es 
Or 
TAB. CCXIV. 
Dr. Bucuanan, whose researches in the East Indies are 
well known, brought me some of the Breccia Rock, from 
Callender in Scotland, in which I found pebbles of Feld- 
spath. As Feldspar of this description has not, to my 
knowledge, been before noticed, I am pleased to have an 
opportunity of showing it here, where I have added some 
other amorphous Feldspar, known by the name of Petuntse 
in Scotland, found in various parts of the Pentland Hills, 
south-west of Edinburgh. This is of some esteem in ma- 
nufactories of porcelain, being a fusible composition of Silex 
and Alumine, but varying in the proportion or quality. It 
often disappoints the workmen that gather it, as well as 
the manufacturers, and Quartz nearly pure has been sent 
to them as Petuntse, especially for the white or gray sort, 
which has least Iron, and would consequently be of most 
value for their purposes. 
