ART OF BUILDING. 235 



foundation walls. Sandstone is used for building in 

 almost every part of the country. 



Limestone is of several kinds granular limestone 

 (Marble) and compact limestone (common limestone) are 

 the two principal varieties. All limestone is essentially 

 composed of carbonic acid, (dead orjixcd air) and quick 

 lime ; it is of various colors white, gray and veined. 

 This stone may be distinguished from all other building 

 stone, by putting a small piece into diluted sulphuric 

 acid, when it will effervesce or bubble like soda water, 

 which is caused by the acid combining with the lime, 

 and thereby setting the carbonic acid gas free. It is 

 about 2^ times heavier than water. 



Among all the kinds of limestone used in building, 

 marble holds the first place, both as respects durability 

 and beauty. Marbles are principally used for interior 

 decorations. The principal kinds are the following. 



1. White marble, which is used for statuary and 

 interior decorations ; the coarser kinds are often used for 

 exterior walls ; the City Hall in New York, and the State 

 Prison at Sing-Sing, in New York, are examples of this 

 species. This kind of marble is found in Vermont, 

 ( Middlelury ) Rhode Island, (Smithfield) and Massa- 

 chusetts, as well as many other places. 



2. Colored marble is of many shades, and is used prin- 

 cipally for interior decorations. It is found in abun- 

 dance in most parts of the country. 



3. Breccia marble is that kind of marble which is ap- 

 parently made up of different sized fragments imbedded 

 in different colored cements, the fragments are of all 

 sizes and shapes ; and when polished present a very 

 beautiful appearance. The most beautiful variety in this 

 country is found on the Potomac river, fifty or sixty miles 

 above Washington city. It is used for interior decora- 

 tions. The shafts of the columns in the Representatives' 

 Hall, in the Capitol, are formed of this marble ; they are 

 nineteen feet nine inches in height, and two feet in 

 diameter at the base. There are many other varieties of 

 marble, but they are seldom used by the mason. 



Granite. This is one of the best materials for the 

 construction of buildings, and is composed of three 

 substances, feldspar, quartz, and mica ; it is gra- 



