Disturbance of the Earth’s Magnetism. 143 
Chlorovinite of lime is in the form of hexagonal prisms, generally 
tr ometimes pyramidically terminated: colorless and 
transparent, brittle, cross fracture even, permanent in the atmosphere 
nd unalter ight. In dry air the crystals become opake and 
gray fused mass, composed of chloride of calcium, carbonate of lime 
and carbon remains. In pure alcohol, they lose water and slowly dis- 
solve; a hot saturated solution, deposits crystals on cooling. In water 
there is a white precipitate which becomes crystalline, and is partially 
soluble in water. With solutions of copper, chlorides of sodium, ba- 
rium and potassium, the resulting salts are soluble. Oxalic acid 
eliminates the acid and forms a white oxalate of lime. 
(To be continued.) 
Arr. XVI.—On a disturbance of the Earth’s magnetism, in con- 
nexion with the appearance of an Aurora Borealis, as observed at 
Albany, April 19th, 1831; by Josern Henry, of the Albany 
A my. 
[Communicated to the Albany Institute,” January 26, 1832.] 
Tuar the aurora has some connexion with the magnetism of the 
confirm this position. 1. It has been observed, that when the au- 
rora appears near the northern horizon in the form of an arch, the 
middle of this is not in the direction of the true north, but in that 
of the magnetic needle at the place of observation; and that wi 
the arch rises towards the zenith, it constantly crosses the heavens 
at right angles, not to the true, but to the magnetic meridian. ‘This 
fact is most obvious where the variation of the needle is great. 
* And forwarded for insertion in this Journal. 
