5 20 THE POPULAR SCIENCE MONTHLY. 



knowledge of every man, and therefore such as may most fitly be set 

 forth in a publication outside of that field of special and technical 

 record which is devoted to professional observation and experience. 

 Nineteenth Century. 







BUILDING AND ORNAMENTAL STONES OF THE 



UNITED STATES. 



Br GEORGE P. MEEEILL. 



WHEN, early in his curatorship in the National Museum, Dr. George 

 W. Hawes, one of the leading American lithologists, assumed 

 charge of that branch of the tenth census relating to the quarrying 

 industry of the United States, it is doubtful if any but himself fully 

 realized the importance of the undertaking aside from its statistical 

 bearings. Dr. Hawes was, however, not a man to be satisfied with fig- 

 ures alone, or one who considered the scope of a census to be merely the 

 compilation of statistics, and in selecting his assistants he did so with 

 especial reference to their qualifications in other lines of work as well. 

 Thus we find upon his list the names of such geologists as Professors 

 Shaler and Wolff, of Harvard ; Hitchcock, of Dartmouth ; Winchell, of 

 Minneapolis ; and others of equal note and ability. These assistants, or 

 special agents as they were called, visited each quarry in person within 

 their respective districts, and, together with collecting the -necessary 

 information relative to the amount, kind, and value of stone quarried, 

 number of men employed, etc., made all possible observations in regard 

 to the geological age of the stone, its disposition in the quarry, weather- 

 ing qualities as displayed in those portions of the outcrop that had been 

 exposed for ages to the action of atmospheric agencies, and, lastly, 

 selected samples of the rock in the form of blocks of sufficient size to 

 dress into four-inch cubes and forwarded them bv mail to the National 

 Museum, at Washington, for further examination.* Here a corps of 

 assistants was employed who selected samples for chemical and micro- 

 scopic analysis, and left the block to be handsomely dressed into a 

 four-inch cube and placed permanently upon exhibition, having mean- 

 while made careful notes upon its working qualities. Small chips of 

 each rock were ground into films so thin as to be perfectly transparent, 

 and submitted to microscopic examination in order not only to deter- 

 mine what the rock was, but also to ascertain if it contained any min- 

 eral constituents liable to unfavorable change on exposure to the 

 weather. Whenever necessary, chemical analysis was resorted to to 

 further aid in the solution of the problems involved. 



* These blocks weighed from six to ten pounds each, but, being Government matter, 

 were allowed to pass through the mails, though greatly exceeding in weight the limit set 

 by law. 



