1866. | in a Star in Corona Borealis. 377 
trainless comets. If we add those in this catalogue which may be 
supposed to be new stars, perhaps altogether about twenty of these 
remarkable objects have been recorded during the last two thousand 
years. Since 1670, no new star of sufficient splendour to attract 
general attention has appeared. On April 28, 1848, Mr. Hind 
discovered a star of between the 4th and 5th magnitude, occupying 
a position in Ophiuchus, where previously no star even of the 9°5 
magnitude could be seen. This star has not disappeared, but 
remains of about the 11th magnitude. 
The splendour of all these objects was temporary only. Ina 
few days, or weeks, or months, they had waned to a great degree 
of faintness, and were supposed to have become extinct. Whether 
they really ceased to exist, or merely became invisible to the naked 
eye, appears to be uncertain. 
For centuries the intensely interesting questions have agitated 
the minds of the more thoughtful of mankind. What are these 
strange objects ? To what cause can the great but very transitory 
splendour of these stars be ascribed? Are they new creations, 
celestial ephemere, born to die? Are these new stars merely the 
more remarkable and extreme examples of the large class of stars 
which wax and wane in accordance with a special period of 
variation ? 
Tycho Brahe had the good fortune to witness the apparition of 
the most brilliant of these objects, the celebrated star of 1572. 
This star, when it first appeared, surpassed in brilliancy Sirius, 
Vega, and Jupiter, and could be compared alone to Venus when 
nearest to the earth ; within seventeen months the star had become 
invisible to the naked eye. Telescopes had not yet been in- 
vented. 
The star of 1604, at its first appearance, surpassed the stars of 
the first magnitude, and also Mars, Jupiter, and Saturn; but 
Kepler considered that it was not equal in brilliancy to Venus. 
This star became invisible after about fifteen months. 
Tycho Brahe believed that the star of 1572 had been formed by 
the agglomeration and condensation of a portion of the nebulous 
matter diffused through the universe. The Aristotelic philosophy, 
which then swayed men’s minds, prevented the reception of a theory 
which was not in accordance with the absolute perfection of the 
heavens. The phenomena of the sudden splendour and. rapid 
waning of these stars were sought to be explained on the suppo- 
sition that no real change occurs in the star, but that it suddenly 
advances towards the earth with extreme rapidity, and then retraces 
its steps until it vanishes in the remotely distant region from which 
it had emerged. No words are needed, now that the velocity of 
light is known, to show that this hypothesis must be rejected. 
2c 2 
