and Union of Supposed Distinct Species. 303 
cording to his method of determining the atomic proportions, 
Phyllite is a simple silicate, (the atoms of silica and bases 
being equal,) consisting of nine atoms silicate of alumina, three 
atoms silicate of peroxide of iron, three atoms silicate of man- 
ganese, and one atom silicate of potash.' The occurrence of 
so large a proportion of potash in the mineral is not a little 
remarkable, and I would suggest whether it may not have 
been derived from the gangue of slate, from which it is difh- 
cult to obtain the mineral entirely free. Its infusibility before 
€ blowpipe would seem to show this. It has been suggested, 
also, that a part of the iron may have been in the state of 
protoxide. It seems impossible, without some such supposi- 
tion, that substances, so closely resembling each other in all 
their physical characters, should differ so much in chemical 
Composition. Now, if the potash be left out, and the peroxide 
of iron be changed into protoxide, the ratio between the atoms 
of acid and bases is nearly the same as in Ottrelite, if we unite 
the atoms of magnesia and iron, as isomorphous with each 
other, Ottrelite, also, is not easily separated from its matrix, 
but the larger size of its plates would seem to render it more 
easy to obtain pure specimens for analysis ; and it is to be ob- 
Served that Damour repeated his analysis, and obtained pre- 
cisely the same result. It is remarkable that Rammelsberg 
has alphabetically inserted Phyllite, but has given no formula 
lor its constitution. It seems proper that the name of Phyllite, 
on the ground of its priority, and because it expresses so well 
the ordinary appearance of the mineral, should stand, and that 
of Ottrelite be abandoned.’ 
Dysluite identical with Automalite. 1 am satisfied, from 
recent observations, that these two minerals, as they occur in 
New Jersey, should form but one species. The difference in 
? Outlines of Mi ; . Dr. Thomson's atomic weights, 
founded upon e d E ds pie multiples of the atomic weight of 
Ydrogen, vary somewhat from Berzelius's. à : ‘ BU senis 
the a € has supposed Phyllite to be identical with Gigantolite. t ii den. 
c analysis of Gigantolite with Damour's analysis above, the evidence of their iden 
JY (supposing Ottrelite to be a purer variety of Phyllite) is much more marked, 
. the atoms of acid and bases is nearly the same in 
