232 



ARTILLERY 



An inspection of the first of the foregoing Tables, representing the average amount 

 of each foreign ingredient in gun-metal deduced from all the analyses, shows a con- 

 siderable difference in the proportions of those ingredients in each of the three classes 

 into which guns are divided. It will be observed, that while the proportion of com- 

 bined carbon diminishes from the 1st to the 3rd class, that of silicium similarly 

 increases, so that their united amounts are nearly the same. In other words, it 

 appears that silicium can replace the carbon to a certain extent ; but that the quality 

 of the metal is injured where the amount of the silicium approaches that of the oar- 

 bon. Karsten made a similar observation in determining the limits between cast-iron 

 and steel, but did not notice the influence of that substitution. 



But the differences become more striking by combining the ingredients variously 

 together, as in the second of those Tables ; and especially by comparing the extremes, 

 which are each derived from a larger number of observations than the mean. 



After showing the total amount of carbon (both combined and uncombined), sili- 

 cium and combined carbon are thrown together, which indicates the replacement by 

 eilicium of that portion of carbon set free in the form of graphite. The column ' sili- 

 cium and slag ' shows the general depreciation of the metal as the silicious metal 

 increases. From the "Report of Campbell Morfit and James C. Sooth to the Ordnawe 

 Office, United States' Army. 



The following analyses (rejecting those substances of which only a mere trace 

 has been discovered), from the same chemists, are selected as showing striking 

 peculiarities : 



Comparison of Weight, Strength, Extensibility, and Stiffness ; Cast-Iron being unity 

 ' wlhin practical limits to static forces only. 



We find that wrought-iron guns are more than fivefold as durable as those of 

 gun-metal, and twenty-two times as durable as those of cast-iron. And taking first 

 cost and durability together, gun-metal cannon are about seventy-seven times, and 

 cast-iron guns about thirty times, as dear as wrought-iron artillery. Again : the cost 

 of horse-labour, or other means of transport for equal strength (and, of course, there- 

 fore, for equal effective artillery power), is about five times as great for gun-metal, 

 and nearly three times as great for cast-iron as for wrought-iron guns. In every 

 respect in which we have submitted them to a comparison, searching and rigid, and 

 that seems to have omitted no important point of inquiry, wrought-iron stand! pre- 

 eminently superior to every other material for the fabrication of ordnance. United 

 States' Report. 



The advantages possessed by rolled bars for the construction of artillery are thus 

 summed up by Mr. Mallet, in his ' Memoir on Artillery : ' 



