1874.] Crystalline Structure of Wrought Iron. 73 



5. (Broken) and the second hemistich is unintelligible.) 



6. He built this edifice from the taxes of his kingdom. God will give him an 

 emerald castle in Paradise. 



7. Know that the date is the 9th Jumada I, 732 [7th February, 1332.] 



Col. Hyde exhibited two specimens of iron as remarkable examples of 

 the change that takes place in the structure of wrought iron when submitted 

 to long and continued concussion or strain, and he explained that the first 

 section was one face of the fracture of the piston-rod of a steam-hammer, 

 "^hat had been in use some seven years. 



The rod, which was 5'^ in diameter, broke off suddenly while the ham- 

 mer was at work. The fracture is sharp and perfectly crystalline in many 

 places exhibiting faces, measuring ^ of an inch. 



The other face of the fracture, which he also placed on the table, had 

 been heated and cut, so as to prepare the rod for the new end to be welded 

 on, and from it would be seen that this operation had, when the hammer 

 had been applied, entirely restored the original structure of the iron. 



The second example was a small piece from the fracture of one of the 

 rods of an hydraulic press that had been at work for some 25 years in a 

 bullet machine, and its structure was even more remarkably crystalline than 

 that of the steam-hammer piston. 



Col. Hyde remarked that though it was perfectly well known that 

 concussion and vibration produced this change in the structure of iron (a 

 fact of which they had daily experience in the Mint machinery), he was not 

 aware if it was well established, that the same change was produced by the 

 gradual forces at work in iron in the position of a rod in an hydraulic press, 

 and that in the two examples on the table, the same result had been produced 

 in one by repeated and violent concussion end on for some seven years ; in 

 the other by repeated but gradual tension end on for some twenty-five 

 years. 



Mr. Schwendler remarked that the two pieces of crystallized wrought 

 iron exhibited by the President were most perfect specimens, and added that 

 it would be interesting to know if this crystalline state of the iron super- 

 venes suddenly or is only arrived at gradually, he himself was inclined to be- 

 lieve the former to be the case, since it can scarcely be admitted that there 

 is any intermediate state between the amorphous and the crystalline condi- 

 tion of the same body. 



Dr. Waldie could not concur with Mr. Schwendler inasmuch as there 

 were many gradations between the non-crystalline and crystalline states of 

 bodies, and that pieces of wrought iron which had been subjected for differ- 

 ent lengths of time to crystallizing influences exhibited different degrees of 

 crystallization. 



