SANDSTONES. 361 



quartz, limestone, etc., and they are named according!) gran 

 ztic, quartzose, calcareous, conglomerates. 



The use of sandstone as a building material is well known. 

 For this purpose it should be free, like granite, from pyrites 

 or iron sand, as these rust and disfigure the structure. It 

 should be firm in texture, and not liable to peel off on ex- . 

 posure. Some sandstones, especially certain argillaceous 

 varieties, which appear well in the quarry, when exposed for 

 a season where they will be left to dry, gradually fall te 

 pieces. The same rock answers well for structures beneath 

 water, that is worth nothing for buildings. Other sandstones 

 which are so soft as to be easily cut from their bed without 

 blasting, harden on exposure, (owing to the hardening of 

 silica in the contained moisture,) and are quite durable. 

 These are qualities which must be tested before a stone 

 is used. Moreover it should be considered that in frosty 

 climates, a weak absorbent stone is liable to be destroyed in 

 a comparatively short time, while in a climate like that of 

 Peru, even sunburnt bricks will last for centuries. 



Mr. Ure observes, that " such was the care of the ancients 

 to provide strong and durable materials for their public edi- 

 fices, that but for the desolating hands of modern barbarians, 

 in peace and in war, most of the temples and other public 

 monuments of Greece and Rome would have remained 

 perfect at the present day, uninjured by the elements during 

 2000 years. The contrast in this respect of the works of 

 modern architects, especially in Great Britain, [much more 

 true of the United States,] is very humiliating to those who 

 boast so loudly of social advancement ; for there is scarcely 

 a public building of recent date which will be in existence 

 a thousand years hence." Many splendid structures are 

 monuments (not endless) of folly in this respect. He ob- 

 berves also that the stone intended for a durable edifice ought 

 to be tested as to its durability by immersion in a saturated 

 solution of sulphate of soda, and exposure to the air for some 

 days : the crystallization within the stone will cause the same 

 disintegration that would result in time from frost. 



The dark red sandstone (freestone) of New Jersey and 

 Connecticut, when of fine gritty texture and compact, is gen- 

 erally an excellent building material. Tiinity Church in 

 New York is built of the stone from Belvilie, New Jersey. 

 At Chatham, on the Connecticut, is a large quarry, which 

 supplies great quantities of stone to the cities of the coast ; 



