found in the Shetland Seas. 141 



the trivial name Umbra : but the former seems decidedly prefer- 

 able ; for the latter would certainly tend to perpetuate the con- 

 fusion introduced by the mistake of Linnaeus. 



It may be added, that M. Risso, in his Ichthyology, gives a 

 figure and description of our fish, as a new species of Perca (a 

 genus to which it is nearly allied), calling it P. Vanloo, after a 

 painter at Nice. 



On the Transparence/ of Space. By Dr Olbers of Bremen. * 



VTreatness and smallness in space are relative ideas : we can 

 imagine beings to whom a grain of sand would be as large as the 

 whole terrestrial globe is to us, just as we can represent to our- 

 selves an order of things, in which bodies, surpassing in magni- 

 tude the planets and the sun, would be what the grain of sand 

 is to us. From this very circumstance, it is natural to man to 

 judge of greatness or smallnesfe by means of a scale, the imme- 

 diate or mediate basis of which is found in the dimensions of his 

 own body, or of the bodies which surround him, and which he 

 compares with his own. It is only by the aid of such a proce- 

 dure, that man can estimate magnitudes, and it is thus easily 

 understood why he must consider with astonishment the im- 

 mense proportions of those regions of the universe which gra- 

 dually unveil themselves to his eye, armed with the instruments 

 of art. The distance of the sun from the earth is so great, that, 

 to render it capable of being conceived, it has been attempted to 

 calculate the time that a cannon ball would take in traversing 

 this vast space. But every fixed star is a sun, and the nearest 

 of these stars is at so great a distance from us, that the distance 

 of our globe from the sun dwindles almost into nothing beside 

 it. An innumerable multitude of similar stars, of very different 

 sizes, shew themselves to our unarmed view, from the brilliant 

 Sirius, to the stars of sixth or seventh magnitude ; the presence 

 of which is scai'cely detected by the most penetrating eye in the 

 clearest night. Without doubt, a great number of these small 

 stars appear to us inferior to the others in size, because in fact they 

 are so; but the greater part look so small, only on account of their 



• Bibliotheque Universelle, February 1826. 



