400 J. W. Mallet on Sipylite, a new Niobate. 
R” MYO, . R’,M$O,, and Rammelsberg ware »yrochlore 
from Fredriksvarn solely the pyro-niobate, R I0,, and 
fergusonite, tyrite, es soley. the ortho-salt, R’’, 
owever, the water be included in the Paice and 
considered basic, alas it on an equivalent footing with the 
dyad oxides we have the ratio, 
R’O;: MSO. = 311: : 100, or nearly 3:1, 
which gives the simple formula of an ortho-salt, R”,M‘O,. 
This I confess I am inclined to think more probable, and, if so, 
it may be allowable to suppose that the very remarkable glow 
exhibited by the mineral when heated is connected with the 
loss of basic water and the change from ortho- to pyro-niobate, 
as in the well known incandescence of ammonio-magnesian 
ortho-phosphate at the moment of change by heat to the pyro- 
phosphate of the latter metal.* 
Whichever formula be preferred, sao hus for the mineral 
now described, it differs essentially fro that of any niobate 
hitherto on neon, the one view aking it the nearest approach 
to a simple pyro- -niobate (since the Fredriksvarn pyrochlore con- 
tains largely of titanium) and the other making it an ortho-salt 
ike fergusonite, etc., but one partially acid in character or 
penne basic h drogen 
5 heey grounds alone, but in several respects as to 
eg properties, the mineral is new and distinct. Carrying 
out the fancy of Heinrich Rose, which led him to name niobium ~ 
from the danghter of Tantalus, and remembering the number 
and SUEY of the natural niobates which have been met 
with, Foe a for this species the name sae dine from Sipylus, 
one of the numerous children of Nio 
*Tt cade: aye worth remarking that from the nae of Professor Allen (loc. cit.) 
of Professor J. Lawrence Smith’s ele coal tchettolite, which accompanie 
samars' kite i in North ats sears water resent in it in definite leo 
tion; and, although Rammelsberg ~g waa aa the water found in his analyses 
of tantalates and niobates as non-essential, and the formula, R’’, MYO,, which he 
has assigned in common to ge gene nite, yttro-tantalite, eg and bragite, requires 
that bsg’ be e seluden: if it be also taken into account his analyses of these 
minerals lead pretty closely to her acgtelh eno ns as to ee extent of hydration 
(without considering the water basic), mak 
Fergusonite, from Gree: rset (with very ties water)—R’’,MYO,, 
or perhaps 2R’’,MYO, 
Brown yttro-tantalite, from Yiterby 
“ 
Bragi 
ae ciccua from Gamle Kararfvet_........--- 2R/’,MYO, . 5H, 0. 
University of Virginia, Sept. 3, 1877. 
