364 Miscellanies. 



The metals oxidize rapidly in water ; are brittle, fixed, and require 

 a good red heat for fusion. They sink in sulphuric acid. By keep- 

 ing in naphtha, they acquire a coating which renders them less active 

 when exposed to water. 



Dr. Hare attempted to separate the mercury from the amalgams 

 when solidified by the use of solid carbonic acid, by straining them 

 through leather, but the result did not answer his expectations. 



By using solid carbonic acid and hydric (sulphuric) ether. Dr. Hare 

 solidified a mass of the amalgam of ammonium. He considers that 

 in this case a portion of ether combines with the alloy, without im- 

 pairing its metallic character. 



Professor Bache, in behalf of Professor Alexander, of Princeton, 

 made a verbal communication of a description of the aurora borealis, 

 of September 3d, 1839, as it appeared at Princeton. 



At about ten or fifteen minutes past eight, P. M. an ill-defined, but 

 considerably bright light was seen to extend for some distance above 

 the horizon, in a direction nearly due east ; it was similar, in intensity 

 and appearance, to a lunar twilight. Soon after this, a continuous 

 arch or zone of light was manifest, extending from the same spot to 

 the opposite, or nearly opposite portion of the western horizon. This 

 soon separated into two parts,* and, after a short interval, beams of 

 light shot up from the eastern portion of the arch, which were speedily 

 multiplied in every direction around the observer, except within about 

 thirty degrees of the true (or it might be magnetic) south. 



A corona was soon formed, which was at first quite indistinct, and 

 was not continuous for any great length of time, during the existence 

 of the aurora, except at the period of its greatest brilliancy. At about 

 twenty minutes past eight, this corona was situated in a line with, and 

 about midway between a Aquilae and a Lyrae. This may be consider- 

 ed as a very tolerable approximation to its position, though, from the 

 apparent intersection, or, as it might almost be termed interweaving 

 of the beams which composed it, it was not often easy to fix upon the 

 place of its centre with much precision, if indeed that which seemed 

 its centre, did not really change its place ; since, at times, it seemed 

 to occupy a position very sensibly lower than that which the prece- 

 ding observation would indicate. 



At about half past eight, the appearance of the aurora was superb. 

 The radiations which extended from the corona, nearly reached the 

 horizon in every direction, with the exception of those which tended 

 toward the southern space before-mentioned, which, it is believed, was 



* Two arches, it is believed, were at this time formed, and either separated 

 throughout their entire extent, or united only near their extremities ; but this ray 

 notes do not explicitly state. 



