NOTES ON THE TABLE OF TESTS 369 



It is notable that the oolitic stones showed a gain of 0.16 to 

 0.19 per cent, due to the replacement of the calcic carbonate, 

 in part, on the greater area of interstitial surfaces in these 

 more porous stones, by the calcic sulphate formed by the ac- 

 tion of the sulphurous acid. 



The sandstones exhibit a wide range of loss, amounting 

 to one hundred times as much in the Oswego Falls stone as 

 in the Maiden blue-stone. The losses in the Potsdam and the 

 Lake Superior stones also are small. The Berea, Ohio, the 

 Bristow, Virginia and the Warsaw stones are large losers. 



The action of the dilute sulphuric acid upon the granites, 

 sandstones and slate was as follows : 



Per cent of loss 

 in weight. 



Potsdam sandstone 0.02 



Ausable granite 0.06 



Red roofing slate, Middle Granville 0.07 



Sandstone, Albion 0.08 



Sandstone, Hulberton 0.08 



Granite, Hallowell, Maine 0.08 



Sandstone, Worcester, East Longmeadow o.ii 



Sandstone, Bristow, Virginia o.ii 



Sandstone, Kibbe, East Longmeadow o.i i 



Granite, Grindstone Island 0.13 



Sandstone, Maynard, East Longmeadow ... 0.17 



Blue-stone, Maiden 0.20 



Sandstone, Oxford 0.20 



Sandstone, Nova Scotia 0.20 



Sandstone, Portland, Connecticut 0.22 



Sandstone, Lake Superior, Michigan 0.36 



Sandstone, Portage 0.42 



Sandstone, Olean 0.44 



Sandstone, Berea, Ohio o 45 



Sandstone, Warsaw 0.49 



Sandstone, Portland, Connecticut 0.55 



Sandstone, Duanesburgh 0.63 



Sandstone, Oswego Falls 0.74 



Sandstone, Belleville, New Jersey i.oi 



The effects of repeated and rapid changes of temperature 

 in alternate freezing and thawing, can be grouped in the 

 class of sandstones, as follows : 

 47 



