involved in the Construction of Artillery. 



367 



portions of the alkaline and earthy metals produce a greater deterioration in those qualities 

 than any other foreign additions. The presence of these last is the peculiar characteristic 

 of hot-blast iron, arising simply from the extreme elevation of temperature of the furnace. 

 Ho-w little the proportion of sulphur depends alone upon fuel, &c., and how nearly it 

 is alike, or may become so, with any fuel, may be seen from the following analyses of 

 American cast and wrought-iron, made by M. Svanberg ("Jour, fur Prac. Chem." h. xl., 

 p. 232):— 



American Cast-Irons. 



a, From Juanita ; h, from Longmine, Orange County, New York State ; c, Salisbury 

 iron (that of which the Princeton gun is stated to have been forged), Connecticut; 

 d, Missouri; c. Anthracite iron of Columbia, Denville County; /, Iron of the Lc High 

 Company : — 



American Wrought-Irons. 



It is much to be regretted that these latter analyses give the carbon only by the loss. 

 a, Is Juanita iron; b, Longmine; e, Salisbury; d, Missouri; e, Nail-rods, or slit-bars. 

 The relative strengths of several of these makes of iron are given in the Table, section 

 210, text. 



In comparing these Tables of tenacity of American irons, and more especially the 

 results given in the volume of "United States Ordnance Keports," recently published by 

 Triibner, London, with the admitted standards of tenacity of British irons, mainly due to 

 the laborious, valuable, and almost life-long researches of Hodgkinson, — this must be 

 distinctly borne in mind — that the American experiments are made chiefly upon mottled 

 gray iron, carefully prepared, as the toughest and most tenacious procurable by mixtxtre or 



3b2 



