366 ANNUAL OF SCIENTIFIC DISCOVERT. 



inches aperture, of my own manufacture, and though the mirrors have 

 since been much tarnished, and the instrument otherwise injured, its 

 performance is incomparably superior to what it was in America. 

 Venus sometimes shines with a light so dazzling, that at a distance of 

 thirteen feet from the window I have distinguished the hands of a 

 watch and even the letters of a book. Some few months since, having 

 met with the statement that the satellites of Jupiter had been seen 

 without a glass on Mount Etna, it occurred to me that I was in the 

 most favorable circumstances possible for testing the power of the 

 unassisted eye, and I determined at once to make some experiments 

 on the subject. My attention was, of course, first turned to Jupiter, 

 but for a considerable time with no success. It was always so bright, 

 and shot out so many rays, that it seemed quite impossible to detect 

 any of its moons, even at their greatest elongation from the planet. 

 I varied the experiment in several ways, by looking through the tube 

 of a small telescope, from which the lenses had been taken, and also 

 by placing my eye near the corner of a building, so as to cut off the 

 most brilliant rays of the planet, and yet leave the view unobstructed 

 to the right hand or the left ; but in neither case could I find any 

 satellite. Some time after, I was sitting on the terrace as daylight was 

 fading into darkness, and thought I would watch Jupiter from its first 

 distinct appearance till it shone out in its full splendor. This time I 

 was exceedingly gratified, just as stars of the first and second magni- 

 tude were beginning to appear, to see two extremely faint points of 

 light near the planet, which I felt sure were satellites. On pointing 

 my telescope towards them, my first impressions were confirmed, and 

 I almost leaped for joy. Since that night I have many times, at the 

 same hour of the evening, had a similar view of these telescopic objects, 

 and think I cannot be mistaken as to the fact of their visibility. I 

 must, however, add that none of my associates, who at my request 

 have attended to the subject, are sure that they detect them, though 

 the most sharp-sighted individual feels some confidence that he can 

 do so. As these friends, however, are not practical observers, their 

 failure to see the satellites does not shake at all my belief that I have 

 seen them myself. The time during which these satellites are visible 

 is hardly more than ten minutes. The planet itself soon becomes so 

 bright that they are lost in its rays. I will not stop to discuss the 

 question, in itself a most interesting one, why they are visible at all, 

 when stars of the third and fourth magnitude are not distinguishable, 

 but merely give the facts in the case, knowing that you will reason on 

 them far better than I can. Both the fixed stars and the planets shiive 

 here with a beautifully steady light, and there is little twinkling when 

 they are forty degrees above the horizon. Having come to a satisfac- 

 tory conclusion about the satellites of Jupiter, I turned next to Saturn. 

 This planet rose so late in the night, that I had not seen it while 

 watching Jupiter, and I was very curious to know whether any traces 

 of a ring could be detected by the naked eye. To my surprise and 

 delight, the moment I fixed my eyes steadily upon it, the elongation 

 was very apparent, not like the satellites of Jupiter, at first suspected, 





