June 15, 1893J 



NATURE 



'59 



the earth, and in the actual observation here mentioned the 

 distance between the shadows is comparatively large. Among 

 other communications in the same journal we may mention M. 

 Cornu's address on the discovery of minor planets by 

 photography, M. Flammarion on the spring of 1893, some 

 notes on the late total solar eclipse, and a brief reference to a 

 proposed new astronomical station on Mount Mounier, at an 

 altitude of 2800 metres. 



GEOGRAPHICAL NOTES. 



Mr. F. G. Jackson, whose proposed attempt on the North 

 Pole by Franz Josef Land has been announced, has altered his 

 plans. He now proposes to spend next winter in Nova Zembla, 

 in order to familiarise himself with the conditions of Arctic life, 

 and to test his sledges and other appliances for travelling over 

 the ice. His more serious journey in Franz Josef Land has been 

 postponed for a year, and will have a greatly increased chance 

 of success. 



ViT.\ Hassan, well known as Emin Pasha's apothecary in 

 the Equatorial province, died recently. He had published a 

 book on affairs in the Sudan, which throws some new light on 

 the history of the Egyptian provinces before Stanley's expedition 

 reached the Albert Nyanza. 



A LADY traveller. Miss Taylor, of the China Inland Mission' 

 has made a somewhat remarkable journey in Eastern Tibet' 

 details of which will be looked for with much interest. Mis* 

 Taylor, w ho travelled alone, is expected soon to arrive in this 

 country. 



A Geographical Club has recently been established in 

 Philadelphia, which practically constitutes a new geographical 

 society. It has published the first number of a bulletin contain- 

 ing a paper by Mr. E. S. Balch on moun'.ain exploration, in 

 which he endeavours to redeem mountaineering from the charge 

 of being only a dangerous pastime. 



The coral reefs of Dar-es-Salaam, on the east coast of Ai'rica, 

 have beencarefully studied by Dr. Ortmann, whose observations 

 extend considerably our knowledge of fringing reefs. 



THE ROYAL SOCIETY SOIREE. 



''PlIE President of the Royal Society received a brilliant 

 company at the Society's rooms on the occasion of the 

 annual ladies' soiih on June 7. Many of the exhibits were 

 shown at the conversazione of May 10, and were noted in 

 Nature of May 18. Other exhibits are described in the 

 following account : — 



Mr. C. J. Woodward exhibited a bar over a resonance 

 chamber illustrating sound interference. When a ventral 

 segment is over the box a loud deep tone is heard. When the bar 

 is placed so tliat a node is near the centre of the opening to the 

 box no sound is heaid, owing to opposite movements o( the bar 

 on either side of the node. 



The Karakoram Mountain Survey Expedition exhibited 

 Water-colour Drawings of the scenery of the Karakoram 

 Mountains, Kashmir, India, by Mr. A. D. McCormick. 

 These drawings were made at altitudes of from 15,000 to 

 20,000 feet, during the Expedition in 1892. 



Prof. Osborne Reynolds, F. R. S., exhibited an illustration of 

 vortex motion showing motion analogous to vortex rings in fluids. 



Prof. Thorpe, F. R.S., exhibited autotype enlargements 

 from photographs taken by himself, illustrative of the recent 

 African Eclipse Expedition. The enlargements portrayed— (l) 

 the eclipse party ; (2) the observing party at Fundium, Senegal — 

 taken immediately after the eclipse ; (3) the duplex corona- 

 graph ; (4) the prismatic camera ; (5) the integrating photometer ; 

 {6) the equatorial photometer. 



Capt. McEvoy exhibited the hydrophone. This, in connec- 

 tion with a new instrument named a kinesiscope, is intended to 

 be used at night, or in foggy weather; it has for its object the 

 prevention of surprise attacks from torpedo-boats, or other 

 hostile vessels, approaching anchorages, or mine-fieldj. It will 

 give warning of their movements when they are several miles 

 distant by ringing bells, fl.ishing lights, &c. These signals in 

 every case are verified by telephones in the circuit. The 



NO. 1233, VOL. 48] 



apparatus, which is electrical, may also be employed to warn 

 vessels off dangerous points of the coast. 



Dr. John Gorham exhibited a reflecting kaleidoscope, which 

 is a new instrument adapted to produce not merely syminetric 

 patterns of beauty, but to exemplify many of the theories in 

 optics connected with the reflections of light. To do this 

 changes in its construction are required to adapt it to its novel 

 u'-es. The two mirrors, for instance, must be thrown open to 

 admit the light upon them and the objects. The objects them- 

 selves must have a definite shape to cause them to reflect 

 oblique rays of light only, while the light again must fall upon 

 them from above, instead of being transmitted through them 

 from below. These objects consist of strips of card bent back- 

 wards and forwards into hollows and elevations, upon which the 

 light falls obliquely. It is then received upon the mirrors and 

 reflected from them to the eye. Experiments were made to 

 show: — (l) Gray tones from oblique white surfaces; (2) tints 

 and shades of colour from oblique coloured surfaces ; (3) depth, 

 intensity, and brilliancy by repeated reflections ; (4) the choice 

 lustre, &c. 



Mr. Edwin Edser exhibited an apparatus to illustrate Prof. 

 Michelson's method of producing interference bands. Light 

 is allowed to fall on a mirror thinly silvered, so that about half 

 of the light is reflected and half transmitted. The two rays 

 pursue paths which are mutually perpendicular, are reflected 

 back by two ordinary mirrors, and on meeting interfere. The 

 interference bands can be projected on a screen, and this fact 

 together with the simplicity of the arrangements will make the 

 metho<l very useful for lecture illustration. 



Mr. W. A. Shenstone and Mr. M. Priest exhibited an 

 apparatus used for studying the action of the electric discharge on 

 oxygen. A known volume of oxygen at known temperature and 

 pressure is exposed to the " glow " discharge at known difference 

 of potential. The change- of pressure is read by a mercury 

 manometer, and from this the proportion of ozone is calculated. 

 The use of the mercury manometer, hitherto impo.-sible, makes 

 this method very accurate, and by means of it our knowledge of 

 the influence of various conditions (such as difference of potential, 

 rapidity of discharge) has been considerably extended. It is 

 found that under equal conditions a coil is more effective than a 

 " Wimshurst " or '• Voss " machine. The using of mercury in 

 the manometer is made possible by protecting it from the ozone 

 by placing a rod of silver in the lube connecting the ozone 

 generator and the manometer. 



Mr. Percy E. Newberry was in charge of an exhibit by the 

 Egypt Exploration Fund (Arclu-eological Survey). The exhibit 

 included water-colour drawings executed by the artists of the 

 survey — Mr. Percy Buckman, -Mr. John E. Newberry, and Mr. 

 Howard Carter — during the past season, 1892-3. (l) Sketches 

 of various sites visited by the officers of the survey, including 

 views of Tell el Amarna, Sheikh Said and Der el Gebrawi. (2) 

 Specimens of facsimile drawings of wall paintings from ancient 

 tombs in the provinces of Minieh and Assiut (VI. and XII. 

 dynasties, B.C. 3800 and B.C. 2500). 



Lord Kelvin, Pres. R.S., exhibited illustrations of the mole- 

 cular tactics of a crystal. (l) Bravais homogeneous assemblage 

 of 512 single points. (2) Two homogeneous equilateral as- 

 serpblages of points, red and green, with stretched springs 

 between each point of the green assemblage and its nearest neigh- 

 bour, and four struts between each of the reds and its nearest 

 neighbour of the green assemblage ; showing how any degree of 

 resistance to compression with given rigidity can be provided for 

 by Boscovich's theory. (3) Three-dimensional netting, analogous 

 to the ordinary hexagonal netting of two dimensions. "The 

 stretched cords of this model are exactly in the positions of the 

 struts of model No. 2. (4) Twelve nearest and eight next- 

 nearest neighbours of an ideal particle at the centre of a cube, 

 placed to .show the cubic arrangement of an equilateral 

 assemblage. (5) Cubic cluster of fourteen balls, being the least 

 number which can show cubic form in an equilateral assemblage. 

 (6) Probable molecular structure of Iceland spar. (7) Illustrat- 

 ing the molecular movement in the twinning of Iceland spar 

 by knife according to Baumhauer. (8) Illustrating B.aunihauer's 

 artificial twinning of Iceland spar by knife, (g) Tetrahedron 

 with adjustable edges vsix independent variables). (10) Two 

 geometrical models of: — (a) A dextro-chiral crystal. (M A 

 levochiral crystal. (11) Special tetrahedron, with perpendicu- 

 lars from corners to faces, meeting in one point ; to illustrate 

 engineering of Boscovich's theory for an incompressible elastic 

 crystal with 12 arbitrarily given rigidity moduluses. 



Dr. G. 11. Fowler exhibited specimens of oyster shells. The 



