MINERALOGY. 257 



among the Miner a Arenacex or Sand- 

 Ores ; (Sed. cclxxvii.) at lead when the 

 martial ochre makes any confiderable 

 portion of the whole *. 



SECT. CCLXXVII. 



C. Stones and ores cemented together, Saxum 

 fragmentis conftans lapidum et miner arum con- 

 glutinatis. Miner a Arenace*. 

 1. Of larger fragments, Fragmentis lapi- 

 dum et miner arm* majoribus. 

 a. Mountain green, or Viride Montanum 

 Cupri, and pebbles cemented together, 

 from Siberia. 



* Sandftones are of great ufe in ceconomy, as materials for 

 buildings which rcfift 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 fandilones are the moft ufeful ; but the 

 folid and hard ones, fuch as c. and d. crack in the fire, and 

 take a polifh when ufed as grindilones. However, though the 

 Burfwik's ftone, (i. h.) is pretty loofe in its texture, it is never- 

 thelefs unfit for buildings winch are expofed to fire or open air, 

 becaufe it breaks to pieces and melts in the fire, and in the air 

 it attracts the moifture, decays in length of time, and cracks 

 in the cold, which proceeds from the included kernel? of clay 

 expanding themielves when they grow wet; the fandflones 

 ought therefore to be very nicely examined before they are 

 employed to the ufual purpofei?. 



There are many quarries of far.dftones in Sweden, but no 

 enquiry has yet been made if any c. : them, and which, can be 

 employed in the larger works, inftead of the Englifh, and i.i 

 the fmaller manufactories inftead of the Bohemian fandftones. 

 Such enquiries are of greater cenfequence, in proportion as 

 thofe manufactures encrtafe wherein they are wanted. It muft 

 be remarked, that the working mafons or ftone-c'utters enghc 

 to wear a piece of frieze or baize before their mouth and nofe, 

 in order to preferve themielves from a premature death, which 

 now-a-days unhappily is the cafe with them, in the parifh of 

 Or fa in Da'arne, and in other places ; but lir/icflone is not 

 found to have this bad effect. 



S b. Potters 



