5° in length in the illustration of November 16 appeared subsequent to the exposure of November 15. At any rate, there is no streamer on the earlier plate with which it can reasonably be identified. If we assume that matter has been ejected to a distance of 5° in one day, the average velocity of recession from the nucleus is greater than ninety miles per second, for ninety miles per second is roughly the velocity in the direction of the tail projected upon a plane at right angles to the line of sight. That the phenomenon is an effect of rotation is also difficult to conclude. Photographs taken at other observatories during this interval would help solve the problem.

Without doubt, the comparison of plates will show acceleration in the motion of recession from the head. One such rough measure has been made from a reproduction of a photograph1 taken at the Observatory of Juvisy on October 16th, 7h 45m, Paris Mean Time, and two photographs taken at the Lick Observatory, October 16th, 10h 20m, and October 18th, 7h 58m, Pacific Standard Time. Approximate measures were made on the broadening of the tail. The distances on the three plates are 10.5, 1°.9, and 4°.3. The resulting average velocities of recession from the head in the direction of the tail are twentyseven miles (44km) and thirty-six miles (58km) per second for the first and second intervals, respectively.

Much work remains to be done, and the detailed results will be published in a subsequent Lick Observatory Bulletin.

LICK OBSERVATORY, January 28, 1909.

1 Comptes Rendus, 147, 1035.

There will be two eclipses during June.

The first is a total eclipse of the Moon on June 3d, and it will be visible in part at least over the United States, except the extreme western portion. For the extreme eastern states total eclipse begins shortly before sunset, while for the states along the Pacific Coast the eclipse will be about ended at

sunset.

The second is a central eclipse of the Sun on June 17th, the line of central eclipse running from Siberia across the Arctic Ocean and south through Greenland. On the central line it is an annular eclipse at the beginning and end of its path and a total eclipse in the middle part. It will be visible as a partial eclipse in the late afternoon throughout the United States, except that part south of a line running from San Francisco southeast into the Gulf of Mexico. The local times for beginning and end at Ogden, Utah, are 4h 48m P.M. and 6h 3m P.M.

The summer solstice, the time when the Sun reaches its most northerly point, occurs June 21st, 6h P.M., Pacific time.

Mercury passed superior conjunction with the Sun on Apri! 1st and became an evening star, and will remain an evening star until June 14th, when it passes inferior conjunction and becomes a morning star. The month of May affords the best time of the present year for seeing the planet. On May 1st the interval between the setting of the Sun and of the planet is just about one hour, and this interval rapidly increases as

the planet moves out toward greatest east elongation. It is increased by the circumstance that the planet is in the northern half of its orbit, reaching greatest heliocentric latitude on May 9th. By the middle of the month the planet does not set until nearly two hours after sunset. Greatest eastern elongation is reached on May 20th. The distance from the Sun is then 22° 23′, about an average greatest elongation. After greatest elongation the planet and Sun approach each other, but on June 1st the planet will not set until an hour and a quarter after sunset. It will therefore still be visible in the early days of June. After passing inferior conjunction on June 14th the distance between planet and Sun increases rapidly, so that by the end of the month the planet rises about an hour before sunrise.

Venus became an evening star on passing superior conjunction April 28th, and will remain an evening star until after the close of the year. On May 1st it sets only two minutes after sunset and remains too near the Sun for nakedeye visibility until after the middle of the month, and until the middle of June it sets less than an hour after sunset. It will not be a conspicuous object until autumn.

Mars rises at about 1h 40m A.M. on May 1st, and at about 11h 30m P.M. on June 28th. It moves about 36° eastward and 12° northward, from Capricorn through Aquarius into Pisces. Its distance from the Earth diminishes from 104,000,000 miles on May 1st, to 64,000,000 on June 30th, and its brightness nearly trebles during the two months. It is, however, at the end of June only one third as bright as it will be at opposition in late September.

Jupiter is in fine position for evening observation, being above the horizon on May 1st until about 2h 30m A.M. It sets earlier as the month advances, but remains above the horizon. as late as 10h 40m P.M. on June 30th. It is stationary among the stars on May 1st, but begins to move slowly eastward, gradually increasing its rate until by the end of June it is nearly 5° east and 2° south of its position on May 1st.

Saturn became a morning star early in April. By May 1st it rises not quite an hour before sunrise, and by June 30th it rises about half an hour after midnight. It is in the constel

lation Pisces and moves about 5° east and 2° north during the two months.

Uranus rises shortly after midnight on May 1st, and shortly after 8 P.M. on June 30th. It is in Sagittarius, east and north of the bowl of the "milk-dipper," and moves somewhat more than 1° westward during the period.

Neptune is in Gemini and is in the western sky in the evening. Venus passes a little less than 2° north on the evening of June 22d.

NOTES FROM PACIFIC COAST. OBSERVATORIES.

ORBITS OF THE BINARY STARS 55 Tauri, π2 Ursæ Minoris, AND 4 AQUARII.

The orbit of 55 Tauri (= O 79) was first computed by HUSSEY in 1901, but at that time there was still great uncertainty as to the form of the apparent ellipse, and the one on which his elements were based will not fit the more recent observations. The range of uncertainty is now much smaller, and it is hoped that the following elements will prove to be approximately correct. They are:—

No orbit has heretofore been published of the binary star 2 Ursa Minoris (= Σ 1989), although the angular motion since discovery in 1832 exceeds 270°. This is mainly due to the uncertainty attaching to the early observations. The following elements give satisfactory residuals for these observations, as well as for the more reliable of my recent measures made when the angular separation of the two components was less than o'.10. Nevertheless the results must be regarded as subject to a large degree of uncertainty. They are: