E XX 3 
-hot belong to them, other colledions will be 
augmented ; and thus every thing will be 
brought into a due order. If fome colledtors 
fliould not immediately be able to comprehend 
this Syflem or Claffification, it cannot much 
detriment the fcience^ and it is likewife of very 
little confequence in proportion to the advan- 
tage that Will accrue to the ftudy by this me- 
thod, the more it fliall be cultivated and 
improved. 
Ptolomy cannot be fuppofed to have known 
the value of every book be fent to his great li- 
brary in Alexandria, and he had doubtlefs no 
time to clafs them himfelf according to the con- 
tents of the different books acquired ^ however, 
his love for colleding muft have continued during 
his life : Moreover, the advantages obtainable 
from it would have been afterwards difcovered, 
had it not been difperfed ; or, as fometimes 
happens, had not the colleftion been fuppofed 
to gain fome additional value by being made 
difficult of accefs to the learned. 
As foon as we are arrived to fuch a pitch, as 
by the examination of a mineral body to dif- 
cover or knov/ all its conftituent parts, and can 
affert with certainty that it can be no further 
decompounded by any method hitherto known ^ 
then fuch a body ought, according to the in- 
tention of this Effay, to receive its fpecific 
name, and not before ; for otherwife it will 
be vague and trivial. However, I have not 
affumed a confidence to do this even with fuch 
mineral bodies that I in fome refped: can aver 
1 pretty ’ 
