257 
MINERALOGY. 
afnong the Miners Arenace^ or Sand- 
Ores ; (Se(5t. cclxxvii.) at leafl: when the 
martial ochre makes any confiderablc 
portion of the whole 
SECT. CCLXXVII. 
C. Stones and ores cemented together, Samm 
fragmentis -conjlans lapdum et miner arum con- 
glutinatis. Miners Arenace^e, 
1 . Of larger fragments,, Fragmentis lap- 
dum et miner arum majorihus, 
a. Mountain green, or Viride Montanum 
Cupri^ and pebbles cemented together, 
from Siberia. 
® Sandftones are of great ufe in ceqonomy, as materials for 
buildings which refill fire, air, and water, are made of them. 
Some of them are foft while in the quarry, but harden in the 
open air. The loofe fandllones are the moft ufeful ; but the 
folid and hard ones, fuch as r. and d, crack in the fire, and 
take a polilh when ufed as grindftones. However, though th« 
Burfwik^s Hone, (i. hi) is pretty loofe in its texture, it is never- 
thelefs unfit for buildings which are expofed to fire or open air, 
becaufe it breaks to pieces and melts in the fire, and in the air 
it attrads the moillure, decays in length of time, and cracks 
in the cold, which proceeds from the included kernels of clay 
expanding themfelves when they grow wet ; the fandllonea 
ought therefore to be very nicely examined before they arc 
employed to the ufual purpofes. 
There are many quarries of fandllones in Sweden, but no 
enquiry has yet been made if any of them, and which, can be 
employed in the larger works, inllead of the Englilh, and ia 
the fmaller manufadories in Head of the Bohemian fandllones. 
Such enquiries are of greater confequence, in proportion as 
thofe manufaftures encreafe wherein they are wanted. It mud 
be remarked, that the working- mafons or Hone-cutters onghs 
to wear a piece of frieze or baize before their mouth and nofe, 
in order to preferve themfelves from a premature death, which 
now-a*days unhappily is the dafe with them in the parilh of 
Orfa in Dalarne, and in other places j but limellone is not 
found to have this bad effecl. 
S J>, Potters 
