678 GEOLOGY OF OHIO. 
The two districts for yellow and Rockingham wares are Colum- 
biana and Hamilton counties. The former uses clays from the im- 
mediate neighborhood and has ten or more establishments. The clays 
are from the Lower Kittanning horizon and are mined by drifts. In 
East Liverpool there are nine large yellow-ware works, as follows: 
Noner & Gastome socos8e vs .cececnscteens ccencdse cccascspestemeese eee mtrnene 3 kilns. 
Si EW Bae eote sss loi A Soe hG RS Act oa wate ere meee aren eyes Danae: 
Cartwright) Brosispess eco ce ieee tee ARE tae Sawn atae nea nose A 
Croxall) & Cartwright .io<5: cc.css...-ccocece se ocseene occa ceamteon eine aces 4 *“ 
Flentke & Harrisonivs:22. 2 osc bec se secdesene oestetes eee ee ee ee eeaeee eae 
Bredeérick, Shenkle, Allen &)Cosi.0.c0s clocepssmocsensencedeccmedonts Suche 
MeDeavitt& Moore ee.c.8 i aks oicetnc eeeonc aoe oab ees eee es ee eee neta Paes 
MicNicolBurtonide Co) cecwaiss occ acos oe seen cetec aren sesaemesecceeeeeen ee: By 
C. C. Thompson & Co. (also make white-ware)............ .: Sean OWS 
And at Wellsville are found the works of John P.tterson & Co., four kilns. 
The Cincinnati district has ten potteries, including all kinds of 
ware, white, yellow, Rockingham and earthen. The clays used here 
are all imported and come in part from Lawrence county, being the 
Kittanning clays and the Ferriferous limestone clays of that district. 
The other points where yellow-ware is made are few in number. Por- 
tage county is the largest center of production after the points named. 
The process is much the same in all the districts. It differs from stone- 
ware processes in the superior skill and care used in all the steps, and 
is indistinguishable from the processes for white-ware or ironstone 
china except in the kinds of material and glazes used. 
The clays as they are brought from the mines are allowed to slack 
in the air. No definite time is used in this process, as the clay is used 
as fast as needed, but a large enough pile is usually kept ahead to secure 
at least partial weathering. The clay is put through the process called 
washing, which is a common means of purifying all clays. The first 
step is mixing the clay into a thin slip, or as the potters call it, “ dis- 
solving” it, though it is only in a state of mechanical suspension and 
not in true solution. ‘This is accomplished in what is termed a “blun- 
ger.” It is a cylindrical vat varying from 4 to 6 ft. in diameter, in the 
center of which works a rod bearing arms suitably arranged to stir the 
clay up till it is all in a state of suspension. The slip is run out of the 
machine from a faucet, while still revolving, so that the clay will keep 
in suspension, into a bolting apparatus. This isa box slightly inclined 
with a fine bolting-cloth bottom. The slip runs through, leaving all 
