358 Messrs. Johnson and Blake on Kaolinite and Pholerite. 
employed in the imperial porcelain manufacture at Vienna, one 
of which is “fat” and the other “short.” The composition of 
the two is almost identical (see Chem, Centralblatt, 1865, p. 268), 
and the different degree of plasticity is thus evidently connected 
with their state of division. 
It is possible also that the plasticity of a clay is related to the 
form of the plates of kaolinite, perhaps to their thickness, but 
this is a subject that requires further investigation. Our obser- 
vations indicate that the impurer sedimentary clays are the most 
lastic. Some of these are perhaps not so fine as “shorter” 
aolins. The plasticity may be, therefore, in part due to the 
impurities. 
In the subjoined table are given the analyses of various crys- 
tallized kaolinites which have been previously referred to. 
Analyses of crystallized Kaolinite. 
So eo eS 
( ite), Freiberg, Saxony, R. Miiller, 4774 3948 1407  -..- 
«  (Pholerite), Summit Hill, Pa., S. W. Johnson, 45-93 3981 14-02 .... 
% 65 1369 O17 
Wanhnita (WN. 
, Tamaqua, Pa., F. A. Genth, 46°98 39: 
- (Kaolin), Richmond, Va., B. S. Burton, 48°56* 35°61 1288 2:95 
¢ (Steinmark), Schneckenstein, Saxony, W. S. 
Clark, 4676 35°59 1842 94 
” (Kaolin), Zeisigwald, Sax. A. Knop, 4991 85:23 1486+ ..-- 
( “  ), Altenberg, “  R. Richter, 45°63 39°89 13°70 0°60 
(Pholerite), Lodéve, France, Pisani, 4700 38940 1440 ...- 
“ Schlan, Bohemia, Stolba, 86-718 15:29. ws 
- , 47-93 : 
Calculation after Gmelin (Si=15, AlI=13-7) requires, 47:19 39:12 13°69 
‘ “« Rammelsberg (Si==14'8, Al==13-68) 
requires, 4705 39°21 13°74 
hy “ Fresenius (Dumas) (Si=14,£l=13-75) 
requires, 4633 39°76 13°90 ,.-- 
* Including some quartz. + By difference. 
