The computations and some of the observations in the following notes are from students in the astronomical department. The times of risings and settings of planets are approximate, but sufficiently accurate to enable an ordinary observer to find the object mentioned Positions of Planets for May, 1871. Mercury. On May 1, Mercury rises at 5h. 49m. A.M., and sets at Sh. 49m. P.M. It can be easily seen in the first half of the month, especially on the 3d, when it has its best position. At that time it sets about S north of the point of sunset. On the 31st, Mercury rises at 4h. 23m. A.M., and sets at 6h. 23m. P.M. Venus. On May 1, Venus rises at 5h. 1m. A.M., and sets at 6h. 44m. P. M., too nearly with the sun to be seen. On the 31st, Venus rises at 4h. 57m. A.M., and sets at 7h. 55m. P.M. Venus may perhaps be seen after sunset at the last of the month, as it sets a little north of the sunset point. Mars. Mars rises on May 1 at 1h. 23m. A.M., and sets at 10h. 55m. A.M. On the 31st, Mars rises at Oh. 18m. A.M., and sets at 10h. 26m. A.M. Mars is among the stars of Gapricornus, and, although small, is very readily known by its ruddy color. Jupiter. Jupiter is very brilliant in the morning. It rises on the 1st at 11h. 2m. P.M., and setss at Sh. 4m, A.M. cf the next day. On the 31st, Jupiter rises at Sh. 54m. P.M., and sets at 5h. 56m. the next morning. On May 3, only three of the satellites of Jupiter will be seen when it rises, one of them being in transit across the disk of the planet. On May 5, only three satellites will be seen before midnight, the smallest being in transit across the disk. On the 21st, when Jupiter rises, only three satellites will be seen, as one of them is in the shadow of the planet, or is eclipsed, On the 25th, the largest satellite cannot be seen in the evening, being behind the planet. A good opera glass, an ordinary ship's glass, or a small telescope will show these moons of Jupiter. Saturn. On May 1, Saturn rises at 3h. 2m. A.M., and sets at 2h. 15m. P.M. It can scarcely be seen at all. On the 31st, Saturn rises at lh. 9m. A.M., and sets at Oh. 27m. P.M. At this time it can be seen for a few hours in the morning. It is among the stars of Aquarius. Uranus. On May 1, Uranus rises a few minutes before noon and sets at lh. 49m. the next morning. On the 31st, Uranus rises at 10h. A.M., and sets at 11h. 52m. P.M. It is still among the stars of Leo. Sun Spots. From March 16 to April 15 the sun has been unusually free from spots, even for thisminimum period. B ut two groups have been seen, the first composed of two small spots, on March lS, and the second, a large group, on Aprit 15. A peculiar interest attaches to them, however, as they seemed to appear suddenly near the middle of the sun's disk. No spots could be seen on April 14, yet on the 15th a double spot of large size, surrounded by several smaller ones, is found near the center, seeming to show a sudden disturbance in that region. The Comet. On the morning of April 15, the small comet, just visible to the eye, was very near the star 32 Pegasi, and moving slowly toward the north. It had a bright nucleus, and could be seen with a glass until just before sunrise. It is increasing in brightness. The train is broad, and up to April 15 not more than a degree in length. Substitute for Sulphate of Quinine. Dr. Woodworth, Supervising Surgeon-General, calls the attention of medical officers of the U. S. marine hospital service to the extraordinary increase in the market price of quinia sulphate, and at the same time to the accumulating testimony in favor of the employment of the quinidia, chin- chonidia, and chinchonia sulphates, of which the two first named are believed to be as efficacious as the quinia sulphate. He suggests that the less costly salts be accorded a fair trial, and that medical officers take this matter in consideration in preparing their next semi-annual requisition for medical supplies. < <II A. K. S. writes to say that strong draught is indispensable in a coal oil lamp, and that there exists a demand for a flat- wicked lamp with an argand chimney, which will supply the I draught necessary to give perfect combustion. 1877 SCIENTIFIC AMERICAN, INC.