72 



NA TURE 



{May 15, 1884 



galena, fahlertz, and sulphurets of silver and gold. Some of the 

 mines produce beautiful filaments of native silver, and one of 

 the specimens showed a very unusual association, viz. fine fila- 

 ments of silver on gray copper. — The Secretary (Robert Gray, 

 V. P.R.S.E. ) exhibited a specimen of the Calandra lark [Alauda 

 calandra] from the neighbourhood of Madrid, showing a pecu- 

 liar malformation of both mandibles, which seemed to render it 

 impossible for the bird to pick up its food. The specimen had 

 been sent to him by Dr. A. C. Stark, and is to lie deposited 

 in the Edinburgh Museum of Science and Art. — Mr. Gray also 

 reported the occurrence of at least three instances of the stock 

 dove (Columba trnas) in Roxburghshire, and made some remarks 

 on the distribution of the species in the border counties. This 

 bird has now been found to be a regular visitant to the counties 

 "I Berwick, Dumfries, and Roxburgh, in all of which it 

 breeds. — Mr. Harvie-Brown. F.R.S.E., F.Z.S., exhibited, with 

 remarks, a specimen of the black redstart (Kuticilla titys, Scop.), 

 taken last month on the Pentland Skerries, Pentland Firth. The 

 specimen was a male adult, and is said to be the fifth of the 

 species recorded in Scotland. 



Mathematical Society, May 9. — Dr. Thomas Muir, 

 F.R.S.E., president, in the chair. — Prof. Crum Brown delivered 

 an address, interesting alike to mathematicians and to chemists, 

 on the hypothesis of Le Bel and Van't Hoff. — Dr. Muir gave a 

 preliminary account of a treatise on Determinants, published in 

 1825, and unknown to all writers on the history of the subject. 



Dublin 



Royal Society, April 21. — Section of Physical and Experi- 

 mental Science. — Arthur Hill Curtis, I.L.D., in the chair. — 

 Notes from the Physical Laboratory of the Royal College of 

 Science, by Prof. W. F. Barrett. — On the local heliostat, by G. 

 Johnstone Stoney, D.Sc, F.R.S. This instrument was designed 

 by the author many years ago, and made for him most satisfac- 

 torily by Messrs. Spencer and Sons, opticians, of Dublin, who 

 have since constructed several reproductions of it for physicists 

 at home and abroad, at the suggestion of one of whom it is now 

 described. The instrument is in some degree a modification of 

 Gambey's heliostat, but it differs from that apparatus by being 

 simpler in its details, steadier, easier to use, and cheaper. These 

 advantages are gained by sacrificing the generality of Gambey's 

 instrument and providing only for stations within a limited range 

 of latitude, usually about 10°, which, for 'example, enables one 

 instrument to be used anywhere within the British Islands. 

 Hence it has been called the local heliostat. The adjustment 

 for latitude is of the simplest kind. After it is made, the instru- 

 ment is to be levelled, and an arrangement based on the prin- 

 ciple of the sun-dial enables it in about half a minute to be 

 placed in the meridian. A polar axis is driven by a common 

 clock at the rate of one revolution in twenty-four hours. To the 

 upper end of this axis an arm is jointed, which, by a simple 

 contrivance, can be pointed towards the sun, and which the 

 clockwork, while in action, will then cause to follow that lumin- 

 ary. This arm trammels the mirror in the same way as in 

 Gambey's instrument ; and the reflected ray continues in the 

 direction of a bar which can be placed in any azimuth and can 

 be inclined up or down within reasonable limits. The direction 

 of this bar, and with it of the reflected ray, can be readjusted, 

 if necessary, in one or two seconds without disturbing the rest 

 of the apparatus. The local heliostat has hitherto been made 

 with mirrors about six inches by three for use in physical labora- 

 tories, but the design has been rendered so simple that it could 

 be made at small cost with a mirror as large as a toilet glass, and 

 driven by a cheap common clock. This would furnish an in- 

 strument which might be employed in physiological experiments 

 on plants, in photography, and for any other purposes in which 

 a large sunbeam in a fixed direction would be useful. — Dr. C. E. 

 Fitzgerald exhibited Mr. P. Smith's model illustrating the 

 conjugate movement of the eyes. 



Section of Natural Science.— V. Ball, M.A., F.R.S. , in the 

 chair. — The following papers by D. Sharp, M.B., were com- 

 municated by Prof. W. R. McNab, M.D. : — (1) Descriptions of 

 new genera and species of Hawaiian Coleoptera ; (2) Catalogue 

 of Hawaiian Coleoptera, with localities, distribution, and habits : 

 (3) Topographical table of Hawaiian Coleoptera, with summaries, 

 generalisations, and comments. — Prof. A. C. Haddon, B.A., 

 F.Z.S., on the generative and urinary ducts in Chitons. The 

 author discussed the various views as to the nature of the urinary 

 ducts in Chitons. His own investigations supported Sedgwick's 

 account as opposed to Hallcr's, and an oviduct was proved to 



exist in CIi. (Trachydermon) ruber, Linn. — Notes on some of the 

 Irish crystalline iron ores, by G. II. Kinahan. M.R.I.A. — Addi- 

 tional notes on the phenomena attending the eruption of Krakatoa, 

 by J. Joly, B.E. These included an account, received from Capt. 

 Thomson of the Medea, relating to phenomena observed on 

 August 22 to 24, while the Medea was in the Sunda Straits. 

 I In ^l embraced electrical effects, showers of sand and gravel, &c. 

 At 2 p.m. on the 26th Capt. Thomson heard the first explosion ; 

 others succeeded every ten minutes. This geyser-like regularity 

 was substantiated by all accounts received by the author. A 

 column of dust arose to the westward immediately after the first" 

 explosion, Two observations enabled the height of this column 

 to be computed. One gave seventeen, another twenty-one miles. 

 The last included some doubtful factors, the observation being 

 made three hours after first explosion. Further examination of 

 the dust and pumice revealed hematite in thin blood-red flakes. 

 The feldspars seemed divisible into two groups depending on 

 optical and structural differences. Pyrites occurred not alone as 

 an inclusion in the feldspars but also in the hypersthene. Optical 

 tests rendered highly probable the presence of a triclinic 

 pyroxene. 



Manchester 



Literary and Philosophical Society, March 4, — H. E. 

 Roscoe, F.R.S., president, in the chair. — A paper was read on 

 the production and purification of gaseous fuel for industrial 

 purposes, with the results of several large applications of a 

 system, by W. S. Sutherland. 



March iS. — H. E. Roscoe. F.R.S., president, in the chair. — 

 Notes on the meteorology and hydrology of the Suez Canal, by 

 Dr. W. G. Black, F.R.Met.S. 



Vienna 



Imperial Academy of Sciences, April 24. — F. von'Hoch- 

 stetter, fifth communication to the seventh report of the Prehis- 

 Commission ; on the tumuli at Froeg, near Rosegg 

 (Carinthia). — K. Zulkorosky, on the aromatic acids as dye- 

 forming matters. — W. Stephanie, on rotation of the moon. — T. 

 Unterweger, on the aurora borealis. — T. Habermann and M. 

 Hcenig, on the action of cuprum hydroxide on some sugars. — 

 F. Berger, on the preparation of phenylcyanide. — E. Spiegler, 

 contribution to a knowdedge of the euxanthone group. —Contri- 

 bution to a knowledge of diphenylglucetoxin, by the same. — 

 T. von Hepperger, on the position and figure of isochrones' in 

 comets' tails. 



CONTENTS page 



Daniell's " Physics " 49 



Recent Chemistry 51 



Letters to the Editor: — 



Reply to Mr. Grubb's Criticisms on the Equatorial 



Coude of the Paris Observatory. — M. Lcewy . . 52 

 Dust-Free Spaces. — Edw. W. Serrell, Jun. ; Prof. 



O. J. Lodge $3 



The Supposed Volcanic Dust Phenomena. — Thos. 



Wm. Backhouse 54 



Pons' Comet. — A. S. Atkinson 55 



Snow and Ice Flora. — Prof. Julius von Haast . . 55 



The Rotation Period of Mars. — W. F. Denning . . 55 

 " The Electrical Resistance of the Human Body." — Dr. 



W. H. Stone ; Prof. A. E. Dolbear 56 



Instinct in Birds. — Wm. Brown 56 



Walls's " Inorganic Chemistry." — Dr. H. Watts . . 57 

 The Recent Earthquake.— C. L. Prince ; C. E. De 



Ranee 57 



Notes on Earthworms. By Prof. T. McKenny 



Hughes, F.R.S 57 



The Low Barometer of January 26. 1884 58 



The Theory of Sunspots. By Rev. T. W. Webb . 59 



The Earthquake. By W. Topley ( With Map) . ... 60 

 Volcanoes on the Shores of Lake Nyassa, Africa. 



By Dr. H. J. Johnston-Lavis 62 



Notes 63 



Our Astronomical Column : — 



The Approaching Return of Olbers' Comet 64 



The Building of the Alps, II. By Prof. T. G. Bonney, 



F.R.S., Pres.G.S ' 65 



Recent Morphological Speculations, 1 67 



The Paris Academy of Sciences 69 



Societies and Academies 70 



