Report of the United States National Museum ...U.S. Government Printing Office, 1889 |
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Seite 453 - mellowing with age " is now claimed as one of the good qualities of the stone. When, however, the pyrite occurs in such quantities as to produce by its oxidation unsightly blotches its presence is, of course, objectionable. The principal quarries of the stone at present writing are situated in the towns of Amherst, Berea, East Cleveland, Ilyria, and Independence in Lorain and Cuyahoga Counties. At Amherst the quarries are located in a series of ledges which were once the shore cliffs of Lake Erie....
Seite 350 - ... are more or less driven forward into the softer parts. In looking at similar surfaces which have been a long time exposed to the weather, it will be seen that the stone adjacent to the seam presents an interrupted fractured margin; the small fragments having dropped out in the process of weathering. Limestones of this character are much better adapted to rough dressing, when the blows are directed away from the surface instead of against it, and when the entire surface shall be left of the natural...
Seite 306 - as a rule," run perpendicular, or approximately so, to the planes of bedding, and descend vertically at not very unequal distances, so that the portions of the rock between them, when seen from a distance, appear like so many wall-like masses. An important feature of these joints, as mentioned by this authority, is the direction in which they intersect each other. In general they have two dominant trends, one coincident on the whole with the direction in which the strata are inclined from the horizon,...
Seite 351 - In applying, the surface to be coated is first heated by means of especially designed lamps and charcoal stoves, and the melted compound applied with a brush. On cooling it is absorbed to a depth dependent upon the degree of penetration of the heat. In the case of the obelisk, Mr.
Seite 357 - Liberty; also one some 2^ miles west of New London. Continuing in the same direction the bed is seen at the meadows of Goose Creek, where it has been quarried to some extent. Parallel ranges of soapstone appear near the Pigg River in Franklin County. About 30 miles southwest from Richmond, at Chula, in Amelia County, there are outcrops of soapstone said to be of fine quality, and which in former times were quite extensively operated by the Indians. They have been reopened within a few years and the...
Seite 374 - The most interesting building material in the entire state of Maryland is the " Potomac marble," " calico rock " or " Potomac breccia," which has been used occasionally for the greater portion of the century.
Seite 350 - The problem, as may be readily understood, consists in finding some fluidal substance into which the stone may be dipped or which may be applied with a brush to its outer surface in such a manner as to fill its pores and thus prevent all access of moisture. Whatever the substance, it must be of such a nature as in no way to discolor or disfigure the stone. Paint. — This is one of the substances most generally used, and which has been employed on the porous sandstone of the Capitol, White House,...
Seite 320 - When adjusted for work it maybe braced by the pointed legs shown. The boring apparatus is attached by a swivel to a perpendicular guide-bar. This guide-bar is secured to the boiler behind it, which forms the main support of the machine. Upon the guide-bar the boring apparatus may be raised or lowered at pleasure, for the purpose of boring a series of holes in a perpendicular lino if desired.
Seite 312 - When this work was finished, it was the wonder of the country round. People coming from a distance made it an object to see and admire this great structure. The wonder was that stone enough could be found in the vicinity of Boston fit for the hammer to construct such an entire building. But it seemed to be universally conceded, that enough more like it could not be found to build such another.
Seite 22 - ... the idea which any object is intended to illustrate should be explained upon its label in such a manner that any intelligent visitor, without previous special knowledge of the subject, may be able to learn (a) why the object is shown, and (b) what lesson it is intended to teach; (III) the objects should be so carefully classified that their relations to each other may be recognized by the visitor, so that, taken together, they suggest certain general conclusions...