372 BULLETIN OF THE NEW YORK STATE MUSEUM 



tests, are not such as to be resisted equally well by all varie- 

 ties of sandstone, as has been shown in the above notes of 

 the results. And, hence, comparatively few can be found 

 which are durable under ordinary exposure to atmospheric 

 agencies, and are fire-resisting, also. The importance of dura- 

 bility under ordinary conditions is evident at once, and out- 

 ranks, in all general constructive work, that of fire-resist- 

 ance, which may be viewed as extraordinary exposure or an 

 accidental condition. The superiority of the better sand- 

 stones to the granites, marbles and limestones in their prop- 

 erty of resisting the effects of high temperature — fire — is 

 notable and worthy of consideration, and these latter classes 

 of stone are shown by the tests to be unable to with- 

 stand the vitrifying and calcining effects of intense heat. 

 Under ordinary weather exposure, as shown by the freezing 

 and thawing tests, they are quite as durable as the sand- 

 stones. The ability to resist the action of heat determines 

 the value of a stone for fire-proof construction. But in any 

 fair comparative estimate of the value of the several kinds 

 of building stone — granites, marbles, limestones and sand- 

 stones — the considerations of appearance, beauty, ease and 

 economy of working, locality, as well as the conditions of 

 exposure, are important. And no rigid scale of credits or 

 gradations by sharp lines of demarcation are possible. 



The results of these comparative tests of the durability of 

 * the more common building stones in use in our cities, are 

 Indicative of valuable properties in the best stone from 

 quarries in the state and of superiority over those from 

 other quarry districts of the country. New York has within 

 Its limits almost inexhaustible deposits of granites, sand, 

 stones, limestones and marbles of such superior quality- 

 And for durability, some of its sandstones and blue-stones 

 are the best In the world. The 'Tife" of such stones, or 

 the length of time which they may last, as durable material 

 In buildings, cannot be known from the oldest structures, in 

 which they are still almost as fresh and as strong as ever. 



