400 



SCIENTIFIC RECREATIONS. 



metal itself, and in the air used. When the flame issuing from the 

 " converter" contracts and changes its colour, then the time is known to 

 have arrived when the iron is " de-carbonized." The amount of carbon 

 necessary is artificially added, ebullition takes place, a flame of carbonic 

 oxide comes out, and the metal is then run into ingots. 



The compounds of iron which are soluble in water have a peculiar 

 taste called chalybeate (like ink). Many mineral springs are so flavoured, and 

 taste, as the immortal Samuel Weller put it, "like warm flat-irons." Iron is 

 frequently used as a medicine to renew the blood globules. 



Protoxide of Iron is known only in combination. 



Sesqtd-Oxide of Iron is "red ironstone." Powdered it is called 

 English rouge, a pigment not altogether foreign to our use. In a pure state 

 it is a remedy for arsenical poisoning, and is really the " rust " upon iron. 



Fig. 410. Bessemer's process. 



Bisulphide of Iron is iron pyrites, and is crystalline. 



Chloride of Iron is dissolved from iron with hydrochloric acid. It is 

 used in medicine. 



Cyanide of Iron makes, with cyanide of potassium, the well-known 

 prussiate of potash (ferro-cyanide of potassium), which, when heated, pre- 

 cipitates Prussian blue (cyanogen and iron). 



The Sulphate of the Protoxide is known as copperas, or green vitriol, and 

 is applied to the preparation of Prussian blue. 



MANGANESE is found extensively, but not in any large quantities, irr 

 one place ; iron ore contains it. It is very hard to fuse, and is easily 

 oxidised. The binoxide is used to obtain oxygen, and when treated with 



