206 



crystallized like the matrix, and both homogeneous. They 

 were, when shut up here, solid enough to keep their mass 

 and yet fluid enough to crystallize most perfectly. Granite 

 was, indeed a most interesting subje6t of study. The two 

 projecting piers, of Rockport and Marblehead were granite 

 breakwaters, defending Boston Harbor from much of the 

 force of the terrible " northeasters." As a paving stone, 

 nothing was better than granite; trap indeed was, from the 

 nature of its fracture, better for macadamizing, but did not 

 wear as well for pavement. As a soil-maker, granite, espe- 

 cially the sienitic sorts produce better fruit than any other 

 formation ; the feldspar, when decayed, was a good fertil- 

 izer, as well as essential to the porcelain-maker. But the 

 great use of the granite is as a water-bearer. Nothing else 

 compares with it in this, as we at once see by comparing the 

 water of such a region with that of a limestone country^ 

 and the effect on the health of the people, observable in 

 either case. 



Stephen D. Poole of Lynn was sorry not to have more 

 time to examine the mineral treasures which the quarries 

 would evidently furnish. He had made some study of the 

 mineral spoken of by Mr. Alger. It was something like 

 lolite in appearance, but he believed it was Fluor Spar. 

 He had known Fkior to be mistaken on first sight before. 

 Some was found at Lynnfield a few years ago, and called 

 Amethyst, till chemical tests settled its real nature. 



Rev. E. B. Eddy of Portsmouth, N.H., had, as a miner- 

 alogist much enjoyed this day. These minerals were often 

 spoken of as mere stones, but they were real gems. There 

 should be more eyes and hands at work to save them. He 

 was told tliat to make the foundation of the breakwater 



