335 
formerly supposed to be Zeolite , See. 
portion, exposed to a stronger heat for more than an hour, 
lost per cent. This operation was performed in a crucible 
of platina ; the cover of which gave some indications as if a 
slight portion of the finer parts had been volatilized. 
Some of the compact species, after exposure to a red heat 
for one hour, experienced a diminution in weight of 30 per 
cent. 
(10.) The sulphuric, muriatic and nitric acids, aided by a 
long digesting heat, effect nearly a complete solution of this 
substance. The quantity of the undissolved residuum is dimi- 
nished in proportion to the purity of the mineral employed. 
(11.) The nitrate of silver, as well as the muriate of barytes, 
produce no change in the solution of this substance in nitric 
acid. 
(12.) The solutions of this substance in muriatic and nitric 
acids, cannot be brought to crystallize. 
B. 
( 1 . ) I selected some of the crystals of this substance, as free 
as it was possible from extraneous matter. 50 grains grossly 
pounded were exposed, in a platina crucible, to a red heat for 
One hour. They weighed, whilst still rearm, 35-I grains, which 
is a loss of 28^ per cent. 2 5 grains of the same parcel, from 
which I had taken the former, exposed to a heat of longer 
continuance and greater intensity, were diminished in weight, 
at the rate of go-| per cent. 
(2.) The powder still preserved its pure whiteness. It was 
transferred into a matrass, and nitric acid poured upon it, 
which soon began to act upon it. The matrass was placed, 
for many hours, in a digesting heat. A solution of the whole 
