278 REPORT ON NATIONAL MUSEUM, 1886. 



texture, together with the locality from whence it was obtained and the 

 name of the donor or collector. 



The data for the accompanying hand-book has been likewise in part 

 supplied by the Tenth Census, in Yol. x, Report on Building Stones and 

 Statistics of Quarrying Industries. So far as possible statements taken 

 from this work have been verified by reference to the original schedules 

 now on file in this Department. The time that has elapsed since the 

 publication of the census report has, however, enabled me to gather 

 much new material, and to supply many facts there altogether omitted. 

 As the work is intended for popular use, it has seemed advisable to go 

 into considerable detail regarding the nature and composition of each 

 class of rocks, stating, so far as possible, the qualities that render them of 

 value for architectural purposes. Indeed it may be said that in putting 

 the matter in its present shape the curator has been guided largely by the 

 character of the requests for information which are being so constantly 

 received. These requests are from persons in all stations of life, but 

 most largely, as a matter of course, from those who are actively em- 

 ployed either in quarrying, building, or dealing in building materials. 

 With such it has rarely been found sufficient to give merely the name 

 of a stone submitted or inquired about, but such details as mineral com- 

 position, suitableness for any particular purpose, qualities good and 

 bad, how it differs from other stone with which it may be brought into 

 competition, etc., are almost invariably insisted upon. 



Inasmuch as the market value of a stone is so largely dependent 

 upon the cost of quarrying and dressing, it has been deemed advisable 

 to devote a few pages to an explanation or description of the various 

 machines, implements, and methods employed in this work. It is to be 

 understood that none of these machines are actually on exhibition 

 otherwise than by photograph or engraving. Only such are described 

 as have been found by the writer in actual use in the quarries, or which 

 seem sufficiently promising to merit attention. 



It is doubtless scarcely necessary to state that the results given in 

 Table 8 were not obtained from tests applied on these individual speci- 

 mens, nor at the Museum. They are compilations from a variety of 

 undoubtedly reliable sources, and a part of which have never before 

 been published. 



In speaking of any particular stone or group of stones it will be ob- 

 served I have not limited myself to a mere description of the sample aa 

 it appears in the Museum collections, but have gone more into detail re- 

 garding the quarries from whence it was obtained, its mode of occurrence, 

 use, and the natural facilities for quarrying and transportation. This 

 for the reason that, while many an outcrop is capable of furnishing sam- 

 ples of excellent quality for purposes of exhibition the stone may be 

 practically worthless owing to difficulties in the way of quarrying, lacfc 

 of transportation facilities, or distance from market. 



National, Museum, July, 1887. 



