154 Van Mons. 
whether any or what coincidence there may be between this pla- 
nisphere and the zodiac referred to. We shall be happy to re- 
ceive from any of our correspondents whatever rational conjec- 
tures may occur to them respecting the planisphere. To us it 
appears that it has reference to a period at which Taurus, Leo, 
Scorpio, and Aquarius, were the cardinal! signs; for these signs 
are made to coincide respectively with tue four corners of the 
apartment: but this settles nothing as to the time at which it 
was setup. We shall only throw out the suggestion (which 
may yet be very foolish), whether something relative to the pre- 
cession of the equinoxes is not indicated by the overlapping, as 
it were, of some of the signs? We are aware that the duplicates 
ef Taurus and of Leo have been considered as extra-zcdiacal 
asterisms ; but may they not be intended to mark a difference 
between the moveable and fixed zodiacs?>—between the ideal 
zodiac, which astronomers. always make to commence with the 
veruai equinox, still calling the first 30° ries, and the stellar 
constellation originally so called? If so, Taurus seems to be 
inarked as the vernal] equinox at a period much more ancient 
than the date of the erection of the temple of Dendera; and if 
so, by the motion of Taurus in the moveable zodiac, when the 
equinox had changed a whole sign the moveable Gemini would 
come to the place of the stationary Taurus, aud so of the other 
signs, making Aries to become the vernal sign: and by a second 
change of a whole sign the moveable Taurus would reach the 
stationary Pisces, bringing the moveable Liéra to the stationary 
Leo. Is this indicated i in the eee before us? If so, the 
vernal equinox at the time when this planisphere was put up 
appears to have been in the steliar Pisces, which it is now quitting. 
The precession of the equinoxes, as it is called, is at the rate of 
about 214 centuries for one sign. 
Letter from M. Van Mons, dated Brussels, Fel. 10. 
‘It is said that Berzelius has made some decisive experi- 
ments on chlorine, and on the quantity of oxygen which it con- 
tains. I think that after mine his proof was not necessary : 
and what in fact could we wish for stronger than sweet mercury, 
which in 100 of oxidule which it contains, gives four of oxygen 
and corrosive sublimate; which on the same quantity of oxide 
The zodiac of the portico, and the dissertation of Dr. Henley, of course 
were mentioned; and Mr. Taylor, remarking: that the plate of the plani- 
‘sphere was 20 well engraved, that it could bear printing off a sufficient 
wnmber for the Philosophical Magazine, as well as for the expensive work 
which he is now publishing, added that he should be pleased to see it in the 
work in which Dr. Tenley’s Dissertation had appeared, as it might then 
aicet the eyes of some who have already paid attention to the subject. 
gives 
