390 



NA TURE 



[August i8, 1904 



other, by Mr. C. Reid, announcing the discovery in the 

 " elk-marl " of Lough Gur of remains of the submerged 

 flowering plant Naias marina. The new liverwort, 

 curiously enough, appears to be very similar to a species 

 from Tierra del Fuego. The Naias, we may remind our 

 readers, is now found living only in one spot in Great 

 Britain, namely, Hickling Broad, but has been found fossil 

 in several localities, although it was hitherto totally un- 

 known in Ireland. 



Several pamphlets dealing with forestry problems have 

 been received from the United States Department of Agri- 

 culture. Discussing the future supply of railroad ties, Mr. 

 H. von Schrenck, in a Bulletin, shows that timber of 

 inferior quality is rendered as durable as that of a better 

 quality by treatment with suitable preservative substances. 

 A recent process, which is still in the experimental stage, 

 makes use of a strong sugar solution in which the timber 

 is boiled. With the adoption of softer timber, the method 

 of fastening the rails requires consideration, and the re- 

 spective forms of spikes, plates, and dowels are con- 

 trasted. In a Bulletin on the planting of white pine, Mr. 

 H. B. Kempton compares the results obtained on four 

 different woodlots, from which it is concluded that the 

 expense of laying out a pure white pine plantation is con- 

 siderable, but this may be reduced by planting less expensive 

 seedlings, such as sugar maple, between, and these are cut 

 down when thinning is required. 



" A Critical Revision of the Genus Eucalyptus " is the 

 title of a memoir by Mr. J. H. Maiden, director of the 

 Sydney Botanic Gardens, which has reached the fourth part. 

 Two species, Eucalyptus incrassata and Eucalyptus 

 foecnnda, with varieties, are described and figured in a 

 number of plates. 



The extension section of the Manchester Microscopical 

 Society has just issued an attractive list of popular science 

 lectures (fifty-four in all) which have been arranged for 

 delivery by its members during the coming winter. The 

 object of the scheme is to bring scientific knowledge, in a 

 popular form, before societies which are unable to pay large 

 fees to professional lecturers, the work of lecturing and 

 demonstrating being gratuitous on the part of the members. 



The Department of the Interior of Canada has recently 

 issued a " Dictionary of Altitudes in the Dominion of 

 Canada," by James White, the work being a supplement 

 to that author's "Altitudes in Canada." The arrange- 

 ment is alphabetical, by provinces and territories, and the 

 vjfijme should be of service to engineers, surveyors, and 

 others who wish to know the altitude of any place in the 

 dominion. 



Vol. i. of the second series of the Proceedings of the 

 London Mathematical Societv. which has just been pub- 

 lished by Mr. F. Hodgson, of Farringdon Street, contains 

 obituary notices of Profs. L. Cremona, G. Salmon, 

 J. Willard Gibbs, and Mr. G. H. Stuart, in addition to the 

 papers read before the society from January, 1903, to 

 February, 1904. 



The volume for 1903 of the Journal and Proceedings 

 of the Royal Society of New South Wales has just reached 

 us. It is issued in this country by George Robertson and 

 Co., of 17 Warwick Square, E.C. 



We have received a copy of a catalogue (published by 

 R. e Brothers, Melbourne) of the fine collection of eggs and 

 nests of Australian birds in the possession of Mr. D. 

 le Souef, director of the Melbourne Zoological Gardens. 

 NO. 1816, VOL. 70] 



OUR ASTRONOMICAL COLUMN. 



The Return of Tempel's 'Second (1873) Comet. — The 

 comet Tempel, (1873), which has a period of about 528 

 years, made its last perihelion passage on July 28, 1899, 

 and should, therefore, reappear during the later months of 

 the present year. Although this object will be but of feeble 

 intensity throughout the apparition, it should certainly be 

 observable, therefore M. J. Coniel, of the Paris Bureau 

 des Longitudes, has calculated a daily ephemeris for it 

 from the following elements, which were computed by 

 Mr. Schulof. This ephemeris, an extract from which is 

 given below, covers the period July 29 — October 25, and 

 is published in No. 3962 of the Astronomische Nach- 

 richten. 



Epoch 1904 October 30-0 M.T. Paris. 



M =357 5' 49 

 00=185 44 39] 

 a =120 59 52 -1904-0 

 / = 12 3$ 55 I 

 ip = 32 50 37 

 M =672"-i75 

 log a =0-41868 



In computing these elements the perturbations of Jupiter 

 and Saturn have been taken into account. 



Ephemeris T2h. (M.T. Paris), 

 a (npp.) i (app.) 



Aug. 17 



-4 9 10 ... 0-2242 



-5 17 34 ... 0-226S 



- 6 26 33 ... 0-2292 



-7 35 56 ■■■ o23'5 



-8 45 31 o'2336 



-9 55 4 ■■ o'2356 



14 23 45 

 „ 21 ... 14 31 13 

 „ 25 ... 14 39 4 

 ,, 29 ... 14 47 17 



Sept. 2 ... 14 55 53 

 ,, 6 ... 15 4 51 



Spectr.'V of Neptune and Uranus. — The results of a 

 photographic study of the spectra of Neptune and Uranus 

 are given in No. 13 of the Lowell Observatory Bulletins 

 by Mr. V. M. Slipher, reproductions of the photographs 

 being given on an accompanying plate. 



The spectrogram of Neptune extends from K 4300 to D, 

 and is compared with that of the solar type star 3 

 Geminorum. There is an apparent brightening, in the 

 planetary spectrum, on the more refrangible side of h 

 which seems to indicate intrinsic emission, but may be due 

 to the contrast afforded by two strong absorption bands. 

 H/S is stronger in the Neptunian spectrum, and one photo- 

 graph shows H7 stronger, thereby indicating the presence 

 of free hydrogen in the planet's atmosphere. 



The spectrum of Uranus from F to A. 350 exhibits no 

 departure from the normal solar spectrum, but on one 

 photograph there is apparently a line in the position of D,, 

 indicating, if real, the presence of helium. 



A comparison of the two spectra shows that although 

 free hydrogen is present, in the atmosphere of Uranus it 

 is not so abundant as in that of the outer planet. Three 

 bands situated at \ 510, \ 543, and \ 577, respectively, are 

 also stronger in the spectrum of the latter, thereby indicat- 

 ing that the atmosphere of Neptune is much more exten- 

 sive than that of Uranus. The origins of these bands are 

 at present unknown, unless the second and third are due 

 to water-vapour, and Mr. Slipher suggests that they may be 

 due to gases lighter than, but similar to, hydrogen and 

 helium, which have not been recorded in stellar spectra 

 because the temperature conditions in stars are, probably, 

 unfavourably high. 



The Varl\ble Radtal Velocity of 5 Orionis. — In a 

 recent paper. Prof. Hartmann pointed out that the value 

 which he obtained for the period of the " oscillations " of 

 5 Orionis did not agree with those previously published by 

 M. Deslandres. 



The latter observer now shows, in No. 3963 of the 

 Astronomische Nachrichten, that although the results are 

 divergent the observations are confirmatory, for his result 

 was based on very few observations, and is exactly one- 

 third of the value obtained by Prof. Hartmann, the numbers 

 being 1-92 and 5-73 (days) respectively. Prof. Pickering 

 pointed out some time ago that periods of variable radiat 

 velocity which are derived from few observations are 



