Trans. N. Y. Ac. Set. 128 Apr. 30, 



LIMESTONE. 



The coarse fossiliferous stone from Lockport owes its rapid disinte- 

 gration within ten years, wherever used in this city, in part to its care- 

 less arrangement in masonry. Thus, in the building of the Lenox 

 Library, at 70th street and Fifth avenue, about 40 per cent of the 

 material is set on edge, e.g., the alternate recedmg courses of the ash- 

 lar, trimmings of apertures, gate-posts, etc. ; so also, in part, in the 

 stone used in the Presbyterian Hospital. The oolitic stone from Ellits- 

 ville, Indiana, shows an almost immediate and irregular discoloration, 

 said to be produced by the exudation of oil. The oolite from Caen, 

 France, has also been used in many buildings, and, unless protected 

 by a coating of paint, has shown decay in several instances. Mr. G. 

 Godwin, of London, has stated (Soc. of Arts, 1881,) that "the 

 Caen stone which was sent to this country (England) could not now 

 be depended on and ought not to be used for external work." The 

 extensive decay of this, with other oolitic and magnesian limestones, in 

 the walls of Westminster Abbey, has recently caused great alarm and 

 will necessitate the renewal of its outer masonry at enormous expense. 



One of the most thorough investigations, in regard to the porosity of 

 a series of American building-stones, was made by Dr. T. S. Hunt in 

 1864, and with the following conclusion (Chem. and Geol. Essays, p- 

 164): 



" Other things being equal, it may probably be said that the value of 

 a stone for building purposes is inversely as its porosity or absorbing 

 power." From the results given on 39 specimens, the following may 

 be here quoted as pertinent to stones used m New York City : 



No. of Specimens. Absorption Percentage. 



1. Potsdam sandstone, hard and white. 0.50 — 3.96 (usually about i) 



2. Medina sandstone 3.31 — 4.04 



3. Ohio sandstone 9.59 — 10.22 



3. Caen limestone 14 48 — 16.05 



Of course the proviso, " other things being equal," covers a great 

 deal of important ground, including the solvency of the material of a 

 stone in the acidified rain-waters of a city. Some of the most im- 

 pervious and non-absorbent readily decompose ; while others, which 

 are porous or even cellular, may afford an excellent resistance to 

 decay. But judged in regard to both points, porosity and solvency, 

 the Caen stone may be safely rejected hereafter as unfit for our 

 climate. 



MARBLE. 



The dolomitic marble of Westchester County has been largely em- 

 ployed in our buildings, and some idea of its character for durability 

 may now be gained. A fine-grained variety was used in the building 



