322 



NATURE 



{July 1 8, 1878 



length about 5,210, in the same position as one of the most con- 

 spicuous of the dark lines we had observed to be produced by 

 vapour of magnesium with hydrogen in our iron tubes. This 

 line is best seen, i.e., is most steady, when no Leyden jar is used, 

 and the rheotome (the coil we used has an ordinary self-acting 

 one) is screwed back, so that it will but just work. It may, 

 however, be seen when the coil is in its ordinary state, and when 

 a small Leyden jar is interposed ; but it disappears (except in 

 flashes) when a larger Leyden jar is used, if the hydrogen be at 

 the atmospheric pressure. This line does not usually extend 

 across the whole interval between the electrodes, and is some- 

 times only seen near the negative electrode. Its presence seems 

 to depend on the temperature, as it is not seen continuously 

 when a large Leyden jar is employed, until the pressure 

 of the hydrogen and its resistance is very much reduced. 

 When well-dried nitrogen or carbonic oxide is substituted 

 for hydrogen, this line disappears entirely ; but if any hydro- 

 gen or traces of moisture be present it comes out when the 

 pressure is much reduced. In such cases the hydrogen lines 

 C and F are always visible as well. Sometimes several fine 

 lines appear on the more refrangible side of this line, between it 

 and the b group, which give it the appearance of being a narrow 

 band, shaded on that side. We have used various samples of 

 magnesium as electrodes, and they all give the same results. 

 We have also used hydrogen, prepared and purified in different 

 ways : hydrogen prepared by the action of zinc on dilute 

 sulphuric acid, purified by an acid solution of bichromate or 

 permanganate, and by potash, and dried by sulphuric acid ; 

 electrolytic hydrogen ; hydrogen from dry formiate of soda and 

 soda lime ; hydrogen occluded by sodium and expelled by heat ; 

 and hydrogen occluded by palladium and expelled by heat. In 

 the last two cases the whole apparatus was connected by fusion, 

 and a Sprengel pump, also connected by fusion, employed to 

 remove the air. In all cases the phenomena were the sa me. 



In addition to the above-mentioned line, we observed that 

 there is also produced a series of fine lines, commencing close to 

 the most refrangible line of the b group, and extending with 

 gradually diminishing intensity towards the blue. These lines are 

 so fine and close to one another, that in a small spectroscope they 

 appear like a broad shaded band. We have little doubt that the 

 dark absorption line, with wave-length about <),\^o, shading 

 towards the blue, which we previously observed in our iron 

 tubes, and described in our last communication, was a reversal of 

 part of these lines, though the latter extend much fitrther towards 

 the blue than we had observed the absorption to extend. In 

 fact, the bright lines extend somewhat more than half the 

 distance between b and F, from forty-five to fifty being visible, 

 and placed at nearly equal distances from each other. They also 

 commence close to the b group, i.e., with a wave-length nearly 

 5,164, but the first two or three lines at that end are not so 

 bright as those which immediately succeed them. The light 

 giving these lines does not extend to more than a short distance 

 from the electrodes, and is generally most conspicuous at the 

 negative electrode. There is a difficulty in consequence of the 

 flickering character of the discharge in getting any accurate 

 measures of them, though they are bright enough, especially at 

 the less refrangible end, to be easily seen. The comparative 

 faintness of the light from the iron tubes appears to us almost 

 sufficient to account for our not having seen the reversed lines so 

 completely as the bright ones ; nevertheless, it is quite in accord- 

 ance with what we in other cases observed, to suppose that some 

 of these lines may be more easily reversed at the temperature of 

 the iron tubes than others. 



Zoological Society, June 18. — Arthur Grote, vice-presi- 

 dent, in the chair. — The Secretary read extracts from a letter 

 addressed to him by Mr. E. L. Layard, containing remarks on 

 two species of New Caledonian birds. — A second communica- 

 tion from Mr, Layard stated that there was an example of the 

 recently -described woolly cheetah {Felis laned) in the South 

 African Museum at Cape Town. — Mr. Edward R. Alston read 

 a paper on the squirrels of the Neotropical region, in which he 

 recognised twelve out of fifty-nine described species, and re- 

 described two, Sciurus rufo-niger, Pucheran, and S. pusillus, 

 Geoffroy, which had been recently overlooked. — Mr. Sclater 

 exhibited and made remarks on a third collection of birds from 

 Duke of York Island, New Britain, and New Ireland, which 

 he had received from the Rev. George Brown, C.M.Z.S. 

 Amongst them was an example of a new fruit-pigeon, proposed 

 to be called Carpophaga melanochroa. — A communication was 

 read from Dr. M. Watson, containing a description of the male 



generative organs of Chlamydophorus truticalus and Dasvpus 

 sexcinctus.^—A communication was read from Prof. Garrod on 

 certain points in the anatomy of Levaillant's darter (Ploftis 

 levaillanti). — A communication was read from Messrs. Garrod 

 and Turner on the gravid uterus and placenta of Hyomoschus 

 aqtmticus. — A communication was read from Mr. F. Moore 

 containing the descriptions of New Asiatic butterflies of the 

 family Hesperiidas. — A second communication from Mr. Moore 

 gave a list of the lepidopterous insects collected by the late Mr. R. 

 Swinhoe, in the Island of Hainan. — A communication was read 

 from the Marquis of Tweeddale, F.R.S., being the tenth of his 

 contributions to the ornithology of the Philippines. The pre- 

 sent paper gave an account of the collection made by Mr. 

 A. H. Everett in the Island of Bohol. The collection con- 

 tained representatives of forty-seven species. Although all of 

 these were previously known, seven of them had not been before 

 recorded as being inhabitants of the Philippines. — Dr. O. 

 Finsch, C.M.Z.S., read the description of a new species of 

 starling from Lake Marka-kul, in the Chinese High Altai, 

 which he proposed to name Sturnus poltaratzskyi, after Gen. 

 Poltaratzsky, Governor of Semipalatinsk. — A communication 

 was read from Mr. H. W. Bates containing the description of 

 new species of coleopterous insects ( Gcodephaga and Longicornia) 

 taken by the late Dr. Stoliczka during the Forsyth Expedition 

 to Kashgar in 1873-1874. — A communication was read from 

 Dr. G. Hartlaub, in which he gave the description of a new 

 species of Notauges {N. hildebrandti) of Cabanis, M., discovered 

 by Mr. Hildebrandt at Ikanga in Ukamba, Eastern Africa. — 

 A communication was read from Lieut. -Col. R. H. Beddome, 

 C.M.Z.S., giving the description of a new batrachian from 

 Southern India belonging to the family Phryniscidce, which he 

 proposed to call Melanobatrachus indiais. — SirV. Brooke, Bart., 

 exhibited and made remarks on a fine head of the male Gazella 

 granti, originally described from sketches made by Capt. Speke 

 during Speke and Grant's expedition. The present specimen 

 had been shot by Mr. Arkwright about eighty miles from Ugogo 

 in Eastern Africa. — A communication was read from Prof. 

 V. V. Barboza du Bocage, F.M.Z.S., containing a list of the 

 antelopes observed in Angola. — A communication was read 

 from Mr. Carl Bock, in which he gave the description of two 

 new species of shells from China and Japan. — A communica- 

 tion was read from Mr. Edgar A. Smith, containing the de- 

 scription of five new shells from the Island of Formosa and 

 the Persian Gulf, with notes upon some known species. — 

 Messrs. Godman and Salvin read the descriptions of .some ap- 

 parently new species of butterflies from New Ireland and New 

 Britain, received from the Rev. G. Brown. — Mr. O. Salvin 

 read the twelfth of a series of reports on the collection of birds 

 made during the voyage of H.M.S. Challenger. The present 

 paper contained an account of the Proceilariida?, collected 

 during the expedition. Eighty specimens had been obtained 

 belonging to twenty-two species. — Mr. Sclater read some sup- 

 plementary notes on the curassows now or lately living in the 

 Society's gardens. — Mr. J. Wood-Mason read. a paper on the 

 structure and development of the trachea in the Indian painted 

 snipe {Rhynclicra bengalensis). 



Physical Society, June 22. — Prof. G. C. Foster, vice-presi- 

 dent, and afterwards Prof. W. G. Adams, president, in the 

 chair. — The following candidate was elected a Member of the 

 Society : Mr. F. W. Grierson. — Prof. W. G, Adams exhibited 

 a new form of polariscope suitable for projecting on to a screen 

 the figures formed by any crystal, and for measuring the angle 

 between the optic axes. Parallel light from the electric lamp, 

 after traversing a Nicol of about two-inch aperture, is rendered 

 divergent by a set of lenses. The crystal under examination is 

 placed in a recess formed by removing a slice from the middle 

 of a spherical lens which is capable of motion in any direction 

 about its centre, while any movement in the vertical plane pass- 

 ing through the axis of the instrument can be measured by a 

 scale and Vernier ; and if, by such a motion, the point on the 

 screen representing the position of one axis, when the two are 

 in the vertical plane, be transferred to that indicating the posi- 

 tion initially occupied by the other axis, we have at once a 

 measure of the optic angle of the crystal, for the rotation of 

 two piano-spherical lenses forming an exact sphere has no effect 

 on the direction of the beam. — Mr. Walter Baily read a paper 

 on the effect of starch, salicene, unannealed glas=-, &c., on 

 polarised light. In his experiments light was passed through a 

 Nicol's prism, then through a quarter undulation plate, and then 

 through a body having an optical structure 5.ymmetrical round 



