234? Intelligence a?id Miscellatieous Articles. 



'to 



part measured to the edge of the sun's disc (where alone the distor- 

 tion seems to take place), otherwise errors and discordances will 

 occur. Those prodigious lunar elevations and depressions, so fre- 

 quently described in solar eclipses, are seldom or never seen, ex- 

 cept at the commencement or termination of the eclipse, or in places 

 near the solar cusps : that is, in those points only which are near 

 the edge of the sun ; every other portion of the moon's circum- 

 ference being comparatively smooth and circular. If this notion be 

 correct, it would seem that the measurement of the solar cusps 

 during an eclipse may be liable also to discordances from this very 

 cause. 



Mr. Baily concludes, by expressing a hope, that, at the total 

 eclipse of the sun in 1842, and the annular one in 1847 (both of 

 which will be central in Europe), the attention of astronomers will 

 be directed more particularly to this subject, both as to its existence 

 and its cause; and that such a regular system of observations in 

 various places will be adopted, as may best tend to elucidate and 

 explain this very remarkable phaenomenon. 



There was laid on the table, for the inspection of the members 

 present, a small floating collimator, made by M. Amici. This in- 

 strument was only 11 inch in length, and, together with the mercury 

 on which it floats, was packed in a small round box, 2 inches dia- 

 meter in the inside, and 2 inches high, which might be carried in 

 the pocket. It is intended for voyagers, and other persons, to 

 whom a larger instrument would be a great inconvenience. It was 

 the first that had ever been made of such small dimensions. 



There was also laid on the table a drawing, or representation, of 

 several shooting starsy that were observed at Plymouth from the 

 11th to the 14th of November last, together with the direction 

 which they severally took, as compared with the fixed stars then 

 visible. 



II. Stars observed with the moon at the Royal Observatories of 

 Greenwich nnd Edinburgh, and the Observatory of Cambridge, in 

 the month of November, 1 836. 



XL VI I. Intelligence and Miscellaneous Articles, 



ON THE SYMMETRIZING POWER OF THE EYE. BY THE REV. 

 J. G. MACVICAR, A.M. 



To the Editors of the Phil. Mag. and Journal of Science. 

 Gentlemen, 



THE many interesting communications which have appeared in 

 your Journal of late years on the subject of vision induce me 

 to send an account of the following experiment, in the hope that it 

 will not be unacceptable. 



Let the surface of a glass mirror be sprinkled over with some 

 powder, as, for instance, with flour from a dredging box. This 



