Fluids in the Cavities of Minerals. 
Art. V.— Fluids in the Cavities of Minerals. — 
WE have long owed to Dr. BREwstTeEr, of Edinburgh, a 
eorrection of a hasty statement respecting the new fluids 
which he discovered in the cavities of quartz crystals, topaz, 
and other minerals. These fluids were incidentally mention- 
ed, in an account which we drew up in the summer of 1824, 
and pees in the Sth volume of this Journal, p. 282, en- 
itled “Facts tending to illustrate the formation of crystals 
in geodes.” The fluids discovered by Dr. Brewster, were 
mentioned, as objects only of microscopic observation. Mi- 
croscopes were used in examining the phenontena, but it is 
also true, as Dr. Brewster remarks, (Edinburgh Journal of 
Science, Vol. [I. p. 141,) “that some of the cavities are 
nearly the fifth of an inch long, and that the fluids have been 
taken out of the cavities, looked at with the naked eye, and 
touched, tasted and subjected to chemical experiments.” 
1e discovery of Dr. Brewster appeared to us very inte- 
resting, and we cited the earliest notice of it from the Edin- 
oy Journal. (See Vol. VIL p. 186, of this Journal.)— 
e hay i 
On the existence of two new Fluids in the Cavities of Min- 
erals, which are immiscible, and possess remarkable physi- 
Properties. By Davip Brewster, LL.D, F. R.S. 
Lond. and Sec. R. S. Edin. 
_THE unpublished memoir, of which we now propose to 
give an abstract, is divided into eight sections, namely, 
Sect. 1. On the existence of a new fluid in the cavities of 
Sect. 2. On the co-existence of two immiscible fluids, of 
= ° es of » als, 
werent physical properties, in the cavities and 
accompanied with a vacuity. 
