19 
TAB. CCXL. 
Rotten Stone. 
Ix Derbyshire, about two miles west of Bakewell, is found 
some variety of this remarkable substance in land belonging 
to the Duke of Rutland. It is said to be found also in 
Shropshire and Somersetshire, and I have a seemingly 
chance specimen from Sussex, by favour of Mr. Borrer, 
Near Bakewell it is found in broken nodules or fragments 
in the upper soil to about eighteen inches deep or more. 
It should appear that some parts of the rocks in the neigh- 
bourhood are in a state suited to a certain decomposition, 
by exposure on the common surface, mouldering in a pe- 
culiar manner into a more or Jess coherent, fine, dusty, 
soft, but somewhat granular appearance. The rock varies 
from a light brown to a deeper and grey or blackish hue. 
In decomposition it becomes lighter, and passes from dark 
to light yellowish brown, in which state it 1s commonly 
called Rotten Stone. It is sold to be used in manufactories 
for polishing metals,.&c.; but.is more particularly ne- 
cessary to the lapidaries*, who polish the harder stones 
with it, by the help of water, and the substance of their 
machine being of a harder or softer metal according to the 
nature of the stone, as Lead, Copper, &c. Nature in this, 
as is always invariably the case, has furnished us with a 
substance so nicely suited to this particular purpose, that it 
* Lapidaries sometimes cut and polish the more curious glass, imitative 
of precious stones (commonly called paste) ; but this is considered as rather 
degrading to the profession, and it might seem degrading to the glass po- 
lishers to teach them to polish glass. Rotten Stone is certainly so hard in its 
nature, as rather to grind the glass, as they would call it. Putty is used for 
polishing glass. It is an Oxide of Tin. 
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