Observations on the Meteors of the 12 th of November, 85 



And as to what concerns the density, calculated according to 

 the same formula, we find 



1 vol. of chrome 3*8811 



2 vol. of chlorine ... 4-8920 

 2 vol. of oxygen 2-2078 



10-9809 



= 5-49 



2 



But here each atom of the compound represents only two vo- 

 lumes of vapour. This body may therefore be regarded as a 

 distinct acid, which might be named chloro-oxi- chromic acid. 

 Recollecting that the perchloride of chrome does not exist in 

 an isolated state, that analogous compounds are only produced 

 by acids, which for one atom of radical contain three atoms 

 of oxygen, which are isomorphous with each other, and which 

 may all be expressed after the hypothesis of M. Persoz, by 

 the formula R O^ + O, in taking into consideration the facility 

 with which this body is decomposed when brought into con- 

 tact with other bodies, and its little stability ; this manner of 

 regarding the constitution of this body, which explains its va- 

 rious actions, offers the appearance of much probability. 



XVIII. Observations on the Meteors of the I2th of November, 

 Communicated by Prof Forbes.* 



A COMMITTEE appointed by the Physico-Mathematical 

 ^ Society (University of Edinburgh) were employed on the 

 nights of the 12th and 13th of November, in watching for the 

 annual fall of meteors, expected to take place about that time. 

 During the earlier part of the night of the 12th there was a 

 fine coloured Aurora : at 7** 30"", a red arch extended from E. 

 to W. passing about 15° S. of the zenith and within 15° of the 

 full moon. This continued with slight variations till 9^ when 

 it stretched from E. to SW., there being a beautiful red spot 

 at the point of radiation a little S. or SE. of the zenith. The 

 red colour continued with variations till 10*^ 15™, when the 

 whole northern half of the sky was covered with bright greenish 

 streamers. Soon after the sky became covered with clouds and 

 mist, through which the brightest stars only were visible. 

 There was scarcely any wind. Till late in the morning no 

 meteors of any importance were seen. At 9^ 35"^ one meteor 

 shot from E. toward NNE., and at 10*^ 20"^ another from the 

 zenith along meridian. At 0*^ 25™ one passed from NNW. 



♦ See our last volume, pp. 261, 567. 



