REPORTS OF THE BUILDING COMMITTEE. 609 



So confident are the quarrymen of the certainty of splitting this granite in any 

 required direction, when even of no greater thickness than nine inches or a foot, that 

 they will, for the sake of having weight and substance in the block to retain it in its 

 position while under the hammer and chisel, first dress the two outside faces, and 

 trust to splitting the slab or block in two. 



Fully to appreciate the quality of this granite, the quarries themselves must be 

 visited, and the huge block in mass inspected as they are removed from their original 

 bed. There, one may see a perpendicular face of nineteen feet presented to view, 

 extending twenty, thirty, and even forty or fifty feet, without a seam or flaw, or the 

 slightest variation in hue. A mass of forty or fifty tons weight may often be seen 

 severed from the parent rock, by the simple but efficient means of small iron wedges. 



On some slabs, by close inspection with tbe magnifying glass, a few minute specks 

 of iron pyrites may be seen ; but none were observed visible to the naked eye. 



Mr. Green thinks nearly one-third of the freight may be saved by bringing the 

 rock to its proper dimensions at the quarry. 



This granite does not spaul freely ; but, in consequence of the facility with which 

 it splits, but little spauling is required. 



From the bottom of the Waterville branch quarry to the summit of the outburst 

 is forty feet, by barometrical measurement. 



The Fox rock quarry is thirty-six feet from top to bottom, where now excavated. 

 It might be worked some fifteen or twenty feet lower before being incommoded by 

 water. Mortar adheres with such force to this granite, that, when fairly set, it 

 requires as much force to separate the substance of the granite as to detach the mor- 

 tar from the face. 



On the whole, the inspection of these granite quarries has impressed me with the 

 belief that no locality can furnish a superior quality of granite, and that it cannot be 

 surpassed for strength and durability by any building material in the world. 



The stonecutters' bill in granite will, I fear, run up very high on account of its 

 great hardness; but, if the expense be not an objection, I do not think that there 

 will be any practical difficulty in rendering in granite ornamental woi-k so little elab- 

 orate as that of the Norman style. 



An objection to the use of granite for the Smithsonian building deserves serious 

 consideration. It is, that, in this material, the effect of light and shade is, in a great 

 measure, lost; while every projecting ornament in marble is marked by a dis- 

 tinct shadow. How far this may injure the general effect under the plan adopted, 

 the committee will judge. Eesults of considerable practical importance may be 

 obtained by an accurate chemical analysis, chiefly with reference to the proportion of 

 silica, alumina, magnesia, and iron, affecting the durability, discoloration, and ex- 

 pense of working. Time, however, did not permit this investigation. 



All of which is respectfully submitted. 



DAVID DALE OWEN. 



"Washington, March 11, 1847. 



List of Specimens referred to in the foregoing Report. 



No. 1 Kobinson and Fell's quarry. 



la Robinson and Fell's lower layer, close to Cold Spring creek. 



2 Griscom and Burrough's quarry. 



2a Griscom and Burrough's top layer, banded with light gray. 

 lab Griscom and Burrough's fine grained, in nests. 



3 Symington's quarry, large crystalled marble. 

 3a Symington's quarry, sample of large blocks. 



4 Fell and Robinson's quarry, blue variety. 



5 Mrs. Taylor's quarrj\ 



5a Mrs. Taylor's quarry, crumbling layer. 



66 Mrs. Taylor's quarry, (see specimen with dark color on long exposed sur- 

 face. ) 



5c Mrs. Taylor's quarry, banded with gray stripes. 



5d Chisilla Owen's quarry, fissured. 



6 Chisilla Owen's quarry. 



7 Worthington's (old) quarry. 



8 Baker and Conly's quarry. 



10 Worthington's (new) quarry. 

 lOw Worthington's white variety. 

 10W Worthington's blue variety. 



11 Cooper's quarry, with veins of mica. 



39 



