[23 J 6 



at command, and he was requested to subject these to a process recom- 

 mended by Brard, a French chemist, and described in the '^Annales de 

 Chimie et Physique;" according to AA^hich, the crystallization of the sul- 

 phate of soda is substituted for the freezing of water; and thus, by artificial 

 means, the action of the elements on these materials — the alternate freezing 

 and thawing to which the external component of a building is in this cli- 

 mate annually subjected — is in a measure imitated. The result — which, 

 however, in consequence of the short time which could be allowed for the 

 process, must be considered an approximation only to the truth — is given in 

 a report from the gentleman in question. The specimens were reduced to 

 inch cubes; and it was found, after four weeks, that a cube of granite had 

 lost about one-third of a grain; a cube of the fine-grained marble about one- 

 fifth of a grain; a cube of the best quality of the "alum-stone," or coarser- 

 grained marble, half a grain to a grain and a half; and a cube of freestone 

 from the Patent Office, which, however, was judged not to be a fair average 

 specimen of the Aquia creek freestones, lost eighteen grairis and a half. 

 Freestone from Trinity church lost from two-thirds of a graiti to about a- 

 grain anda Jtalf. The brown Connecticut stone, freely used in New York, 

 lost from fourteen to nearly twenty five grains. Coarse-grained New York 

 marble, from Mount Pleasant, lost nearly a grain; Nova Scotia coarse- 

 grained sandstone about two grains; while Pennsylvania blue limestone 

 lost little over a quarter of a grain. 



As to the relative cost of the Maryland granite, Maryland marble, fine- 

 grained and coarse grained, Aquia creek freestone and Seneca creek free- 

 stone, it was found, from the report of the geologist and from actual ofl'ers 

 made to the committee by owners of quarries, and Avhich will be found re- 

 corded in the journal of the committee, to be, per cubic foot of dimension 

 stone delivered in Washington, as follows: 



1st. For coarse-grained marble with large crystals, commonly called 

 "alum- stone," from fifty to sixty cents, according to quality. 



2d. For fine-grained marble, the lowest oifer was seventy cents. 



3d. For granite, forty -six cents. 



4th. For Aquia creek freestone, /o?'^y cents. The material used in the 

 public buildings in Washington, in blocks of ordinary size, has cost from 

 forty io fifty cents. 



5th. For Seneca freestone, the lilac-gray variety, fi:om Bull Run quarry, 

 twenty cents. A contract has been made by a gentleman of Washington, 

 not connected with the institution, to have stone from the Seneca creek 

 quarries delivered to him in the city at thai price. 



East Chester marble was otfered at seventy five cents. 



The committee ought here to state, that the proposals by owners of 

 granite and marble quarries in Maryland to deliver material for our build- 

 ing were at a considerably lower rate than they otherwise would have been, 

 in consequence of the liberality evinced by the directors of the Baltimore 

 and Ohio railroad, and of the Baltimore and Susquehanna railroad, towards 

 the institution. The chairman of the committee had an interview with 

 Mr. McLane and Mr. Howard, the presidents of these railroads, and the 

 directors of both companies passed resolutions, that if we decided to use 

 Maryland marble or granite, they would transport it at the rate of tico and 

 a half cents per ton per mile, instead o^ four cents, the usual charge for 

 the transportation of similar materials. As it happened, the committee had 

 no occasion to avail themselves of this liberal proposal ; but it doubtless 



