478 



NATURE 



[September i 7, 



Ontario, by G. C. Hoffmann ; sun-spots observed at McGiU 

 Observatory, by C. H. McLeod ; a test of Ewing and Mac- 

 Gregor's method of measuring the electric resistance of electro- 

 lytes, by J. G. McGregor ; the later physiographical geology of 

 the Rocky Mountain region in Canada, by G. M. Dawson ; 

 fossil plants from the Similkameen Valley and other places in 

 the southern interior of British Columbia, by Sir J. W. Dawson. 



Messrs. Swan Sonnenschein and Co. will issue the fol- 

 lowing books during the autumn season: — "The Colours of 

 Animals," by Prof. Beddard, with coloured and other plates 

 and woodcuts ; "Text-book of Embryology: Man and Mam- 

 mals," by Dr, Oscar Hertwig, Professor of Comparative 

 Anatomy in the University of Berlin, translated and edited 

 from the third German edition (with the assistance of the 

 author) by Dri E. L. Mark, Professor of Anatomy in Har- 

 vard University, with 389 illustrations and 2 coloured 

 plates; "Text-book of Embryology : Invertebrates," by Drs. 

 Korschelt and Heider, of the University of Berlin, translated 

 and edited by Dr. E. L. Mark, with several hundred illustra- 

 tions ; " Text-book of Animal Palaeontology," by Dr. Thomas 

 Roberts, designed as a supplement to Claus and Sedgwick's 

 "Text book of Zoology," illustrated ; " Text-book of Geology," 

 adapted from the work of Dr. Emanuel Kayser, Professor in 

 the Univer.-ity of Marburg, by Philip Lake, of St. John's Col- 

 lege, Cambridge, with illustrations; "Text-book of Zoology," 

 by Dr, C. Claus, of the University of Vienna, and Adam Sedg- 

 wick, F.R.S., Vol. II. "Mollusca to Man," third edition; 

 "The Geographical Distribution of Disease in England and 

 Wales," by Alfred Haviland, M.D., with several coloured 

 maps; "Introductory Science Text-books" — Additions: In- 

 troductions to the study of " Physiography," by H. M. Hutchin- 

 son ; "Zoology," by B. Lindsay; "Amphioxus," by Dr. B. 

 Hatschek, of the University of Vienna, and James Tuckey ; 

 "Geology," by Dr. Edward Aveling ; "Physiological Psycho- 

 logy," by Dr. Th. Ziehen, of the University of Jena, adapted by 

 Dr. Otto Beyer, with 21 figures. "Young Collector Series" — 

 Additions: "The Telescope," by J. VV. Williams; "British 

 Birds," by the Rev. H. C. Macpherson : "Flowering Plants," 

 by James Britten; "Grasses," by W. Hutchinson; "Fishes," 

 by the Rev. H. C. Macpherson; "Mammalia," by the Rev. 

 H. C. Macpherson. 



An instrument for optical comparison of transparent liquids, 

 named a liquoscope, has been recently devised by M. Sonden, of 

 Stockholm. Two hollow prisms holding the liquids are sepa- 

 rated by a partition at right angles to the refracting angle. 

 The whole is placed in a vessel filled with glycerine, and which 

 allows of vision in a horizontal direction through plane glass 

 plates. The deflection of the light rays through the prisms is 

 thus compensated. So long as the two liquids have the same 

 optical action, one sees a distant mark (say a black paper strip 

 on a window) as a straight connected line ; but its halves are 

 relatively displaced if the liquids have different refractive power. 

 The amount of displacement gives a measure of the difference, 

 the positive or negative nature of which also appears from the 

 direction of displacement. The author recommends his appa- 

 ratus for chemical purposes, especially comparison and testing of 

 fats and oils, analysis of glycerine, &c., and detection of mar- 

 garine in butter, margarine greatly lowering the index of 

 refraction. 



Herr Hufner has lately pointed out some of the biological 

 bearings of the fact (observed in experiment along with Herr 

 Albrecht) that long light-waves are much more strongly absorbed 

 by water than short ones. If the lover marine animals had, 

 like man, the liveliest light perception with yelbw rays, and a 

 certain intensity of light ware necessary to them, they must live 

 at a less depth than if their visual organs were most strongly 

 NO. I I 42, VOL. 44] 



affected by short- waved rays. Thus, e.g.^ if they needed as 

 much yellow light as that of the full moon, they could not live 

 deeper than 177 metres (say, 593 feet). Yet they are found at 

 all depths where food, oxygen, and a suitable temperature exist. 

 On the other hand, the existence of plants having chlorophyll 

 depends on light, and we might expect that the distribution of 

 non-parasitic plants would be very limited; which is the case, 

 no plant organisms being found under 200 fathoms. Green 

 plants assimilate best in yellow light; ani supposing plants to 

 assimilate in moonlight they would find their limit at the ab )ve 

 depth (177 metres). But while yellow is here weakened to 

 0-00000I6 of its brightness, indigo blue has still 0-007829 of its 

 original strength, and the assimilation with blue rays will be 

 660 times as strong as with yellow. Different coloured marine 

 plants react differently according to the colour of light, and 

 they have accordingly different distribution in depth. 



The additions to the Zoological Society's Gardens during the 

 past week include two Pinche Monkeys {Midas cedipus S ? ) 

 from Granada, presented by Mr, A. Aitken ; a Fallow Deer 

 [Dama vulgaris $ ), British, presented by Mr. J. Johnston ; a 

 Persian Gazelle ( Gazella subgutttirosa ? ) from Persia, presented 

 by Baron Ferdinand de Rothschild ; a Common Cormorant 

 {Phalacrocorax carbo), British, two Yellow-browed Buntings 

 {Emberiza chrysophrys), two Red-backed Buntings {Emberiza 

 rutila), a Bunting {Ejiiberiza cioides), two Japanese Green- 

 finches {Fringilla kawarahibi, var.) from Japan, purchased; 

 a Yellow-footed Rock Kangaroo {Pelrogale xanthopus ? ), born 

 in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



The Linear Arrangement of Stars.— x\lthough the 

 arrangement of stars in curves has often been noted and studied, 

 little attention has been paid to what is apparently a more 

 striking and prevalent feature, viz. straight lines and pai-allel 

 arrangement of pairs, lines, and bands of stars, and of irresolv- 

 able wisps. Our knowledge of the structure of the sidereal 

 universe is therefore extended in the required direction by some 

 results obtained by Mr. T. W. Backhouse from observations 

 which he has made during the last nine years in Sunder- 

 land. The area of the sky selected for scrutiny is that portion 

 of the Milky Way included between 15, 13, 8 Monocerotis, 

 a Orionis, C Tauri, and 5, fx, | Geminorum ; and the configura- 

 tions in this portion have been examined chiefly with a binocular 

 field-glass of 2 05 inches aperture. The observations have been 

 divided into sections, referring respectively to lines and parallel 

 arrangements of stars, to those in clusters, to nebulous wisps, to 

 nebulee, and to miscellaneous lines. In these are given the 

 detailed structure in different parts of the area showing various 

 systems of parallel lines and wisps, together with their position- 

 angles referred to that portion of Gould's galactic equator which 

 runs through the middle of the area in question. The parallel 

 arrangement of the stars, and an arrangement in straight lines, 

 is strikingly obvious from the maps which illustrate the tabulated 

 results of the observations. Besides the maps, sixteen figures 

 have been drawn to show the various angles of position of the 

 lines and streams with reference to the central line or axis of the 

 Milky Way. From these figures it is apparent that the angles 

 of position are grouped more numerously in certain directions 

 than in others, the principal directions being nearly parallel to 

 the galactic equator. Also, there is a great deficiency of position- 

 angles at right angles to this equator. A wonderful case of 

 radiation of stars and wisps in a fan-shaped group has been 

 found, 68 Orionis being approximately the centre. One con 

 elusion derived from the investigation is, that the stars and wisps 

 in parallel lines are probably in the same region of space ; and 

 therefore that the majority of the stars in extensive tracts of the 

 area examined are really near one another. 



Wolf's Periodic Comet. — This object can now be fairly 

 seen by means of a small telescope. It will pass through the 

 Hyades about September 25, and be 3° south of Aldebaran on 

 October 2. The following ephemeris, from one given by Herr 



