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United Slates Department of Ayrirulture, 



BUREAU OF CHEMISTRY Circular No. 17. 

 HARVEY W. WILEY. Chief of Bureau. 



THE USEFUL PROPERTIES OF CLAYS. 



INTRODUCTION. 



From the earliest dawn of history man has exercised himself in 

 fashioning into products of beauty and utility the plastic materials 

 which he found prepared for his hand on or under the surface of the 

 earth. The stone age was followed by the bronze, and this in time by 

 that of iron, and this in turn by the age of steam and electricity; but 

 throughout all these changes the plastic arts have flourished in propor- 

 tion to the height of civilization that the peoples have reached. 

 Science and art, poetry and history combine to lend fascination to a 

 study of clays and clay working. Records of the manners and customs 

 of old and almost forgotten civilizations, such as the Mycenaean, or the 

 Mexican, are carefully gleaned by the archreologist from the more or 

 less crude linear markings and figures depicted on fragments of pottery 

 and statuary which have come down to us. From the few rude 

 earthenware chips which remain to tell us of our prehistoric- ancestors 

 to the finished and delicate porcelains of Dresden and Sevres, the 

 industry of man records its own development. 



Although in the direction of pure utility, as in the manufacture of 

 bricks, tiles, and common earthenware, much has been accomplished, 

 the fact is before us that, in the production of works of art and beauty 

 fashioned from clay, America is not to-day the equal of Europe. The 

 reasons for this are various and need not be discussed here. It is suffi- 

 cient to point out that they are not of such a nature as to prevent 

 America from ultimately achieving the highest position of all in this 

 domain. The fact that many tons of clay of various sorts are annually 

 brought across the ocean to us for use in our potteries, might seem to 

 indicate that our native clays were of themselves unfit for use. If 

 indeed this were true, it would be an insuperable obstacle to final suc- 

 cess, but the fact is that, although it may at present be more profitable 

 to import a clay than to develop a native source, America undoubtedly 

 possesses unusually rich clay and kaolin deposits, some of which are 

 fitted for the production of the most delicate and beautiful objects. It 

 is interesting to note that the pottery which has been a pioneer in 

 works of art made entirely of native clays was founded and fostered by 

 an American woman. It is by just such efforts that wider and further 

 growth will come. In these days of ardent emulation and competition 

 among the nations, it is fair to anticipate the time when an American 



