Dr, Cutbush on the Chinese Fire, 4rc. 123 



lure of the several sorts, or modifications of iron. In the 

 white, grey, and black crude iron (the best of which for fire 

 works are the two first) carbon and oxygen, with occasion- 

 ally other substances, as silicium, &c. are differently com- 

 bined ; which, when made into malleable iron, loses from 

 one fourth to sometimes one half of its weight. 



According to Mr. Cloud, the quantity of carbon in cast 

 iron is equal to ^th of the whole weight, and M. Vauque- 

 lin gives the average quantity in steel at xi o^h part, which 

 differs, however, from the experiments of Mr. Mushet. 

 Without considering the presence of oxygen, &tc. in cast 

 iron, or its agency when combined in a certain proportion 

 with iron, we may infer from this statement that crude iron 

 owes its superiority for fire works to its containing a larger 

 quantity of carbon. 



The experiments of M. M. Berzelius and Stromeyer, by 

 which they produced a compound of iron, carbon, and si- 

 licium ; of Mr. Daniell on grey cast iron, which he found to 

 contain iron, oxide of iron, carbon, and silicium ; of Ber- 

 zelius, who proved the presence of magnesium and manga- 

 nese, besides carbon and silicium in pure cast ir^-n ; of 

 Mushet, who has shown the proportion of carbon in the 

 different carburets of iron ; and of Bergman and others on 

 the existence of siderite, (phosphate, by some a phosphuret 

 of iron) distinguishing thereby the cold-short and red short 

 iron, are all useful in pointing out the composition, as well 

 as the proportion of the substances, which constitute the 

 so called carburets of iron. Mr. Mushet has shown that 

 soft cast steel contains rloth of carbon, common cast steel 

 ^i^th, the harder common cast-steel gVth, and when the 

 quantity of carbon is sV^h, steel is then too hard for draw- 

 ing ; and that white cast iron contains -^-^ih, the mottled 

 cast iron gVth, and black cast iron ^j\h. It is found, that 

 when the carbon amounts to -j^^^tli of the whole, th^ hard- 

 ness is at a maximum. In wootz, or Indian steel, there is 

 a small quantity of aluminum and silicium. Mr. Danfell 

 (^Quar. Jour. Science and Arts, ii. 280) observes, that white 

 cast iron is acted upon but ^lowly by acids, and exhibits a 

 texture composed of a congeries of plates, variously aggre- 

 gated ; and that the grey or mottled iron, which is softer 

 and less brittle, and readily bored and turned, affords, when 



