May 19, 1887] 



NATURE 



67 



Captain Wharton, Hydrographer of the Admiralty, exhibited 

 un-signalling apparatus, designed by Mr, F. Galton, F. R.S., 

 the use of naval surveyors. The optical arrangements are 

 i same as those described by him in the Journal of the British 

 ;sociation, 1858, but the movements are new. Its advantage 

 the facility it affords for accurate direction of the beam of 

 ht ; an image of the sun appearing over the object to which 

 is desired to flash, when viewed through the telescope, 

 ipt. Wharton also showed a set of charts illustrating the 

 drographical conditions of coral reefs and islands that stand 

 deep water ; a new chart of the south circumpolar regions, 

 th tracks of explorers ; and a chart showing sea-surface 

 Tiperatures obtained off the north-west coast of Spain, June to 

 ptemher 1886. An improved pneumatic tide-gauge or level- 

 licator was exhibited by Capt. de Wolski. This enables the 

 jistering apparatus to be ?t any distance, horizontal or vertical, 

 )m the spot in the sea below low-water mark where the tide 

 measured. Specimen charts (of which we have already given 

 me account), exhibiting the conditions of weather over the 

 lantic Ocean at the four seasons of the year, were shown by 

 e Meteorological Council, (i) Daily synchronous charts of 

 North Atlantic in spring, February 27 to March 4, 1883. 

 lese charts show that an anticyclone lies over Western 

 irope, and the neighbouring part of the Atlantic, with much 

 Im and fog prevailing at its centre ; whilst the predominant 

 nds in these islands are northerly and easterly, typical March 

 iather. (2) Daily synchronous weather charts of the North 

 tlantic in summer, August i to 6, 1S82. These charts exhibit 

 e prevailing area of high barometrical pressure on the eastern 

 le of the Atlantic, which is related to a prevailing north 

 2sterly wind at the entrance of the Channel, changing to north 

 f the coast of Portugal, and eventually merging in the north- 

 st trade. (3) Daily synchronous weather charts of the 

 orth^ Atlantic, in autumn, October 9 to 14, 1882. The 

 imerous small areas of low barometrical pressure over the 

 a on these charts, which appear at the time of year 

 tien the region of highest pressure is about to be transferred 

 )m the ocean to the land, seem to indicate what takes place 

 iring the change. Several small cyclonic systems are shown 

 the southern part of the area of high pressure which prevails 

 er the Atlantic in about 30° N. (4) Daily synchronous weather 

 arts of the North Atlantic in winter, February 9 to 14, 1883. 

 iie part of the Atlantic north of 40"" N. is affected by a large 

 ea of low pressure, of which the centre lies somewhere to the 

 uthward of Iceland. These conditions are usual in winter, 

 aps of the English dialect districts, with key, by Mr. Alexander 

 Ellis, to illustrate bis "Existing Phonology of English 

 ialects," not yet published, were exhibited by the author. Mr. 

 ■ank Crisp exhibited tarly microscopes :—(i) Campani's 

 icroscope. No field lens, and probably the earliest microscope 

 tant. (2) Pope Benedict's microscope. Belonged to Cardinal 

 imbertini, afterwards Pope Benedict XIV. Triple crown and 

 oss keys inlaid in front of box. (3) Hooke microscope. This 

 so belonged to the same Pope. (4) Oppelt's microscope, 

 istruments for measuring extensions and compressions in 

 aterials subjected to stress were exhibited by Prof. W. C. 

 nwin. (i) Apparatus to measure extensions to i/io,ooo of 

 I inch. Two clips embrace the bar, so that the movement of 

 e middle points is the mean of the extensions on both sides, 

 he clips are set level by sensitive levels, and the distance be- 

 een them is measured by a micrometer screw. (2) Apparatus 

 measure extensions. The bar is embraced by clips, so that a 

 ean of the extensions on each side is taken. The extensions 

 e measured by a roller and mirror. Measures to 1/100,000 

 an inch. (3) Similarly arranged apparatus for compressions, 

 he strain is measured by a microscope micrometer. Measures 

 50,000 of an inch. Apparatus for the drawing of automatic 

 ress-strain cui-ves was shown by Prof. Kennedy. In this 

 )paratus the bar to be tested is extended " in series " with a 

 uch stronger bar of steel. This bar is used as a spring, and its 

 astic extensions, magnified by a light pointer, are taken as 

 oportional to the stress in the test-bar, and recorded by the 

 id of the pointer on a sheet of smoked glass which has a motion 

 right angles to that of the points,' and proportional to the elonga- 

 )n of the test bar. There is also a special arrangement of differen- 

 d levers to eliminate any errors in this motion which might arise 

 om the extension or " give " of other parts of the instrument. 

 Forty-six photographs of clouds in many parts of the 

 jrld were exhibited by the Hon. Ralph Abercromby, by whom 

 ey were photographed. These were mostly taken during two 



voyages round the world for meteorological research. The pic- 

 tures illustrate very clearly the identity of cloud-forms all over 

 the world, for similar cumulus and cumulo-nimbus forms range in 

 latitude from London to near Cape Horn — including one actually 

 on the equator ; and the stratus from Sweden to New Zealand ; 

 while the mists in the Himalayas are indistinguishable in general 

 character from those of Great Britain. In addition to illustrations 

 from the countries above mentioned, clouds are represented from , 

 Teneriffe, Brazil, the Falkland Island."^, the Indian Ocean, and 

 Borneo. Model of high-speed hydraulic or steam engine for driv- 

 ing electric light, and other purposes, was exhibited in motion by 

 Mr. Arthur Rigg, the inventor. Reciprocation of pistons, and 

 other moving parts, imposes an early limit to speed in engines 

 of ordinary construction, so it has long been an unsolved problem 

 how to produce a satisfactory engine without this evil, no rotary 

 engines having ever yielded results encouraging their adoption. 

 The revolving engine possesses pistons and cylinders, which are 

 the best mechanical contrivance for remaining steam tight or 

 water tight, and these have reciprocations relative as between 

 each other, but only rotation in relation to the earth, while the 

 cylinders and pistons revolve each on their own independent 

 centres. The static balance and the dynamic balance are iden- 

 tical, and this engine therefore runs in equilibrium, without 

 vibration, and in almost perfect silence. It is governed by 

 varying the rate of expansion in the case of steam, or by varying 

 the length of stroke in the case of water, and produces very 

 economical results. It has none of that rhythmical variation in 

 speed which occurs during each revolution of an ordinary engine. 

 It is the only engine hitherto invented which can be driven at 

 high speed by water pressures of considerable amount, and is 

 found to give a perfectly steady incandescent light when making 

 250 revolutions per minute, driving a dynamo for 100 lamps, and 

 worked by 700 lbs. per square inch water pressure. Prof. 

 Forbes's thermo-galvanometer, made by Messrs. Nalder Bros, 

 and Co., was exhibited by Prof. George Forbes. This consists of 

 a ring, half of antimony, half of bismuth, one of the soldered 

 junctions being filed thin and blackened to receive radiations. 

 The conductivity of the ring is increased by the addition of a 

 block of copper. A light Thomson magnet and mirror, sus- 

 pended by a silk fibre, is placed inside the ring. The present 

 form of instrument is rendered astatic by means of a second 

 magnet. Prof. Forbes also showed specimens of electric welding 

 by Prof. Elihu Thom-on, of Boston, U.S.A. Some of Dr. J. 

 Puluj's remarkable vacuum tubes, made by Miiller, of Bonn, 

 were exhibited by Mr. Warren De la Rue, and Dr. Hugo 

 Miiller. (i) Electrical radiometer with phosphorescent vanes. 



(2) Electrical radiometer with phosphorescent rotating disk. 



(3) Electrical radiometer with two phosphorescent rotating disks. 



(4) Electrical radiometer with rotating bell-glass. (5) Phos- 

 phorescent lamp. Speciinens illustrating the effect of great 

 earth-movements upon the pebbles contained in rock-masses 

 were exhibited by Prof. J. W. Judd. (i) Series of impressed, 

 faulted, crushed, and polished quartzite pebbles from the old 

 red sandstone, near the great faul', Stonehaven, N.B. (2) Im- 

 pressed limestone pebbles from the Swiss nagelflue (3) Faulted, 

 crushed, and re-cemented flints from the chalk. (4) Pebbles from 

 Bunter conglomerate, crushed and scratched by earth-movements. 

 Specimens and microscopic sections of carboniferous chert, filled 

 with spicules of siliceous sponges, were exhibited by Dr. G. J. 

 Hinde. Beds of chert are largely developed in the carboniferous 

 rocks of Yorkshire, North Wales, and Ireland, between the 

 horizon of the carboniferous limestone and the millstone grit. 

 In Flintshire they attain a maximum thickness of probably not 

 less than 350 feet. These strata are of organic origin, and built 

 up mainly of the detached skeletal spicules of siliceous sponges, 

 which, for generation after generation, lived and died on the 

 sea-bottom in these areas, and by the gradual accumulation of 

 their microscopic spicules formed the rocks. Maps and sections 

 of the Geological Survey of the United Kingdom were exhibited 

 by Mr. Arch. Geikie, and a MS. geological map of the British 

 Isles, for the geological map of Europe now in preparation by 

 the International Geological Congress, was shown by Mr. William 

 Topley, of the Geological Survey of England. Scale, i : 1,500,000 

 (i inch to 23J miles). The map will be in forty-nine sheets, in 

 all about 12 feet by 10 feet. The cost of producing the map is 

 contributed by the various Governments of Europe. England's 

 share of the expense is ^400, instalments of which are given, as 

 required, by the Royal Society from its Government grant. 

 For this sum a hundred copies of the complete map will be sent to 

 the Royal Society. A drawing of a specimen showing the assump- 



