to be called Vitrcfcentes cum alcali , if their name 

 was to have any connection with their effects. 



Having now fo far overcome the former ig- 

 norance, which was the foundation of the know- 

 ledge for diftinguifhing the mineral bodies into 

 tranfparent or opaque, hard or foft, we prefer 

 the decifion of the fire, though we ftill labour 

 under the misfortune of not being able to mea- 

 iure the degrees of fire with fufficient accu- 

 racy ; for which reafon we always mud: fuppofe 

 a plus ultra in the experiments by fire. 



Sand in reality is nothing elfe than very fmall 

 fflones ; therefore, if a feparate clafs were to be 

 made of Sands, another clafs ought to be made, 

 which fhould comprehend Gravel , a third, 

 Loofe Stones ; and a fourth, Mountains : This 

 would be a mult ipli cat io entium prteter nceejjita- 

 iem , a fault, which under thefe circumftances 

 may ealily be committed, though not fo fooa 

 perceived. 



The Saxa muft for the fame reafon be exclud- 

 ed from any fyftem : Other wife it would be the 

 fame as if a botanift made a difference between 

 the mifletoes, or fuch like vegetables, according 

 to the different genera or fpecies of trees, plants, 

 walls, or rails on which they grew. 



Pet refactions, or Miner alia larvata, con lift 

 of fuch principles as ought to be defcribed in 

 their proper places, without regard to their 

 figure y for which reafon they cannot be enu- 

 merated a fecond time. The principal reafon 

 for collecting them, is to acquire a knowledge 

 Af fuch bodies of the animal and vegetable king- 

 doms, 



