74 



NATURE 



[March i6, 191 6 



Avhich the rivers flow in a series of waterfalls, cascades, 

 and rapids. This plateau is terminated inland by de- 

 graded cliffs rising abruptly from 400 ft above sea- 

 level, while the plain slopes gently to the recent sea- 

 cliffs, mostly more than 300 ft. high. The plateau has 

 been cut across rocks of different degrees of hardness, 

 and is overlain by deposits of detritus and peat. Wher- 

 ever the plain occurs, the scenery is featureless, and 

 the land boggy and waterlogged. The widespread 

 occurrence of this plain over Cornwall and Devon at 

 a uniform height suggests that in its final stages it 

 was a plain of marine erosion. There are in Cornwall 

 and Devon two characteristic types of scenerj-, to which 

 in great part these counties owe their charm. Wide 

 featureless plains covered with heath and marshland 

 and dominated by tors and crags, on which the 

 •drainage is sluggish and vague, alternate with deeply- 

 incised rocky ravines where rivers flow as rapids and 

 cascades. These two types mark successive periods of 

 •erosion. Post-Pliocene uplift gave such increased 

 cutting-power to the rivers that thej^ quickly incised 

 chasms in their former valleys, employing while so 

 doing the activity of waterfalls and rapids. 



Linnean Society, March 2. — Prof. E. B. Poulton, 

 president, in the chair.— Dr. J. D. F. Gilchrist : Larval 

 and post-larval stages of Jasus lalandii (Milne- 

 Edwards). Dr. Gilchrist recalls his description, in 

 Journ. Linn. Soc, October, 19 13, of the newh-hatched 

 larva, to which he applied the term naupliosoma. He 

 now recognises that this name was rather inappro- 

 priate, since it tends to obscure the reasonable pre- 

 sumption that the naiiplitis stage has " been passed 

 long before in the development of the embryo." By 

 a record of the distribution, he makes it fairly certain 

 that the further stages of development with which 

 lie deals realh^ belong to Jasus lalandii. It should, 

 however, be mentioned that, whatever the predomin- 

 ance of this particular crawfish at the Cape, the Atlan- 

 tic is in some parts well provided with various mem- 

 Ijers of the families Scyllaridae and Palinuridae. — B. M. 

 Griffiths : The August Heleoplankton of some North 

 Worcestershire pools. — Dr. O. Stapf : The distribution 

 of the box-tree, Buxus senipervirens, Linn. The 

 author adopted Dr. Christ's views as to the character 

 of the box as a relict of the Tertiary flora of southern 

 Europe, and the discontinuous distribution as brought 

 about b}^ disintegration of an old continuous and 

 much larger area. But he could not share his view 

 that the isolated stations in western France are gener- 

 allv due to old plantations around castles and monas- 

 teries. He considered them like the English stations 

 as relict stations. 



Mathematical Society, March 9. — Sir Joseph Larmor, 

 president, in the chair.^ — Major P. A. MacMahon : Some 

 applications of general theorems of combinatory 

 analvsis. — Prof. H. F. Baker : Mr. Grace's theorem on 

 six lines with a common transversal. — H. E. J. Curzon : 

 The integrals of a certain Riccati equation connected 

 with Halphen's transformation. — Miss Hilda P. 

 Hudson : A certain plane sextic. — Dr. W. P. Milne : 

 The construction of coapolar triads on a cubic curve. 

 — J. Proudman : The dynamical equations of the tides. 



Manchester. 

 Literary and Philosophical Society, February 22. — Prof. 

 G. Elliot Smith, vice-president, in the chair. — Prof. 

 W. W. Haldane Gee : Bunsen and luminous flames. 

 .\ small obstacle placed at the centre of a coal-gas 

 flame (issuing from a small circular nozzle) at a 

 critical distance above the aperture, gives rise to a 

 musical note of high frequency. If tw-o such flames 

 are made to impinge, roaring or musical flames result. 

 Burners of the Bray and M^ker type possess special 

 properties. One experiment of great interest enabled 



NO. 2420, VOL. 97I 



the eddy currents produced by a flame from a triple 

 nozzle to be studied. When the flame is adjusted — 

 so as to be central within a wide glass tube — carbon- 

 aceous particles are precipitated from the flame, and 

 these are whirled in an infinite variety of curves round 

 the flame mantle. The effect is more marked when 

 benzine is introduced into the coal-gas. — -Dr. J, H. 

 Smith : A resume of work on the bleach-out process 

 of colour photography. Grothus, in 1819, seems to 

 have been the first to attempt to formulate the nature 

 of the action of lights of different colour upon bodies, 

 and showed that coloured bodies faded most rapidly in 

 the " opposed " (complementary) coloured light to their 

 own. Liesegang, in 1889, first proposed to utilise this 

 principle in the case of the bleaching-out of aniline 

 dyes in their complementary coloured lights for the 

 production of coloured prints upon paper from trans- 

 parent coloured pictures. Vallot, in 1895, Neuhaus 

 and Worel, in 1902, and later Szczepanik and the 

 author worked practically upon this process, over- 

 coming some of its difficulties, and obtaining certain 

 results of a somewhat crude nature. In 1907 the 

 author brought the first bleach.-put paper upon the 

 market; and in 191 1 he was successful in bringing 

 out a new paper (" Utocolor "), b}' means of which 

 good prints from autochrome plates could be obtained. 

 The more recent work of Limmer, Gebhart, and Just 

 was review-ed. 



Dublin. 

 Royal Dublin Society, February 22. — Prof. Sydney 

 Young in the chair. — Prof. Wm. Brown : The subsh- 

 dence of torsional oscillations of nickel wires when 

 subjected to the influence of transverse magnetic fields 

 up to 200 c.g.s. units. A direct transverse magnetic 

 field of 200 c.g.s. units has no effect on the damping 

 of torsional oscillations of a nickel wire whether the 

 wire be hard or soft, but an alternating transverse 

 magnetic field of the same strength increases the 

 damping by almost 10 per cent, in a soft wire and by 

 about 4 per cent, in a hard w'ire. For a transverse 

 alternating magnetic field of 65 units, it was found 

 that when the frequency of the field was increased 

 eight times the damping was decreased, that is, the 

 amplitude of the seventieth vibration was increased 

 about 45 per cent. 



Royal Irish Academy, February 28. — Rev. J. P. 

 Mahaffy, president, in the chair.— J. J. Nolan ; The 

 mobility of the ions produced by spraying distilled 

 water. When distilled water is passed through a 

 sprayer the larger drops have a positive charge of 

 uniform surface density, as shown in a previous paper. 

 The present paper deals with the mobility of the ions 

 carried away in the air from the sprayer. Twelve 

 groups of ions have been found, each group possess- 

 ing a distinct mobilit}- which changes little with time. 

 The mobilities are 000038, oooio, 0-0043, 0013, 0046, 

 012, 024, 053, i-i, 156, 327, and 65 cm. per second 

 in a field of i volt per cm. Ions of both signs occur 

 in all the groups with the exception of the group of 

 mobility 65, w-hich has only been found with negative 

 charges. The negative charge carried by the ions 

 exceeds the positive, the excess being greater in the 

 case of the more mobile ions. — J. A. McClelland 

 and P. J. Nolan : The nature of the ions 

 produced by bubbling air through mercury. 

 The mobility of the ions carried away in 

 air which has bubbled through mercury has been 

 measured. The mobility decreases rapidly with time, 

 and in this respect differs from the results obtained 

 in the above paper on the spraying of water. When 

 sufficient time, has elapsed constant mobilities are 

 reached, and groups of ions have been found corre- 

 sponding to the first five groups in the above paper. 

 When measured earlier greater mobilities are found, 



