530 



NA TURE 



[March 29, 1900 



observed. By means of an optical experiment, the author has 

 found that O'l of a division on the graduated head equals 

 I '033 ^).n at the platino-iridium ppint. The point and the dia- 

 phragm then formed part of a circuit containing an ordinary 

 telephone, and the levers were so adjusted that the point just 

 touched the diaphragm. A sharp click was then heard in the 

 telephone. A small current was then sent through the electro- 

 magnets of the original telephone, and the displacement of 

 the diaphragm measured by turning the spherometer screw 

 until the point just touched it and a second click was heard. 

 By carrying out a series of experiments of this description, a 

 curve has been drawn showing the relation between current 

 strength and diaphragm displacement. It is then interesting, 

 by exterpolation from the curve, to find the movement which 

 corresponds to the least audible sound. The author has done 

 this, and finds that he cannot hear sounds if the amplitude is 

 less than o"37 ju/i. A motion of 50 yUjit gives comfortable sounds, 

 1000 fxix uncomfortable sounds, and 5000 |UjU sounds unbearably 

 loud. Throughout the experiments it was necessary to get rid 

 of extraneous vibration by means of indiarubber balls and door- 

 spring suspensions, and by working at night. Prof. Everett 

 expressed his interest in the delicacy of the system of measure- 

 ment, and asked if the micrometer had been used to determine 

 .the form of the plate when vibrating. Mr. Phillips asked if 

 experiments on the smallest sound audible had been made on 

 different people, as it would be physiologically interesting to 

 know if this minimum value were constant. Mr. Campbell 

 asked if the sound was expected when heard. Mr. Shaw said 

 he had not conducted experiments on the form of the plate 

 when vibrating, although he had investigated its law of damp- 

 ing. He said the small sounds were expected and the limit 

 varied. The chairman said he found it easy to rid galvano- 

 meters and electrometers from extraneous disturbance by placing 

 them on a block of stone resting on a thickness of three or four 

 feet of slag wool contained in a hollow brick pillar. — The Society 

 then adjourned until April 27, when the meeting will be held 

 at eight o'clock in the Solar Physics Observatory of the Royal 

 College of Science. 



Chemical Society, March 8. — Prof, Thorpe, President, in 

 the chair. — Prof. Warington delivered a lecture on recent 

 researches on nitrification. 



March 15. — Prof. Thorpe, President, in the chair. — The 

 following papers were read : — The vapour densities of dried 

 mercury and mercurous chloride, by H. B. Baker. Carefully 

 dried mercurous chloride seems to have the molecular com- 

 position HgaCLi at 448°, thus differing from the undried 

 material, which is known to dissociate at this temperature. 

 Carefully purified and dried mercury is monatomic at 448". — 

 The preparation of pure hydrobromic acid, by A. Scott. 

 Pure hydrobromic acid is very conveniently prepared by the 

 action of sulphurous acid upon bromine, the product being 

 easily separated, by two or three distillations, from the sulphuric 

 acid simultaneously formed. — A new sulphide of arsenic, by 

 A. Scott. On allowing an arsenate to react with phosphorus 

 trichloride and sulphurous acid at ordinary temperatures a 

 dark brown precipitate is formed, which consists of a new 

 arsenic sulphide having the composition AsgS. — The action 

 of iodine on alkalis, by R. L. Taylor. The author 

 shows that the action of iodine upon alkalis in 

 the cold is always the same in the first instance, and 

 consists in the formation of hypoiodite and iodide ; the 

 hypoiodite, however, decomposes more or less rapidly, according 

 as the solution is more or less concentrated, into iodate and 

 iodide. — The interaction between sulphites and nitrites, by E. 

 Divers and T. Haga. — The sym-dipropyl, sym-diisopropyl- and 

 aa'-propylisopropyl-succinic acids, by W. A. Bone and C. H. G. 

 Sprankling. The authors show that, contrary to the re- 

 ceived view, each of the above alkyl-substituted succinic acids 

 exists in two stereoisomerides ; both cis- and />a«j--isomerides 

 yield their own anhydrides with acetic chloride, and the an- 

 hydrides give characteristic anilinic acids with aniline. — Manno- 

 galactan and laevulo-mannan ; two new polysaccharides, by 

 J. L. Baker and T. H. Pope. The Indian clearing nut {Strychnos 

 potatortim) yields an amorphous manno-galactan on extraction 

 with hot dilute alkali ; the new substance gives a mixture of 

 two parts of galactose to one of mannose on hydrolysis. The 

 ivory nut {Pliytelephas macrocarpa) similarly yields a laevulo- 

 mannan which on hydrolysis gives a mixture of twenty parts of 

 mannose with one of Icevulose. — Hydrolysis of semicarb- 

 azones, by G. Young and E. Witham. — The dissociation 



constant of azoimide, by C. A. West. Determinations of 

 the electrical conductivity of aqueous solutions of azoimide show 

 that ithis substance resembles acetic acid in acid character. — ■ 

 Racemisation occurring during the formation of benzylidene, 

 benzoyl and acetyl derivatives of dextro-ac-tetrahydro-/3-naph- 

 thylamine, by W. J. Pope and A. W. Harvey. During the 

 formation of the benzylidene, benzoyl and acetyl derivatives of 

 dectrotetrahydro-/8-naphthylamine nearly, but not quite, all of 

 the material undergoes racemisation. 



Geological Society, March 7.— J. J. H. Teall, F.R.S., 

 President, in the chair. — Notes on the geology of Gilgit, by 

 Lieut. -General C. A. McMahon, F.R.S. Briefly stated, the 

 author's conclusions are as follows : — That at one period in the 

 elevation of the Hindu Kush the strata were thrown into a 

 series of folds and compressed into a series of uniclinal beds with 

 a vertical dip. That the direction of the main drainage of the 

 area was determined before, or at the commencement, of the 

 last series of earth-movements that crumpled up the strata. The 

 sedimentary rocks were profusely invaded by granite and diorite, 

 and profoundly metamorphosed by contact-action. As regards 

 the age of the rocks, the author gives his reasons for identifying 

 the Gilgit limestones with the conformable Carbo-Triassic series 

 of the Himalaya. — The rocks of the south-eastern coast of 

 Jersey, by John Parkinson. In this paper the author has con- 

 tinued the study of the deep-seated rocks of Jersey, begun in a 

 communication presented to the Society last session, entitled, 

 "On an intrusion of granite into diabase at Sorel Point 

 (Northern Jersey)." A great resemblance exists between these 

 rocks in the north and south of the island, and it is concluded 

 that they represent parts of the same magma ; but in the south- 

 east additional complications arise, owing to the intrusion of 

 another rock before the invasion of the granite. — The rocks of 

 La Saline (Northern Jersey), by John Parkinson. 



Anthropological Institute, March 13. — Mr. C. H. Read, 

 President, in the Chair. — A photographic slide, presented by 

 Mr. Sidney Hartland, was exhibited, representing the figure of a 

 War God from Boma, in the Congo State (now in the museum of 

 Leyden), into which numerous nails have been driven, probably 

 in registration of the prayers or vows of worshippers. The 

 President compared a similar figure in the possession of Miss 

 M. H. Kingsley, in which the nails were explained as records 

 of lives taken through the magic ])ower of the God. — Mr. A. L. 

 Lewis read a paper on " Stone Circles in Scotland," which he 

 classified according to local types as follows : (i) the Western 

 type, consisting of a single ring of stones with a cist or grave 

 within the enclosure ; (2) the Inverness type (found also locally 

 along the east coast, north of Inverness, and easily accessible 

 thence by sea) with two concentric rings, of which the inner 

 formed the retaining wall of a cairn, under which was a stone 

 lined sepulchral chamber accessible by a stone lined passage ; 

 (3) the Aberdeen type, which differs mainly from that of Inver- 

 ness in the presence of a large slab set vertically between the 

 two largest stones of the outer ring at a point opposite to the 

 passage leading to the chamber. The more irregular circles 

 and alignments, such as Callernish and Brogars, which the 

 author regarded as not primarily sepulchral, and explained as 

 "sun and star" circles, on the ground of their aspect, and of 

 certain proportions which were found to exist among their di- 

 mensions. He insisted upon the ethnological value of the 

 various local types, and upon the importance of testing this by 

 applying a similar classification to the stone circles of England. 

 In discussion, Mr. W. Gowland pointed out that failure to find 

 traces of an interment within a circle did not prove that that 

 circle was not a sepulchral monument originally ; and emphasised 

 the points of agreement between the Western, the Inverness, 

 and the Aberdeen types of circle. Dr. J. G. Garson discussed 

 the modes of determining the age of stone circles, in view of the 

 work of the Stone Circles Committee of the British Association. 

 Mr. G. L. Gomme protested against the premature adoption of 

 an astronomical interpretation of individual monuments. Mr. 

 Lewis briefly replied ; and the President, in returning thanks, 

 dwelt on the necessity of collecting the local traditions as to the 

 original use of these monuments, and at the same time of dis- 

 tinguishing, as in the case of the Yorkshire " Danes Graves," 

 between aboriginal and immigrant sources of tradition. — Mr. 

 J. L. Myres exhibited and described a series of photographs of 

 the megalithic buildings of Malta and Gozo, and pointed out 

 the inapplicability of certain current theories of their origin. 



NO. 



587, VOL. 61 



