POPULAR MISCELLANY. 



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POPULAR MISCELLANY. 



Durability of Building - Stones. Dr. 



Alexis A. Julien has made examinations of 

 buildings of various ages, and of tombstones 

 in some of the older grave-yards around 

 New York city, to assist in determining the 

 durability of the various stones used in 

 building. The coarse brown-stone, which 

 is largely employed, appears to be one of 

 the most perishable materials in use, so 

 that many builders are returning to brick, 

 although the finer varieties of brown-stone 

 are better and compare favorably with other 

 materials. Among the causes for the decay 

 of this stone are mentioned, erection on 

 the edge of lamination, the heat of the 

 sun on exposed sides, and imperfect point- 

 ing, with poor mortar, which falls away 

 and leaves the joints exposed to the 

 weather. The presence of sea-salt in the 

 atmosphere has exerted no appreciable ef- 

 fect, and lichens growing on the stone do 

 not appear to have occasioned any decay or 

 corrosion. The light-colored Nova Scotia 

 sandstones have been too recently intro- 

 duced to show marked defect, but evidences 

 of exfoliation and of slight moldeiing in 

 damp spots have begun to appear. Build- 

 ings constructed of the Amherst (Ohio) sand- 

 stone show little decay, only discoloration ; 

 and that is regarded as a favorable sign 

 rather than otherwise, for it indicates dura- 

 bility, while a stone that cleans itself does 

 so by disintegration of its surface, the 

 grains dropping out and carrying away the 

 dirt. The coarse fossiliferous limestone 

 from Lockport has disintegrated rapidly 

 within the last ten years, chiefly on account 

 of careless arrangement in masonry. The 

 oolitic stone from Ellettsville, Indiana, shows 

 an almost immediate and irregular discolor- 

 ation, said to be produced by the exudation 

 of oil. The oolite from Caen, France, has 

 shown decay in several instances where it 

 was not protected by paint. The dolomitic 

 marble of Westchester County has decayed 

 considerably after sixty years of use, but 

 much of this is owing to the stone having 

 been improperly laid. Often marbles, of 

 various kinds, in tombstones, are in fairly 

 good condition. Horizontal slabs show a 

 tendency to bend. The frequent oblitera- 

 tion of inscriptions, the general and often 



rapid granulation of the surface, and the 

 occasional Assuring of slabs, show that the 

 decay of marble in the varieties hitherto 

 long used in New York city is steady, in- 

 evitable, and but a question of time ; and, 

 if unprotected, this material is likely to 

 prove utterly unsuitable for out-of-door use, 

 at least for decorative purposes or cemete- 

 ry records, within the atmosphere of a city. 

 A blue-stone, or graywacke, is yearly com- 

 ing into more general use, and, though some- 

 what somber in tone and difficult to dress, 

 seems likely to prove a material of remark- 

 able durability. The bluish Quincy granite 

 has been used in many buildings, and rarely 

 shows as yet many signs of decay. A fine- 

 grained granite from Concord, New Hamp- 

 shire, also promises to be durable. The 

 light-colored and fine-grained granite of Hal- 

 lowell, Maine, in which the white feldspar 

 predominates, has shown some exfoliation, 

 but in the single building in which this is 

 remarked the stones appear to have been 

 set on edge, and, as their structure is lami- 

 nated, that is an important matter. u The 

 weathering of granite does not proceed by 

 a merely superficial wear, which can be 

 measured or limited by fractions of an inch, 

 but by a deep insinuation along the lines 

 of weakness, between grains, through cleav- 

 age-planes, and into latent fissures. Thus, 

 long before the surface has become much 

 corroded or removed, a deep disintegration 

 has taken place by which large fragments 

 are ready for separation by frost, from the 

 edges and angles of a block. When directly 

 exposed to the heat of the sun, an addi- 

 tional agency of destruction is involved, 

 and the stone is suddenly found ready to 

 exfoliate, layer after layer, concentrical- 

 ly." The following is an approximative 

 estimate of the "life" of different kinds 

 of stone, signifying by the term life, without 

 regard to discoloration or other objectiona- 

 ble qualities, merely the period after which 

 the incipient decay of the variety becomes 

 sufficiently offensive to the eye to demand 

 repair or renewal : coarse brown-stone, five 

 to fifteen years ; laminated fine brown-stone, 

 twenty to fifty years ; compact fine brown- 

 stone, one hundred to two hundred years ; 

 blue-stone, untried, probably centuries; Nova 

 Scotia stone, untried, perhaps fifty to two 

 hundred years ; Ohio sandstone (best sili- 



