REPORTS OF THE BUILDING COMMITTEE. 



601 



removed and hung upon a frame over half-pint bowls, containing also a quantity of 

 the cold saturated solution. 



In the course of 24 hours a considerable efflorescence was found upon the surface 

 of each specimen, consisting of the crystals of the salt mixed with comminuted 

 portions of the stone. These were washed off daily, by simultaneously immersing 

 the stones in the solution in the bowls, and suffering them to remain there for a few 

 minutes. This proceeding was repeated daily for one week, when it became necessary 

 to deviate from Brard's directions, and to keep them in a moderate temperature, 

 instead of a cold cellar, as he advises. It was obvious that the investigation would 

 be exceedingly protracted unless the crystallization of the salt were promoted by 

 moderate warmth, as by this time the detritus from some specimens was hardly vis- 

 ible. 



After the change, the process went on with greater rapidity ; and at the end of 

 four weeks the dipping was stopped, and the sediment or deposit in each bowl was 

 earefully weighed, and furnished the results as given in the table. In some cases the 

 comminution of the stone was exceedingly fine ; and in the washing and decanting 

 process, ample time was allowed for the deposit to settle after each washing, and the 

 utmost care used in the subsequent operations of decanting, drying, and weighing. 

 The time of one week for the operation of dipping the stones in the solution was not 

 deemed sufficient, as the deposit from the marbles and some other varieties was hardly 

 apparent; and it was, therefore, continued, as above stated, four weeks, and thus the 

 slight errors of manipulation, if any occurred, are proportionally diminished. 



Disintegrating effects of frost upon stones used for Building Materials. 



Not tested; the' specimen being too small. 

 Symington's close-grained marble (similar to Worth- 



ington's) 



Connecticut sandstone, coarsest grained quality.* 



Dark red Seneca sandstone (similar to Peter's) 



Symington's large crystal marble 



Symington's blue limestone 



Coarse, large crystal marble, Mt. Pleasant, New York. 



Port Deposit granite 



Too small to examine. 



Trinity sandstone, fine grained and light colored * 



Connecticut sandstone, finer grained quality 



Nova Scotia sandstone, coarse grained 



Light Seneca sandstone, dove-colored 



Pennsylvania marble, close-grained 



Pennsylvania blue limestone 



Trinity Church light colored, close grained sandstone, 



New Jersey 



Patent Office light sandstone 



Soft brick 



Hard brick 



Granite from Potomac Great Falls* 



Dark coarse sandstone, of Seneca aqueduct, Peter's 



quarry * 



Sandstone, four miles above No. 2 D, Peter's, next 



west of Beaver dam quarry* 



Dark sandstone, from quarry near Wood's residence*-. 



Not tested, specimen being too small. 



Lower stratum, Beaver dam quarry* 



Specific 

 gravity. 



2.834 



2.G72 

 2.857 

 2.613 

 2.860 

 2.609 



2.583 

 2.518 

 2.486 

 2.727 

 2.699 



2.482 

 2.230 

 2.211 

 2.294 



Loss by- 

 frost, 

 n grains. 



0.19 

 14.36 

 0.70 

 0.50 

 0.34 

 0.91 

 5.05 



1.58 

 24.93 

 2.16 

 1.78 

 0.35 

 0.28 



0.62 



18.60 



16.46 



1.07 



0.35 



5.60 



1.58 

 3.94 



1.72 



* Specific gravity not ascertained. 

 Kespectfully submitted, by 

 "Washington, D. C, March 5, 1847. 



Laid on the table. 



CHAKLES G. PAGE. 



