March i, 1900] 



NA TURB 



431 



will be in conjunction with the crescent of the new moon at that 

 time, and about 4^ degrees south. 



On reference to my note-book I find that I obtained naked 

 eye views of Mercury on 102 occasions between February 1868 

 and December 1899. But the planet was very rarely looked for 

 here at the morning apparitions, and not always at really 

 favourable spring elongations. If an observer with good sight 

 made it a point to secure as many unassisted eye observations 

 of this object as possible, he might be successful on about twelve 

 occasions in a year. In a finer climate than ours, the planet 

 may, of course, be more frequently seen. I think that some 

 disappointments in regard to finding Mercury are due to the 

 fact that observers scan the heavens at or after the time of 

 maximum eastern elongations, instead of during a week or 

 more preceding them. The phase and apparent brilliancy 

 decrease rapidly at these periods. I have occasionally noticed 

 Mercury as a very brilliant object about ten or twelve evenings 

 before his greatest elongation, while at the date of his elonga- 

 tion he has appeared quite faint, and a few evenings later, 

 become practically invisible, though above the horizon for about 

 two hours after sunset. 



My observations in various years have led me to the follow- 

 ing conclusions regarding the visibility of the planet at the 

 evening apparitions : — 



(i) The greatest brightness of the planet is attained ten or 

 twelve days prior to his greatest elongation. 



(2) In February and March the planet may sometimes be 

 caught twenty minutes after sunset, in April thirty minutes 

 after sunset, and in May forty minutes after sunset. The 

 stronger twilight towards midsummer occasions the difference. 



(3) The duration of his visibility to the naked eye is about 

 ih. 40m. in March, ih. 30m. in April, and ih. 20m. in May. 

 On a very exceptional occasion it is possible these limits may be 

 exceeded. 



(4) The planet is a conspicuous object, and certainly much 

 brighter than a ist mag. star. In February 1868 I considered 

 that his lustre vied with that of Jupiter, then only 2° or 3' 

 distant. In November 1882 he appeared brighter than Sirius. 

 In 1876 he looked more striking than Mars, then 13° distant, 

 but the latter planet was faint and at a considerable distance 

 from the earth. 



The greatest number of naked eye observations of Mercury at 

 the same elongation was obtained at Bristol in the spring of 

 1876, when the planet was seen on thirteen different evenings. 

 When Venus is near Mercury at a favourable time, she affords an 

 excellent guide to the identification of the latter. But errors 

 have often been induced, and either Venus or Jupiter has been 

 mistaken for Mercury on many occasions. In April 1898 Venus 

 was near Mercury, and some people, including a few regular 

 astronomical observers, readily saw Venus and believed (and 

 still ardently believe) that they were looking at Mercury. 



The albedo, or reflecting capacity of the planet, is rated ex- 

 ceedingly low, being only O'li, whereas Mars is 0*27, Saturn 

 0*50, and Venus and Jupiter 0*62. This is remarkable when we 

 consider the occasional striking brightness of the small planet 

 in a region of the sky full of strong twilight. By telescopic 

 comparisons of the disc of Mercury with other planets, it is, 

 however, easily seen that the former is relatively feeble in 

 brilliancy. On May 12, 1890, I viewed Mercury and Venus in 

 the same field of view of a lO-inch reflector, and remarked 

 that the brilliant silvery light of Venus contrasted strongly 

 with the much duller hue of Mercury. The probability is 

 that the latter object is provided with a much thinner atmo- 

 sphere than that which envelops his sister planet. There are 

 undoubted markings visible on Mercury, but they are nothing 

 like the peculiar representations of them which have been 

 published in the last few years. The extreme difficulty of 

 obtaining satisfactory views of the planet furnishes the 

 principal reason why his rotation period still awaits accurate 

 determination. W. F. Denning. 



UNIVERSITY AND EDUCA TIONAL 

 INTELLIGENCE. 

 Oxford. — Junior Scientific Club, February 21.— Mr. II. B. 

 Hartley (Balliol College) read a paper on liquid crystals, and 

 showed, by microscopic demonstration upon the screen, experi- 

 ments with para-azoxyanisol and para-azoxyphenetol which melt 

 •o doubly refracting liquids at 116° and 135° respectively. These 



NO 1583, VOL. 6f] 



remarkable bodies have not previously been shown in England ; 

 the curious transformations which they undergo were made 

 clearly visible to a large audience. 



Cambridge. — A very valuable and interesting collection of 

 Irish antiquities, formed during the [last seventy years by Mr. 

 T. R. Murray, of Edenderry, has been acquired for the Univer- 

 sity by Prof. Ridgeway. It includes unique bronze weapons 

 and ornaments, stone axes and arrowheads, medieval pottery, 

 &c. The collection will be exhibited in the Fitzwilliam Museum 

 on March 5. 



A University Prize for the best M.D. Thesis has been founded 

 in memory of Raymond Horton-Smith, M.A., M.B., late 

 scholar of St. John's College, who, after a distinguished career 

 in the University and at St. Thomas's Hospital, London, died 

 last year at the untimely age of twenty-seven. Candidates must 

 have taken honours in one of the Tripos examinations, and the 

 Prize Thesis is to be printed and circulated. 



The arrangement with Addenbrooke's Hospital, by which the 

 Professors of Physic and Surgery are to have places on the 

 staff, in consideration of an annual subsidy of 300/. from the 

 University, is now submitted for adoption by the Senate. It has 

 already been approved by the Hospital Court, and will probably 

 come into effect forthwith. It puts an end to an old difficulty 

 between the medical school and the hospital. 



The thanks of the University are ordered for certain valuable 

 gifts to the Engineering Laboratory. Lord Kelvin has pre- 

 sented a set of apparatus for electrical measurements, Messrs. 

 Siemens Brothers a pair of coupled dynamos, and the Forward 

 Engineering Company a gas engine. 



The University Lecturer in Chemical Physiology, Mr. F. G. 

 Hopkins, M.B., London, is to receive the honorary degree of 

 Master of Arts. 



The Senators of Edinburgh University have decided to 

 confer the degree of LL.D. upon Miss Eleanor A. Ormerod, 

 in recognition of her services to entomology. 



The Senators of St. Andrews University have resolved to 

 confer the honorary degree of Doctor of Laws upon Prof. 

 Mcintosh, Edinburgh, and Dr. Hugh Robert Mill. 



The Norwich Union Fire Insurance Company have just 

 settled the claim of the West Ham County Borough Council, on 

 account of the damage done in the disastrous fire at the 

 Municipal Technical Institute last October, for the sum of 

 25,100/., the Council retaining the salvage. This sum is 

 expected to cover completely the cost of the reinstatement. 

 The opportunity will be taken to enlarge the Institute, accom- 

 modation having already proved too small for the classes. A 

 new block is to be built to contain the whole of the chemical 

 department. This block will contain two lecture rooms, an 

 advanced and an elementary chemical laboratory, furnace room, 

 combustion room, gas analysis room, balance room, and private 

 laboratory, together with the usual private rooms and store 

 rooms. A small forge and a foundry are to be added to the 

 engineering department. The engine and dynamo laboratory, 

 and the engineering laboratory are both to be enlarged, and 

 extra accommodation will be provided for building-trade classes 

 and for the Women's Department and Art Department, together 

 with several extra class-rooms. The cost of these extensions is 

 estimated at 8000/. The builders are busily engaged on the 

 work of reinstatement, and it is fully expected that both new 

 and old portions will be ready for use at the beginning of the 

 new session in October next. 



A COPY of an address recently delivered by Sir William 

 White, K.C.B., F.R.S., at the Merchant Venturers' Technical 

 College, Bristol, has been received. In the course of his 

 remarks. Sir William White pointed out that what is wanted 

 from the national point of view is increased individuality and 

 intelligence among the workers engaged in manufactures and 

 industries. A good technical institution provides the means for 

 developing these qualities, and in such a college a student can 

 find help and assistance in trying to obtain a fuller grasp of 

 principles, and a better knowledge of fundamental principles 

 upon which to base his own further efforts. An engineer, what- 

 ever his line may be, cannot be completely furnished with the 

 means of carrying on his profession by studying it in the most 

 completely equipped college that could be established ; that is 

 only one portion of his education. Until Technical Colleges came 

 into existence, the system of training that was favoured, with 



