ter Tartar eous^ has put men upon ufing Medicines to de- 
ftroy tartareous Concretions, as well as avoid many things 
that feem to have T^r/-^r in them; and yet at the fame 
time perhaps it may be as inoffenfive as fome of thole 
Medicines that are fubftituted ; at leaft, as Spirit Salt 
or commonSalt commended by Helmont. In li e man- 
ner the notion of Petrification which feems,from whence 
the Stone deriv^es its Name, may be no lefs erroneous, 
there being no agreement or Analogy in their Natures 
whether we confider them Synthetically or Analytically. 
If we confider Stones in compofito, there is a particular 
Weight or GravityhQlongm^ to their Bulk^ in whxh they 
^ecifically agree. Several forts I have weigh d according 
to th^Hydroftatica^l Larvs^l find them agree in being twice 
as heavy as their Bulk of water^, and about a fourth 
part more. This I found true in Wood^ Bone, and shells, 
when petrified^and even water it felf,and fome othcxBodies 
tho never fo light in their former ftate, as foon as they 
have obtained the form ofjionetXitj all become of the 
mentioned weight or very near it. But this which is cal- 
led the iS^t?;?^ of the Bladder is m.vic\\\\g\itQ-v, and feveral 
of them agree in being only as heavy as their Bulk 
of water and ^i^th part more. This yields to none but 
ihQmo&.potent Acids and particularly to Nitrous ones a- 
, lone 5 the other is difl!blved by almoft any llight Corro- 
^ve. The one in our Analyfis affords various conftituent 
parts, and the other upon Dijiillation only a drop or two 
of infipid water, the reft remaining fixt. But we need 
not infift upon the difference which is fo obvious. 
Since 'tis much eafier to quarrel at other's Hypothefes 
than to invent better, in order to the giving lome ac- 
count of the Caufeoi this Nonnatural Concrete, I would 
lay down fome Confiderations. 
This Concrete may herhaps owe its Origine to a very foft 
and thin fluid^moxo, remotely to the chyle ftraiiied through 
the G^^J",and yet nearer the matter to the Blood it felf.but 
N 2 ncareft 
