A C08M0SC0PE. 103 



the whole of the streaked and radiated corona occupying a region twenty 

 times greater than the globe of the sun (which itself exceeds our earth one 

 million two hundred and fifty thousand times in volume) belongs to the sun. 

 Again, though the sun has shone steadily for thousands of years, yet, so 

 far as can be judged, the stars which, like this one in the Swan, have burst 

 out suddenly, blossoming into flames of hydrogen, within which the star's 

 heart core glows with many hundred times its former heat, have also been 

 for ages shining steadily amid the star depths. We know that the one 

 which blazed out ten years ago in the Northern Crown was one of Arge- 

 lander's list, a star of the tenth magnitude, and that, after glowing with 

 eight hundred times its former brightness for a few days, it has resumed 

 that feebler lustre. We have every reason which analogy can furnish for 

 believing that the new star, which was not in Argelander's list, simply es- 

 caped record by him on account of its faintness. It is now fast losing its 

 suddenly acquired lustre, and is already invisible to the naked eye. It ap- 

 pears, therefore, that there is nothing in the long-continued steadfastness 

 of our sun as a source of light to assure us that he, too, may not suddenly 

 blaze forth witli many hundred times his usual lustre (the conflagration 

 being originated, perchance, by some comet unfortunately traveling too di- 

 rectly towards him). Though he would probably cool down again to his 

 present condition in the course of a few weeks, no terrestrial observers 

 would be alive at any rate to note the fact, though the whole series of events 

 might afford subject of interesting speculation to the inhabitants of worlds 

 circling round Sirius or Arcturus. Fortunately we may legitimately reason 

 that the risk is small, seeing that among the millions of suns which sur- 

 round ours, within easy telescope distance, such catastrophes occur only 

 ten or twelve times per century." 



In addition to the chances in our favor that our sun will not be the next 

 one to blaze forth like that above described, Professor Loomis, of Yale 

 College, explains that such variations in the brightness of stars are not 

 very unusual nor very infrequent, and that while the cause of these phe- 

 nomena, yet a matter of conjecture among astronomers, is pi-obably the 

 falling of some aerial vanderer, like a comet or a meteor, into the fixed star 

 and its consequent rapid combustion, such an event need produce no se- 

 rious results necessarily, since it is a commonly received theory that the 

 continuous intense heat of the sun is caused by the constant accession of 

 such combustible and inflammable bodies. 



A COSMOSCOPE. 



Last Monday evening Prof. C. B. Boyle exhibited before a few promi- 

 nent members of the American Geographical Society a very ingenious in- 

 strument of his own invention, which shows the precession of the equi- 

 noxes, the portions of the globe which are illuminated by the sun at all 



