1883. 123 Trans. N. V. Ac. Set. 



■or more stories in height, in whose walls the crushing force exerted 

 aipon this soft stone must be excessive. 



6ea-sali in the atmosphere. — A comparison of the forms of decay of 

 -stone observed in the cemeteries within this city and in those nearer the 

 ocean, e.g., at New Utrecht, yielded no evidence of any results, attribut- 

 able to this agency, in greater action at the latter locality. Thus, too, in 

 England, the sandstone of Sandysfoot Castle, near Weymouth, which 

 has been washed by salt spray since the time of Henry VIII., remains 

 as perfect as ever. 



Heat of the i««.— There can be no doubt that this is one of the agen- 

 cies which most severely attack our brown-stone. On the cross 

 streets, the west sides of stoops become decayed and ragged, long 

 before the eastern ; so also the southern before the northern sides, 

 on our north and south avenues. The ashlar at the base of 

 the steeple of the church at 37th street and Fifth avenue is 

 beginning to decay on the south side, but not on the north or east 

 sides (the west side not being visible). The slender balusters of the 

 balustrades of balconies and along the sides of stoops are commonly 

 constructed of soft sandstone, with the lamination vertical and its plane 

 set irregularly, either parallel or at right angles to that of the house 

 front ; the ill-judged exposure of the soft stone in such a way has led 

 to the common mutilation of the carved work by exfoliation on the 

 side exposed to the sun, /. e., on the west side of the stoop-balustrades 

 in the cross streets, and on the south side along the avenues. 



Lichens.— It has been stated that th^se abound upon the brown-stone 

 within the city, but, though found upon trees, 1 have never discovered 

 them encrusting hewn stone within the city. Thus they never occur 

 in the churchyards of Trinity church and St. Paul's chapel, though 

 found abundantly in those of New Utrecht and Flatbush ; e.g., three 

 species were distinguished upon a single tombstone (Rutgert Denyse, 

 1795) at New Utrecht. On their removal, the surface of the stone 

 beneath is not found corroded, but only retains a fresh color. 



Imperfect pointing. — The admitted energetic agencies of decay — 

 frost, solution, hydration, etc. — have been largely favored by the im- 

 perfect and hasty construction of the masonry throughout the city, its 

 joints when new often admitting a trowel. A cement-mortar of 

 poor quality is largely employed and, soon dropping out, the joints are 

 often allowed to remain open for years. The atmospheric attack is 

 thus made, as it were in flank, directly through the exposed edges of 

 the outer laminae of the stone, and the decay rapidly affects the stone 

 to a considerable depth, several inches in many cases, and even through- 

 out the entire block, although the exfoliation may appear superficial. 



