REPORT ON NATIONAL MUSEUM. 165 



THE COLLECTION OF BUILDING STONES. 



About the time that Dr. Hawes entered upon his duties as a curator 

 at the National Museum he also assumed charge of that branch of the 

 Tenth Census relating to the quarrying industries of the United States. 

 His plan was to make acompletecensusof all thequarriesof stone worked 

 in the country, to ascertain the amount and value of their productions, 

 the number of men employed, and all the facts usually included in cen- 

 sus reports; in addition to which it was hoped to gain a large amount 

 of information of more strictly scientific interest. In order to carry out 

 his plans, special agents or collectors were employed, in all cases in 

 which it was possible, men of scientific attainments, whose education and 

 training had especially fitted them for the work, who were to visit the 

 quarries in person and gather all necessary facts of economic import- 

 ance relative to the industry, besides which they were instructed to col- 

 lect all additional facts possible of scientific importance but perhaps of 

 less practical value. Among the printed questions to be answered rela- 

 tive to each quarry were the following: "Kind of rock quarried?" 

 " Geological age of formation ?" " Structure of natural blocks as regards 

 stratification and jointing?" "How large a block can be obtained?" 

 " Principal uses for which it is employed ? " &c. ; or, if the stone was 

 used for ornamental purposes only, there were added such questions as, 

 *' What are the qualities that render this stone desirable for ornamental 

 purposes ? " and, "Is it suitable for ornaments exposed to the weather ? ". 



From each quarry two specimens, or more if the character of the rock 

 seemed to require it in order to represent it in all its varieties, of suffi- 

 cient size to be dressed into four-inch cubes, were forwarded by mail 

 to the Museum for further examination. Here a corps of aids and 

 assistants was employed to work up the material as it came in. Each 

 specimen on its arrival, after being catalogued, was placed in the hands 

 of stone-cutters who dressed them into four-inch cubes the different faces 

 of the cubes being finished as follows : Polished in front, drafted and 

 pointed on the left side ; drafted rock face upon the right side ; rock 

 face behind, and smooth sanded or chiseled upon the top and bottom. 

 This preparation was modified to suit individual cases ; for example, 

 sandstones which do not polish, had the front face simply rubbed 

 smooth. The si)ecimens thus prepared were placed in suitable exhibi- 

 tion cases and properly labelled, where they might be examined by all 

 who wished. 



The chips made in the process of dressing were carefully saved to be 

 utilized in chemical and microscopic analyses. Also specimens from 

 each quarry, so far as practicable, were to be submitted to proper tests, 

 to ascertain their powers of resistance to pressure. Special tests were 

 also to be made to learn the absorptive properties of the various kinds 

 of stone ; their specific gravity and weight per cubic foot ; their powers 

 of resistance to the effect of heat and frost, together with the effect of 



