Conversion of Cannon Balls into Plumbago. 179 
iustre—the same crystaline grain, and the same semi unctuosi- 
ty when rubbed between the fingers. It gives the same streak 
on paper, and when rubbed on leather or on cast iron, it 
produces the same lustre, and it polishes and sharpens steel 
instruments just like plumbago. No one could by the éye 
distinguish them. The magnet, however, takes up this 
substance readily, while it produces no effect on black lead. 
This substance is not altered by the blowpipe, only it grows 
firmer. The cannon ball, by lying three days in a dry room, 
where there is a fire, has grown less soft, but retains all the 
other properties. Where it has been cut or powdered, it 
rusts, superficially, in the course of a day or two. 
Is the change in this ball to be attributed to a substitu- 
tion of carbon derived from the vegetable matter of the salt 
marsh for a part of the iron—the carbon combining with the 
remainder of the iron? The substance is only partially so- 
luble in diluted. sulphuric acid—hydrogen is evolved, and a 
black insoluble matter remains, which appears to be carbon. 
Since this occurrence has been talked of in New-Haven, 
an old gentleman, resident here, mentions a similar instance, 
as having occurred within his observation; acannon ball, long 
immersed.in salt water, and covered with shells, was found 
to have undergone a similar change. We are not aware that 
ihe occurrence has been mentioned elsewhere. 
New-Haven, Oct. 17, 1821. 
P.S. Since the above notice was written, we have ob- 
iained from Capt. Daniel Goffe Phipps, of New-Haven, the 
person alluded to above, the following statement. 
Capt. Phipps. was in Georgia about twenty years ago, and 
being in a boat, at a place called Rumley Marsh, visited 
the wreck of a vessel, which lay principally in the mud, but 
with the ribs protruding into view. From this wreck he 
took a very large bunch of oysters, which adhered to a six 
pound cannon ball, and this lay on what had probably been 
the ballast of the vessel; it was not only under water, but 
probably buried in mud, and the vessel’s wreck appeared as 
if it had been there many years. ‘The oysters were knock- 
ed off, and the ball, by rolling about the deck of the vessel 
to which Capt. Phipps belonged, had become smooth and 
clean. The oysters had adhered to the ball at only one 
place ; this place which was about two inches in diameter, 
