20 HISTORY OF OHIO. 



and alumine ; and they sometimes, contain other ingredients, 

 which give them various colors. Their hardness is never great. 

 They are easily cut with a knife, and may be polished by the 

 finger nail. When thrown into water they crumble more 

 or less readily, and become minutely divided. Many of 

 our clays, when moistened, yield a peculiar odour, called ar- 

 gilaceous. Some varieties, by a due degree of moisture, and 

 by proper management, are converted into a paste, more or 

 less ductile, and constitute the basis, of several kinds of pot- 

 tery. Other varieties, when immersed in water, are resolved 

 into a fine, loose powder, nearly, or quite, destitute of ductili- 

 ty, and are employed as pigments. Such are found in Law- 

 rence county, where they vvcre formerly used instead of Span- 

 ish whiting. 



A few remarks on the uses of clays which are ductile, may 

 not here be out of place. These clays when duly moistened, 

 if they possess unctuosity, ductility and tenacity, are capable 

 of assuming various forms, without breaking. They possess 

 a strong affinity for water, hence their avidity for moisture, 

 and hence, they strongly adhere to the tongue or the lip. 



To the existence of clay beneath the surface, we are chief- 

 ly indebted, for all our springs, which rise and flow on the sur- 

 face, because these clays resist the further progress down- 

 wards, of the waters which falling on the surface, settle 

 downwards, until stopped by the clay beneath. They are then 

 compelled to rise in valleys, or run out of the sides of hills, 

 and descend into the valleys below them. They then form 

 rivulets and heads of rivers. 



Of all the earthy matters, clays contribute most to the uses 

 of man. They constitute the basis of bricks, with which, our 

 houses are built ; — they constitute too, the basis, of almost ev- 

 ery variety of pottery, from the homely, common earthen 

 ware, up to the beautiful, translucid procelain. On so exten- 

 sive a subject, a few facts only, will be brought forward, as 

 more, would not be tolerated, by the general reader. Clays 

 are essentially composed of silex and alumine, and this mixture, 

 in any given proportions to each other, is infusible, in any fur- 



