322 PROCEEDINGS OF THE AMERICAN ACADEMY 



Four huntlred and thirty-first meeting. 



October 14, 1856. — Monthly Meeting. 



The President in the chair. 



Dr. C. T. Jackson, from the committee appointed at the last 

 preceding meeting to consider the propriety and practicability 

 of removing Dighton Rock, read a letter from Dr. Hamlin of 

 Maine, describing the present sitnation of this interesting an- 

 tiquity, and giving urgent reasons for its removal, in order to 

 the preservation of the inscription, which, it appears, is in 

 such a position that it cannot well be photographed as it 

 lies. 



President Hitchcock joined in the recommendation, and 

 gave some details respecting the position and nature of the 

 rock, and the condition of the inscription, which, he argued, is 

 likely soon to be obliterated, unless removed from its present 

 situation. 



Dr. O. W. Holmes exhibited a suite of Indian arrow-heads, 

 or, most likely, spear-heads, found in the soil of his grounds 

 at Pittsfield, arranged in a series so as to show all the stages 

 of manufacture, from the natural piece of hornstone, slightly 

 hammered, to the finished implement. 



Dr. A. A. Hayes made the following communication : — 



" On the Change of Position among the Particles of Solid 

 Metals, induced hy the Action of Gentle hut Continued Per- 

 cussion of the Masses they form. 



" In calling the attention of the members to this subject, I will 

 state that the chief illustration of some new points is to be found in 

 the specimens exhibited ; which show the gradation of action, depend- 

 ent on time elapsing while the masses were exposed, in a distinct 

 manner. 



" The change by which malleable iron becomes converted into a 

 highly crystalline metal, when subjected to pressure attended by a 

 tremulous motion, as in the case of railway bars, has been often 

 observed, and the attendant circumstances noted. My attention has 

 been called to many cases, in which the same effects have followed 



