Trajis. N. V. Ac. Set. 130 ^/^- 30. 



The stones of a coarse tremolitic dolomyte-marble date from 1847 

 back to 1 81 8. They weather grayish and become much roughened 

 over the east face, top and sides, and sometimes over a third of the sur- 

 face down the west face. Fissures in the edges of the stone begin 

 after about 30 years exposure. The polish has survived for about 40 

 years on the faces of some stones of this class, even when the edges 

 are disintegrated. Near the ground for a foot the polish remains even 

 much longer, e.g., the double stone of Femetie and Peter Stryker 



(1730)- 



St. Paul's Churchyard. — The stones here date from 1851 back to 

 1798, and consist of a coarse white marble. It weathers grayish white, 

 and becomes roughened. Only a small proportion of the stones are 

 split. About one-tenth have their inscriptions entirely obliterated, and 

 this fact, due doubtless to the acid rain-waters of the city, was not ob- 

 served in the suburban cemeteries; in one case (A. W., 1851) it has 

 been largely affected in a little over 30 years. 



The horizontal tablets, supported on masonry, which has partially 

 settled {e.g., J. G., 1821), generally show a slight curvature in centre, 

 only in part possibly produced through solution by standing rain- 

 water. 



Dolomieu first made the observation on an Italian marble called 

 Betullio, that it possessed a degree of flexibility allied to that of the 

 itacolumyte of Brazil. Gwilt states (Encyc. of Arch., p. 1274) '• 



" Some extremely fine specimens of white marble are to be seen in 

 the Borghese Palace at Rome, which, on being suspended by the centre 

 on a hard body, bend very considerably. It is found that statuary 

 marble exposed to the sun acquires, in time, this property, thus indi- 

 cating a less degree of adhesion of its parts than it naturally pos- 

 sessed." 



In the white marble- veneenng of the facade of St. Marks, Venice, the 

 same effect has been observed by Mr. C. M. Burns, Jr., in the lower 

 halt of a slab of veined marble, two inches inick, on the south side of 

 the northernmost of the five portals, just behind the columns and about 

 five feet from the pavement. The slab is eleven feet and two inches 

 long, and one foot and six inches wide ; it is hung to the backing by 

 copper hooks driven into the brickwork, but the lower part, for a dis- 

 tance of five feet and seven inches, bulges out two and three-quarter 

 inches from the backing. "The exposure is directly westward, and I 

 found that it became decidedly warm in the afternoon sun, while the 

 backing would be likely to keep its temperature lower. Though the 

 outer surface is somewhat weatherworn, I could not find the slightest 



