1866.] Astronomy. 567 
appears that the new variable star near ¢ Coronze must have risen 
from below the fifth to the second magnitude in less than four hours, 
if not quite suddenly. 
We have to record the discovery of three new planets. On the 
16th of May, Mr. Pogson, Government Astronomer at Madras, 
discovered a new planet, 114 mag. On the 20th of June, Professor 
Peters, of Hamilton College, U.S., discovered another of the same 
size. On the 6th August, M. Stéphan, Director of the Marseilles 
Observatory, discovered a new planet (in Capricorn), with the new 
telescope of that Observatory. The planet is of the ninth magnitude, 
and was observed in Paris the evening after its discovery. Its 
position on the night of August 7th was R.A. 20h. 52m. 54°23, 
8. D. 16° 43’ 57'" 1, about #ths of a degree north of the ecliptic. 
It was retrograding, having lately passed opposition. ‘The numbers 
of these asteroids will be (87), (88), and ; Mr. Pogson’s hag 
received the name Sylvia; Professor Peters’, the name Thisbe. 
PROCEEDINGS OF THE Roya AstronomicAaL Society, 
In measuring the angles of position of double stars, the most 
careful observers become aware of a tendency to obtain different 
results according as the line joining the centres of the stars varies 
in position. For instance, if the star ¢ Bodt’s (whose angle of 
position is about 40° from a declination-circle and 50° from a de- 
clination-parallel) is measured (i) when sufficiently east of the 
meridian to bring the components nearly into a vertical line, (ii) 
on the meridian, and (ii) when so far west of the meridian that the 
components are nearly in a horizontal position, results will be 
obtained differing always in the same direction, and so pointing 
decidedly to the varying positions of the star as the cause of the 
difference. Mr. Dawes explains a simple expedient for determining 
the amount of error due to such causes, and for correcting results 
thus affected. This is to be done by placing in an ordinary window- 
frame a triangular card, having one side vertical and one horizontal, 
and pierced with holes of varying size, which, taken in pairs, form 
artificial double stars. These may be viewed with a small telescope, 
the results of measures taken when the card is placed on one side 
or the other (of the two at right angles) can be compared, and the 
existence and amount of error thus determined. Mr. Dawes shows 
how the necessity for pursuing sucha plan of observation for oblique 
positions may be obviated by the use of a small prism “attached to 
the eye-piece between it and the eye,”—a contrivance which enables 
the observer to bring a double star in any desired position with 
respect to a vertical or horizontal lime. 
