110 KEPORT OF ASSISTANT DIRECTOR OF NATIONAL MUSEUM. 



A portion of these are living water plants, and have been assigned to 

 the superintendent of the government carp-ponds, under whose charge 

 the Fish Commission has developed an extensive plantation of water- 

 lilies and other interesting aquatic species. 



MINERALOGY AND ECONOMIC GEOLOGY : GEORGE W. HAWES. 



In the department of mineralogy, under the direction of Dr. G. W. 

 Hawes, there has been great activity during the year. The mineralog- 

 ical and metallurgical materials, collected in all parts of the country for 

 the Centennial Exhibition, and presented by foreign governments at its 

 close, and which for five years past have occupied the two lower stories 

 of the armory building, have all been unpacked and assorted, and the 

 greater portion of them removed to the new building. Many of the most 

 bulky and interesting blocks of minerals and ores have been iilaced on 

 exhibition on a concrete pavement outside of and along the west main 

 hall of the new building. Dr. Hawes, in connection with an investiga- 

 tion upon the building-stones of the United States, which he is carrying 

 on in behalf of the Tenth Census, has gathered specimens of stone from 

 every quarry in the United States; and a force of fifteen men, in part 

 detailed from the Census Office, has been occupied all the year in pre- 

 paring them for study and exhibition. The blocks, which are, for the 

 most part, received by mail in a rough condition,' have been dressed and 

 polished in four-inch cubes. These cubes, when finished, show upon 

 different sides the appearance of the stone when polished, ax-ham- 

 mered, bush-hammered, rough-faced, drafted, and rough. 



Up to the 1st of January, 1881, there have been forwarded by special 

 agents of the census, or by other persons upon their solicitations, 3,030 

 specimens of building-stones, representing nearly every quarry of im- 

 portance in the United States. Of this number 1,277 have been dressed 

 in the manner just referred to. The Museum had already in its posses- 

 sion 535 dressed specimens, many of them in blocks a foot square, or 

 larger,, and beautifully polished, showing the products of many of the 

 principal American quarries, and those of several foreign countries. 



Numerous analyses of building- stones by the chemical and specific 

 gravity methods have been made by Messrs. F. p. Dewey and F. W. 

 Taylor. 



Since the 1st of June, Mr. Geo. P. Merrill has prepared 1,550 micro- 

 scopic slides of building-stones, to be used in connection with the inves- 

 tigation. 



In addition to the building-stones received, there have also been fifty- 

 seven accession lots, among the most important of which are a mag- 

 nificient collection of stalactites and stalagmites from the Luray Caverns, 

 the gift of the Shenandoah Valley Eailroad Company, and an extensive 

 series of minerals from the Yellowstone National Park, including the 

 top of a geyser with seventeen openings, obtained by Col. P. W. Norris,. 

 superintendent of the park. 



