88 



NA TURE 



[May 24, 1906 



motion hitherto unsuspected, and he has obtained a value 

 for the motion which he believes to be more correct than 

 could be determined by ordinary micrometric measures. 

 In this case a period of fourteen years separated the times 

 of taking the photographs {Compies rcndus. No. 19, 1906). 



.Me.isures of Double and Multiple Stars.— The 

 measures of 1066 double and multiple stars are published 

 in vol. ii., part iii. (astronomical series), of the Publica- 

 tions of the University of Pennsylvania by Prof. Doolittle. 



The measures were made with a ' wire micrometer 

 attached to the 18-inch refractor of the Flower Observ- 

 atory, arid include, among others, 7^3 Burnham stars, 

 109 02, and 102 2 stars. Four hundred and ninety-two 

 stars from Prof. Hough's catalogue have also been re- 

 measured but are not included; it is Prof. Doolittle's inten- 

 tion to re-measure all the stars discovered by this observer. 



The micrometer, the corrections of the instrument, and 

 the method of observing are all fully discussed in the 

 present publication, which is a continuation of part iii., 

 vol. i. 



Part ii., vol. ii., of the same publications gives the 

 results of the observations made with the zenith'telescope 

 of the Flower Observatory from October i, 1901, to 

 December 28, 1903, and also contains a re-discussion of 

 the 1896-1898 series, of which the details appeared in 

 part ii., vol. i., in 1899. 



Oeservatio.vs of Comet igosc— Numerous observations 

 of comet 1905c are recorded in No. 4090 of the Astrono- 

 mische Nachrichten. 



This object was observed at Vienna from December 17, 

 IQ05, to January 14, iqo6, and during that time its apparent 

 diameter increased from 2' to 4'-5', the length of its 

 tail from 5' to 40', and its total magnitude from*9.5 to 4.0. 

 On December 30 a nucleus of magnitude 6-0 was observed. 



Hehometer observations at the Cape Observatory showed 

 the comet as a faint nebulous mass with no visible' nucleus. 

 Observations of position were recorded from February ? 

 to February 20, 1906. 



The observations at Strassburg Observatorv extended 

 over the period December 10 to March 21, and the apparent 

 position, the total magnitude, and the diameter were re- 

 corded on eleven different dates. 



A Lunar Tide on Lake Huron.— Whilst examining the 

 curves showing the periodical oscillations of the seiches 

 on Lake Huron, Prof. W. J. Loudon, of Toronto Uni- 

 versity, was struck by the regularity of their general out- 

 line, which seemed more marked in calm w^eather. Further 

 investigation of the matter showed a well-marked and 

 regular rise and fall twice a dav, and also show^ed that 

 no oscillation of the lake could have a period of more than 

 four hours. 



From these facts Prof. Loudon concluded that a true 

 lunar tide occurs on Lake Huron, a conclusion which his 

 further experiments seemed to verify. 



THE HAUNTS OF THE OKAPI. 

 ^CCORDING to a report in Monday's Times (May 21) 

 the expedition to the Congo Free State under the 

 charge of Captains Boyd Alexander and C. B. Gosling has 

 been successful, not onlv in procuring a fine skin (and it 

 may be hoped a skeleton) of the okapi, but likewise in 

 obtaining some important particulars with regard to the 

 habits of this animal. The specimen, which 'it is stated 

 will ultimately find a home in the Natural History Branch 

 nf^ the British Museum, was obtained at Bima, on the River 

 \\'plle, in the northern territory of the Congo State. It 

 is mentioned in the letter that 'the animal was seen alive 

 hy the expedition, but further particulars on this point are 

 desirable, as it is not stated whether anvone but the 

 Portuguese collector by whom it was trapped had this 

 good fortune. The animal was caught in a pit according 

 to native fashion, previous attempts to shoot it having 

 proved ineffectual. 



Hitherto the only definite account of the kind of country 

 inhabited by the okapi and the probable nature of its food 

 is one given by Mr. J. David under the title of " Weitere 

 Mitteilungen iiber das Okapi," and published in vol. Ixxxvi. 

 of Globus (1904). Captain .Alexander's notes, which differ 



NO. 1908, VOL. 74I 



in some respects from the former, are theirefore of great 

 value and interest, and may be quoted in full. 



" The okapi here is generally found singly or in pairs, 

 but Mobatti hunters state that sometimes three may be 

 found together. An essential to the life of the okapi is a 

 small stream of water with some muddy and swampy 

 ground on cither side. In this grows a certain large leaf 

 that on its single stalk attains a height of 10 feel. It is 

 the young leaf of this plant that is the favourite food of 

 the okapi, and I venture to say that where the plant is 

 not to be found the animal will not e.xist. During the 

 night he will wander along in the mud and water in search 

 of it. Here he may be found feeding as late as 8 a.m. in 

 the morning, after which he retires to the seclusion of the 

 forest, where he remains until nearly dusk. On the three 

 occasions that I was at close quarters with the beast, he 

 was perfectly concealed in this swamp leaf. Near the River 

 Welle I found his spoor on ground frequented by buffalo 

 and Vi'aterbuck, but this is unusual, and his companions 

 in the forest are the elephant, the greater bushbuck, the 

 yellow-backed and small red duikers. The okapi is very 

 quick of hearing, and in that respect is classed by the 

 Mobatti with the bushbuck (local name ' bungana '). In 

 the forest here I consider this latter beast to be more 

 diflficult to obtain than the former. On the hunting ground 

 of the first village that 1 visited I estimated the number of 

 okapi as five or six, at the second and third nil ; and 

 twenty miles south in the forest, on very likely ground 

 where my guide said they were formerly numerous, there 

 was one only, probably owing to rubber-collectors who had 

 been there." 



Several specimens had been speared, shot, or trapped by 

 natives shortly before the date of Captain Alexander's 

 visit, but time did not admit of further investigation. The 

 sex of the new specimen is not stated, but it is to be hoped 

 that it will prove to be a male, as Sir Harry Johnston's 

 example, now exhibited in the Natural History Museum, is 

 a female. A pair of okapis are exhibited in the Congo 

 Free State Museum at Tervueren, near Brussels, which 

 also possesses other skins ; and there are likewise a few 

 other examples in Europe, notably one in Italy and another 

 in Mr. Rothschild's museum at Tring. It is a great 

 pity that the Belgian Government does not take immediate 

 steps to publish coloured figures of its specimens in 

 order to aid in solving the question as to whether there 

 is more than one species (or race) of okapi. Important 

 information on this point will, however, doubtless be 

 afforded by the .Alexander-Gosling specimen, which, it may 

 be hoped, will also indicate (if a male) whether the tips of 

 the horns always protrude through the skin, and thus fore- 

 shadow the antlers of deer. 



THE TARAr/ERA VOLCANIC RIFT. NEW 

 ZEALAND. 

 A/r R. J.AMES .MACKINTOSH BELL, director of the 

 New Zealand Geological Survey, contributes a paper 

 to the April number of the Geographical Journal describing 

 the present topography of the great volcanic rift of 

 Tarawera, in the north island of New Zealand, and the 

 changes which have taken place in the configuration of the 

 region since the great eruption of Mount Tarawera on 

 June 10, 1SS6. which is memorable for the destruction of 

 the famous pink and white terraces, and th^ir submergence 

 in Lake Rotomahana. 



Mount Tarawera lies near the centre of the Taupo 

 volcanic zone, and about 135 miles south-east of .Auckland. 

 This zone, which has a breadth of some twenty-five miles, 

 extends from near the great volcanic cones of Ruapehu, 

 Tongariro, and Ngaurahoe north-eastwards to White 

 Island, on the Bay of Plenty, a distance of nearly 160 miles. 

 A great rift, which was the scene of greatest intensity of 

 the 1886 eruption, stretches from near Lake Okaro along 

 the Tarawera range to Mount Wahanga, in the most north- 

 easterly part. This rift, really a line of craters, forms a 

 huge fissure about nine miles in length, cutting the summit 

 of the range, and appearing on its south-western slope. 

 It is divided into several somewhat distinct craters by low 

 partitions, and on the south-west side a long narrow rift 

 extends to the base of the hill, so far as the edge of Lake 



