Messrs. Johnson and Blake on Kaolinite and Pholerite. 361 
In 1859 Prof. A. Knop Ser Soe an ee of a substance 
found at Niederrabenstein near Che , the purest forms of 
jemin’s mineral in com osition, or lie between - and olinite. 
In the subjoined table is given the composition of sheen: mine- 
rals and the percentages required by Guillemin’s of saa which 
is the one that has been deduced from Malaguti’s analyses of 
kaolin, viz., AlSi2 
bats we Other 
Sl Al H substances. 
Calculated, ron ctw dhe sana 39°30 4498 15-71 
Guille 0°75 43°89 15°36 
Bholerte, Fine, Guillemia, - 
4 Schemnitz | - 42°45 42°81 12-92 
39°34 45° 14-76 
< Naxos, J. L. enti _ - 4441 41:20 13°14 131 
Steinmark, Georastole, Du Ds 43:0 
wir Hammel, 43°46 41°48 13-49 157 
Toesite, Scotland, “Thom mpso 4430 4040 1350 1°25 
Richardson, = 4880. 4010—=«1481. 218 
The correspondence between the calculation and the analyti- 
cal results is not strikingly close. It is evident that most of the 
substances analyzed were not homogeneous, and future investi- 
gations must decide the yet open question, whethes these pho- 
lerites are not really impure kaolinite 
t is to be desired that mineralogists h having spec of these 
pholerites in their possession, should take measures to decide 
this point by a a of their physical properties, and by insti- 
tuting new ana atpsert on material p beeper purified or shown by 
the microscope to be homogeneou 
New Haven, Conn., March, 1867. 
* This calculation by Guillemin = bg rage ides by several writers as a 
third an analysis of pholerite from Rive-de-Gier. aaiye emin mentions the occurrence 
of pholerite at. Rive e-de-Gier, CbGE sisaibe 90: aint sis of the substance from that 
ocality. 
