75 
SCIENTIFIC SUMMARY. 
ASTRONOMY. 
A NFB TJLA suspected to be nearer to us than certain Fixed Stars. — Mr. 
Le Sueur has studied the celebrated nebula around rj Argus with the 
fine four-feet reflector by Grubb, recently sent out for the Melbourne Obser- 
vatory. He finds no reason to suspect that any of the stars mapped by Sir 
John Herschel have changed either in situation or in brilliancy. But the 
nebula shows so many indications of change, that he has been led to the 
opinion that it lies nearer to us than the fixed stars seen in the same field of 
view. It need hardly be said that he expresses merely the view suggested 
to him by the appearance, and changes of appearance, of the nebula. There 
are no means whatever of determining whether the nebula is nearer to us or 
farther from us than the stars with which it seems associated. It is, how- 
ever, possible, that if the nebula is really associated with those stars, the fact 
may be recognised by peculiarities in the apparent movements of the nebular 
masses. It seems difficult to study Sir John Herschel’s pictures of the irre- 
gular nebulae without being led to the opinion that stars and nebulae are 
actually mixed up together. It will be interesting to learn whether Mr. 
Le Sueur’s pictures of the great nebula cannot be explained as due to motions 
of the nebular masses around the stars. His present opinion is, however, 
that we have mentioned above. 
The discovery is interesting, coming, as it does, so soon after the enuncia- 
tion by Mr. Proctor of the theory that nebulae are not external galaxies, 
but belong to, and fall within, the sidereal system. 
Sir John Herschel, commenting on this view, remarks that possibly the 
nebulae may be miniatures of our galaxy within its limits. 
Method of correcting the Atmospheric Chromatic Fispersion. — The Astro- 
nomer Royal has invented a means of correcting the annoying appearances 
arising from the chromatic dispersion produced by the atmosphere. When 
observing the recent transit of Mercury, he was painfully struck with the 
colour and consequent indistinctness of the upper and lower limbs, both of 
the sun and of Mercury, suggesting the prospect of a total loss, in the obser- 
vations of the transits of Venus, of that delicacy on which the success of the 
observations will greatly depend ; “ it being remarked that for the most 
valuable observations, the sun must be low, and the atmospheric refraction 
and dispersion must therefore be considerable ; and, further, that the planet 
must be near the highest or lowest part of the sun’s limb.” He has found 
