170 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



good quality that an examination of its composition was un- 

 dertaken, which resulted in showing that it was almost abso- 

 lutely pure tin, containing less than three per cent, of foreign 

 substances (lead and iron). It was found to be impossible 

 to reunite by fusion the metal so curiously divided, for, in 

 the attempt, it gave rise to such a quantity of oxide of tin 

 that the product was nothing better than a gray powder. 

 The explanation offered to account for this case is that the 

 disaggregation of the metal was the result of the combined 

 influences of cold and vibration. It should, however, be said 

 that the phenomenon is by no means an exceptional or iso- 

 lated one, several analogous cases having been quite recent- 

 ly reported. The explanation above suggested seems, in the 

 absence of a thorough investigation, to be at least reason- 

 able, and places the case in the same category with the mo- 

 lecular changes which are frequently known to occur with 

 other metals when exposed to long-continued vibration. 



CRYSTALLINE STRUCTURE PRODUCED BY CONCUSSION. 



Professor Thurston, in his researches on the behavior of 

 metals under strain, presents the following statements con- 

 cerning the physical texture of metals and its relation to 

 predicable causes. A kind of fracture which is probably al- 

 ways indicative of brittleness is generally, and possibly cor- 

 rectly, termed crystalline. It is supposed to be caused by 

 a long-continued succession of shocks, which, straining the 

 metal to the elastic limit, permit the crystalline grouping of 

 the molecules to take place. Dr. Percy, one of the leading 

 metallurgists of the world, seems to have been fully con- 

 vinced of the possibility of the formation of true crystals in 

 this way ; but direct experiment is still desirable fully to de- 

 termine it. Professor Thurston then details the following 

 striking, though accidental, occurrence, which affords, in the 

 most satisfactory manner, the experimental verification de- 

 sired : A singular instance of this peculiar molecular action 

 recently occurred at the Morgan Iron Works in New York. 

 While a powerful steam-hammer was at work upon the red- 

 hot end of a shaft, originally designed for the engines of a 

 large naval steamer, a piece of the opposite end, which was 

 cold, and which was supposed to be strong enough to trans- 

 mit several thousand horse-power, dropped off. This was an 



