106 



GEOLOGY OF OHIO. 



1. Albany slip clay, average sample from three or four lots of the 

 clay. Orton. 



2. Albany slip clay. Langenbeck. 



3. Rowley slip clay. Orton. 



4. Brimfield slip clay, Summit county. Orton. 



5. Kaolite slip clay. 



6. Springfield slip clay, from Sharonville, Hamilton county. Lan- 

 genbeck. 



7. Bronhar clay, Zanesville. Langenbeck. 



Nos. 6 and 7 are not in use as slip clays, as far as is known, but were 

 tested with a view to determine their fitness. 



The Springfield slip clay was found to be an easily fusible clay, 

 which gives a greenish yellow glass, very similar to that produced by the 

 Rowley slip. 



The No. 7 Bronhar clay is used in making a fusible body for tilings 

 and is not used as a glaze at all. It requires too much heat to melt it. 



An examination of these clays for their oxygen ratio reveals the 

 following tabulated facts : 



TABLE Ha. 



No. 



Oxygen 

 in acid. 



Oxygen 

 in base. 



Ratio. 



Oxygen 

 in alumina. 



Oxygen 



in fluxes. 



Ratio. 



1 

 2 

 3 

 4 

 5 

 6 



30.72 

 32.37 

 23.44 

 33.94 

 32.21 

 22.53 



12.28 

 11.28 

 11.93 

 10.58 

 11.09 

 13.03 



2.50 : 1 

 2.80 : 1 

 1.96 : 1 

 3.20 : 1 

 2.90 : 1 

 1.73 : 1 



7.11 

 5.80 

 5.20 

 6.32 

 4.85 

 5.16 



5.17 

 5.77 

 6.73 

 4.26 

 6.24 

 7.87 



1 : .72" 

 1 : 1. 

 1 : 1.29- 

 1 : .67 

 1 : 1.28- 

 1 : 1.52: 



J 



udging froi 



n these fig 



ures, these 



clays are fi 



isible in th 



e following 



order : 



6:3: 5:1 and 2 : 4, and from the reports gathered among the potters,, 

 these figures are borne out in practice. 



The general character of the natural glazing clays thus is seen to be 

 as follows ; excessively fine grained sandy clays of about the following 

 average composition, 



Clay base 31.00 



Sand 39.00 



Fluxes 21.00 



Volatile (water and carbonic acid) 9.00 



100.00 



