARINE. 



This splendid blue, hitherto very costly, is now manufactured 

 by tons weight, at the city of Nuremberg, in Bavaria. Messrs. 

 Zeltner and Heyne now have a factory of this color which covers 



