involved in the Construction of Artillery. 369 



The furnace of Konigshutte ia fed with beech; that of Leerbach with fir fuel. 



The analyses are by Bodemann (" Pogg. Anal." t. Iv., p. 485). Sulphur was present 

 in every instance ; and had the amount of the earthy and alkaline metals admitted uf esti- 

 mation, they would have shown, doubtless, some preponderance in the case of hot-blast 

 with wood as with coal fuel, from the higher temperature of the furnace. 



The molecular condition of the carbon in the pig-iron — -the proportion in which it is 

 developed as graphite, and in which it is in combination chemically with the iron — seem 

 also much dependent upon temperature, as well as the magnitude of the individual crystal- 

 line scales of graphite, tipon whicli, more than upon any other condition, the tenacity of 

 cast-iron aj^pears to depend; it being obvious that in mixed irons, constituted like the coarse 

 masses of which some of the Baltic mortars, referred to in a previous Note, consisted, 

 the strength of any given section is limited to the strength of that portion of the whole retictda- 

 iion which is solid iron, since the nests of crystalline graphite are almost devoid of cohesive 

 resistance, and may be absolutely deducted, quoad ultimate tensile stretigth. 



Upon this part of the subject the following authors or papers may be consulted with 

 advantage: — Karsten ("Ann. derChem. und Pharm.," Ix., p. 2'dO), on the "Constitution of 

 the Spiegeleisen," in which the whole of the carbon is in combination, and which contains 

 from 4-28 up to the enormous proportion of 5-723 per cent, of carbon ; its colour bright and 

 silvery, with intense hardness, and breaking into huge, fully developed rhomboidal crys- 

 tals, often two or three inches long, as figured in Plate v., Fig. 3, text. 



Berzelius "On the AUotropic Modifications of the Simple Bodies." (" Jahresbericht,' 

 1844, p. 18.) 



Sandberger " On Carbon developed in large hexagonal Tables in the Slags of the Iron 

 Work of Dillenberg, Nassau." (Liebig & Kopp, "Jahresbericht," 1851, p. 151.) 



Schafheautl, various papers in " Phil. Maga.," London ; and " Pogg. Ann." on same 

 subject. 



Laurent, " Ann. de Chim.," t. Ixv., p. 417. 



Le Play, " Mem. on the Manufacture of Steel," " Ann. des Mines," tt. iii. & ix. 4ie ser. 



Engelhardt, " On Tubercular Masses of Carbon, formed (apparently from a volatile 

 state) within the Masonry of the Blast Furnace of Niederbronn, Lower Rhine." (" Ann. 

 des Mines," 4 ser., t. iv., p. 429.) 



Plate V. (next page) is inserted out of its proper place, not having been received from 

 the lithographer in time, in consequence of unavoidable delays in procuring the speci- 

 mens and taking photographs of them, from both of which the very faithful figures of the 

 Plate have been prepared. 



