perturbations, &c. 
Intelligence and Miscellaneous Articles. 173 
M. BREITHAUPT’S MINERALOGY. 
In No. 27 of this work we noticed two varieties of wavellite from 
Frankenberg, and stated, upon what we now find to have been in- 
accurate information, that they had been named by M. Breithaupt 
Peganit and Pegmatit. This latter name should have been Sérigisan. 
We have since had an opportunity of examining another of this gen- 
tleman’s new minerals, his Arsenic Glance, which appears to con- 
sist of native arsenic and galena in distinct and unmixed layers. 
A specimen, said to be his Batrachite, has also been brought to us ; 
but it seems to be only an amorphous mass of a grayish rock, without 
any definite mineralogical character ; and possibly many more equally 
good species might be afforded from the same locality. 
We cannot but regret to see an already overloaded nomenclature 
thus encumbered with new names representing nothing that can ever 
‘yank as distinct minerals. The alumocalcite of this author is another 
instance of considering accidental varieties of known minerals as new 
species; and the specimen in situ of his erlanite, from which the 
fragment that has been analysed was taken, is said to be some miles 
in extent, and at least 100 fathoms in thickness. ‘The Andes might 
afford a copious harvest of such simple minerals as this.—EbirT. 
HALLEY’S COMET. 
This interesting body has been twice seen since its perihelion pas- 
sage by the Rev. R. Dawes, of Ormskirk, on the 16th and 19th in- 
stant. On the 16th its place was noted, and found to be, January 
15,785, 1836, Greenwich, mean time, R.A, comet 15h. 59 min. 46: sec. 
south declination 27 deg. 22 min. 30sec. These values will require 
some further correction, and the declination is considered to be an 
approximation merely, On the 19th the haze only gave time for a 
casual glimpse. As the comet is said by Mr. Dawes to be “‘ exceed- 
ingly faint”, itis hopeless to look for it with any telescope which does 
not considerably exceed his in power—that is, a very excellent five- 
feet telescope, made and mounted by Dollond. Mr. Dawes is acknow- 
ledged to be one of the most skilful and delicate measurers of minute 
‘celestial phenomena in this country, and has contributed several 
valued memoirs to the Royal Astronomical Society. By interpolat- 
ing from Lieutenant Stratford's admirable ephemeris of Hatiey’s 
comet, for the moment of Mr. Dawes’s observation, the place is found 
to be R.A. 15h. 59 min. 43°5 sec. south declination, 27 deg. 22 min. 
42 sec., a very near coincidence, especially when it is remembered 
that the ephemeris only pretends to: be approximate, is founded on 
unreduced observations, and is not as yet corrected for planetary 
ON SESQUISULPHATE OF MANGANESE. BY DR. THOMSON, 
When neutral solutions of sulphate of zinc and chloride of manga- 
nese are mixed together, no sensible change takes place. But if tne 
mixture be concentrated, it gradually deposits yellowish white co- 
