April 26, 1894] 



NA rURE 



617 



researches of Mr. Murray, Dr. H. R. Mill, and others, that al^ 

 these necessary correlations actually existed, although hitherto 

 some of them had been looked upon as mere curious and inex- 

 plicable coincidences. 



But if the fold or wave rules in the arrangement of the forms 

 of the earth-surface of the present day, it must of necessity rule 

 also in corresponding planetary surfaces, both in space and time ; 

 and the author gave it as his opinion that it afforded an equally 

 natural and plausible explanation of cycles, systems, and trans- 

 gressions of the geological formations, and of the surface (for 

 example) of the planet Mars. 



The final conclusion which the author drew from a consider- 

 ation of the known facts and phenomena was, that the wave or 

 fold appeared to be the natural unit of classification of all the 

 grander forms of the earth-surface. The recognisable surface 

 undulations of the present earth-surface are, broadly speaking, 

 the surfaces of corresponding waves or warpings of the 

 outer parts of the earth-crust, in part obliterated by 

 erosion, &c. , and in part masked by deposition. In the 

 crust-wave, its divisions, modifications, combinations, and 

 intersections, we seem to find the key to the dissymmetries, 

 the harmonies, the contrasts, and even the supposed anomalies 

 of the surface features of the globe. Upon the surface of the earth, 

 the crust-deformation expressible in terms of this unit seems 

 to be the paramount factor. Denudation, deposition, earth- 

 quake movement, volcanicity, and even the surface forms and 

 oistributions of the main land and water areas, appear to be all 

 subordinated to this ruling element. As the minor undulations 

 stand related to the major undulations as subordinates, it is pro- 

 bable that not the slightest local change can be brought about 

 wichout disturbing to that extent the balance of parts, and so 

 leading to a readjustment of the equilibrium of the whole. The 

 fold theory, however, affords us merely a natural and convenient 

 means of classification of surface form, and in the meantime 

 does not concern itself with the mode of origin of these forms. 

 It is a theory, not of causes, but of the most natural grouping 

 of effects. 



SCIENTIFIC SERIALS. 



American yournal of Science, April. — Further studies of 

 the drainage features of the Upper Ohio basin, by T. C. 

 ' Chamberlin and Frank Leverett. The general view adopted is 

 that of Carll, according to whom the present drainage system of 

 the Upper Ohio basin has been formed by the union of several 

 pre-glacial systems that formerly flowed into what is now the 

 Lake Erie basin. These were blocked up by the ice of the earlier 

 glacial period, which invaded their lower courses and forced 

 them to flow over low divides and unite to form a common 

 south-westward flowing system nearly parallel to the border of 

 the ice. The evidence for reversals and displacements of 

 river beds is given in detail, and four hypotheses are presented 

 to account for them. They all greatly emphasise the importance 

 of the first glacial epoch, and indicate that, while the last glacial 

 invasion was very much more pronounced in its apparent effects, 

 it was, after all, much the smaller factor in the glacial period. — 

 An apparatus to show, simultaneously to several hearers, the 

 blending of the sensations of interrupted tones, by Alfred M. 

 Mayer. A short brass tube is cemented in a hole in the bottom 

 of a glass flask. When the tube is closed the flask resounds 

 powerfully to a tuning-fork of suitable pitch vibrating near its 

 mouth. When the tube is open the resonance is very feeble. 

 The opening and closing is effected by a perforated disc rotating 

 in contact with the brass tube. At a certain velocity the in- 

 terrupted sounds blend into the sound of the tuning-fork, the 

 velocity giving an indication of the amount of residual sensation. 

 — The appendages of the pygidium of Triartkrus, by Charles 

 E. Beecher. Further studies of the Yale Museum specimens 

 have enabled the author to make out the main characteristics 

 of the appendages of the caudal shield. At the pygidium, the 

 endopodites preserve the slender, jointed, distal portion found 

 at the thorax, but the proximal part is composed of segments 

 which are considerably expanded transversely, thus making a 

 paddle-like organ, the anterior edge of which is straight, while 

 the posterior one is serrated by the projecting points of the ex- 

 panded segments. These points bear small bundles of setK. 

 The specimens from which these details are gathered are very 

 perfectly preserved. The author proposes next to describe the 

 structure of the under side of the head, and then to review the 



NO. 1278, VOL 49' 



present enlarged knowledge of Triarthrtis, with its bearings 

 upon the position and affinities of the Trilobites generally. 



Bulletin de r Acadcmie Royale de Belgiqiie, No. 2. — The sense 

 and the period of the Eulerian movement, by F. Folie. The 

 sense of the Eulerian movement of the pole of inertia round the 

 instantaneous pole is direct ; that of the movement of the in- 

 stantaneous pole at the surface of the earth is retrograde. The 

 period of the latter is 321 days ; for an integral number of 

 years, a direct and somewhat slower motion may be substituted 

 for this, giving the commonly accepted period of 423 days. 

 But the shorter period is free from the geometrical objections 

 attached to the latter. — The influence of pressure upon specific 

 heat, taken below and above the critical temperature, by P. de 

 Heen. The law governing this influence is analogous to that 

 determining the relation between pressure and compressibility. 

 Little variable at first, the specific heat rises with increasing 

 pressure up to a certain limit, and then diminishes. — On the 

 phenomenon of beats in luminous vibrations, by Dr. J. 

 Verschaffelt. Prof. Righi showed in 1S78 that if two rays are 

 brought to interference whose periods are only slightly different, 

 fringes are obtained which move with such velocity that a num- 

 ber equal to the difference of frequency passes each point of the 

 screen in one second. Righi realised this practically by means 

 of a rotating XicoU prism and Fresnel's mirror. The principle 

 applied by Dr. Verschaffelt is that of Doppler, according to 

 which a motion of the source with respect to, the ether changes 

 the wave-length of the light emitted. The retardation was 

 produced by a moving wedge of quartz cut parallel to its axis, 

 and placed at 45' between the crossed Nicolls of a polarising 

 microscope. — On absorption by the bile ducts, by Celestin 

 Tobias. Ligature of the thoracic canal suppresses absorption of 

 acids and biliary pigments, as pointed out by Harley. But it 

 does not affect that of sodium ferrocyanide, of strychnine, or of 

 atropine at the surface of the bile ducts. Sodium iodide is not 

 absorbed at all. Whether the absorption is lymphatic or 

 sanguine depends upon the nature of the substance. 



SOCIETIES AND ACADEMIES. 



London. 



Physical Society, April 13.— Prof. A, W. Rucker, F.R.S., 

 President, in thechair. — The President invited discussion on Prof. 

 Henrici's paper on calculating machines, and said a description 

 of Mr. Sharp's harmonic analyser, giving direct readings of the 

 amplitude and epoch of the varioas constituent simple 

 harmonic terms, had been sent in. This machine requires no 

 adjustments to be made before using. The amplitude is given 

 by the length of a line joining the initial and final positions of the 

 point of contact of a roller with a rotating disc, whilst the epoch 

 IS determined by the angle which this line makes with the plane 

 of the rollerinitsinitial position. — Prof Perry congratulated Prof 

 Henrici on the success attained with his analysers. lieferring 

 to planimeters, he said the average error made in working out 

 indicator diagrams with Hine and Robertson's instrument was 

 only about one-third that made with Amsler's. After pointing out 

 the great importance of Fourier's series to practical men, and 

 especially to electrical engineers, he said that in studying re- 

 ciprocating motions, 'such as those of pistons, valve gears, &c. , 

 it was most useful to resolve the motion into its fundamental 

 harmonic motions and its overtones. In this way remarkable 

 differences could be seen between various motions which have 

 the same fundamental, and which are usually considered 

 equivalent. In the Electrician of February 5, 1892, he had 

 published the numerical work for a given periodic curve 

 developed in Fourier's series, and he now exhibited a graphical 

 solution done by one of his students, who was probably the first 

 to carry out the late Prof Clifford's idea of wrapping the curve 

 round a cylinder and projecting it on different planes. Prof. 

 Henrici had, he said, based the construction of his first analyser 

 on Clifford's method, but used the Henrici principle (viz. 



y sin 6 dd = I cos B dy, when integrated over a complete 



period) to explain the later machines. As a matter of fact the 

 first machine in which the coefficients were determined by an 

 Amsler planimeter carried by a reciprocating tangent plane, was a 

 beautiful example of the Henrici principle, and he. Prof. Perry, 

 saw far greater possibilities before it. The defects in the first 

 instrument were mechanical ones, and could be got over by in- 



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