Nov. 6, 1879] 



NATURE 



21 



interval, May 5-July 3, 1S77; in the first column arc the daily 

 rates given by the observations, and in the second those resulting 

 from the above formula : — 



May 3- 1 1 



11-25 ■•• 



25-31 ... 

 May 31 -June S 

 June 8-15 



15-19 ... 



19-22 



22-26 



26-29 

 June 29-July 3 



- 0-07 

 000 



- o"04 

 + 0-03 



- o'04 

 + o'2o 



- 0-15 



+ O'lO 



+ 0-09 

 0*05 



- 0'02 

 + O'OI 



- 0'04 



+ o'o6 

 + o - oi 



+ 0-23 



- o - o9 

 + o - n 

 + 0-05 



C04 



Dr. Winnecke remarks that upon the experience in the interval 

 1875-78 he believes the performance of the clock has not been 

 hitherto excelled, and congratulates himself upon the possession 

 of a work of art. 



PHYSICAL NOTES 



Who did discover the attraction caused by the vibrations of 

 sounding bodies? Prof. Guthrie and Herr Schellbach of Berlin, 

 discovered it independently of each other nearly ten years ago. 

 But Guyot had observed the phenomenon before them ; and in 

 a paper in the Philosophical Magazine for 1849, by Mr. Reuben 

 Phillips, on the "Electricity of Steam," the attraction caused 

 by vibration is recorded as a new fact. 



The transverse vibrations of metallic cylinders open at one 

 end have been recently studied by Herr Fenkner, at Marburg 

 ( II ted. Ann., No. 9). The following results were arrived at : 

 The vibration numbers of the tones of such cylinders are i de- 

 pendent of the height of the cylinder. The vibration-numbers 

 of the corresponding tones of two such cylinders are inversely as 

 the squares of the circumferences (or radii), and they are directly 

 as the thicknesses of metal. 



Prok. TGpler, of Dresden, is well known to physicists by 

 his researches on singing flames and by the induction electric 

 machine which bears his name. Topler's machine, of which 

 several examples were shown in the Loan Collection at South 

 Kensington in 1876, resembles in form the more familiar machine 

 of Holt?, and is based upon similar principles. Prof. Topler is 

 at present engaged upon the construction of a larger machine 

 having twenty rotating plates ; and which is capable of gene- 

 rating much larger quantities of electricity. This machine bears 

 a close resemblance to the variety of Holtz machine shown 

 before the Physical Society a few months ago by Mr. W. J. 

 Wilson, and to that recently constructed by Mr. Ladd, which 

 also had a number of plates rotating on a common axis. 



Apparatus for projection, like the magic-lantern, always gives 

 inverted image-. Most commonly this causes no inconvenience, 

 for one can invert the object ; but there are cases in which this 

 cannot be done, and the only resource is to rectify the image. 

 To obtain this result, M. Duboscq (Journal de Physique, Octo- 

 ber) has recently conceived the idea of receiving the rays which 

 would go to form the inverted image on a prism with total reflec- 

 tion. Suppose an isosceles rectangular prism, placed with hypo- 

 thenuse parallel to the optic axis of the lens by which the rays 

 from the object are made convergent, and so as to receive the 

 cone of rays on one side ; refracted in the prism, the rays reach 

 the hypothenuse at an angle greater than the limiting angle, are 

 totally reflected, and sent to the second side of the prism, where 

 they are refracted at the same angle as on entrance, and then 

 go to the screen, forming an image which corresponds in position 

 to the object. As it may be desired to rectify the image in some 

 other plane than the vertical, it is found advantageous to mount 

 the prism in a tube forming part of the projection apparatus, 

 and capable of being turned round the direction of the ray. 



In a recent memoir on the plasticity of solid substances 

 (Rev. Scient. xi. 1S79), Signor Marangoni, with reference to 

 Bottomley's experiment dividing ice with a wire, groups plastic 

 substances in two classes. Those of the first class can be cut in 

 two with a metallic wire like ice, and they can also be consider- 

 ably deformed. Such are plastic clay, fresh soap, camphor, 

 black pitch. Substances of the second group give two lamella; 

 on the two sides of the cutting wire, which then come out of the 

 slit, become notched and bend over, resembling leaves ; to this 

 class belong vegetable Japanese wax, dry Marseilles soap, tallow 

 and stearine, but above all, yellow wax and paraffin. t The 



occurrence of these phenomena depends largely on the diameter 

 of the wire and on the temperature. For yellow wax, wires of 

 J to 1 mm. diameter, for paraffin h to o - 9 mm. are necessary. 

 With the former, the leaves are formed between - 8° and 40", 

 with paraffin (melting at 43'5°) only up to 15°. To produce 

 the lamella:, different weights should be hung to the wire in 

 different cases. The lamella: are very similar to those separated 

 from rails when a locomotive with strong brake applied, goes 

 quickly down a steep incline. 



The forms produced in the phonograph by utterance of the 

 Italian alphabet are studied in a recent paper by Signor Fautrier 

 (Aid del Aten. Veil. [3], I., 1879). The vowels uttered in the A 

 note of the violin (435 vibrations) gave generally three-pointed 

 groups, presenting certain differences. With regard to the con- 

 sonants, it appeared that with the exception of /, in, n, and r, 

 which give characteristic impressions, they only modify the form 

 of the impression of the following vowel, and especially at its 

 limits. Signor Fautrier adds some general considerations, espe- 

 cially on the intensity of the " klangs " given by the phonograph, 

 and the theoretical significance of the apparatus. 



M. Gaston Plante, whose researches on voltaic electricity, 

 especially on the construction of secondary batteries and on the 

 phenomena of their discharge have been from time to time laid 

 before the readers of Nature, has just published the first instal- 

 ment towards a second volume. The forty pages or so of this 

 brochure treat of the effects obtained with M. Plante's rheostatic 

 machine. 



Dr. Konig, the well-known constructor of acoustical appa- 

 ratus has just completed a new instrument which promises to be 

 of great interest and importance. Dr. Kbnig has long main- 

 tained, in opposition to the theory of Helmholtz, that the 

 "combinational" or "difference " tones produced by the simul- 

 taneous sounding of two simple tones of different pitch are the 

 result of very rapid " beats." The new instrument, which has 

 not yet been seen outside M. Konig' s atllicr, is a kind of modified 

 syren which puts the question at issue to a direct and crucial 

 test. 



We learn that Prof. Silvanus Thompson is engaged upon a 

 monograph upon the subject of Binaural Audition, which will 

 embrace the whole existing literature of the subject. The work 

 will not be published before next spring. 



The magnets employed in Gower's form of the Bell telephone 

 are of unusual strength. It is stated that the [steel of which 

 these magnets are constructed is made from the iron of Alvarre, 

 which, though a particularly bad iron for most purposes, makes 

 a steel unsurpassed for magnetic apparatus. 



The phenomena which occur when the retina is struck by 

 intermittent coloured light (alternating with total darkness) have 

 been recently studied by Signor Cintolesi {.Inn. di Oflalmol., II. 

 and III., 1879). With a certain velocity of intermissions the 

 field of vision appeared at first still and regular in the colour of 

 the active light. The state is gradually changed, and, e.g., red 

 passes by orange, yellow, and green, into a saturated blue-green, 

 after which there is a return by the same colours to red, and so 

 on in periodic change. This phenomenon of a periodic change 

 with the complementary colour the author also describes in the 

 cases of green and blue. The velocity of intermissions must 

 reach O'll sec. for red, 0-14 for green, and C15 for blue light. 

 In his theoretical views Signor Cintolesi has recourse partly to 

 the Young- Helmholtz hypothesis, partly to Plateau's oscillation 

 theory, and partly also to the photo-chemical properties of the 

 retina. 



It has been noted recently by M. Jannetaz that, if a fine 

 needle be turned round on a cleavage plate of gypsum (I mm. to 

 2 mm. thick) so as to produce a small hole, and then be gently 

 pressed into the plate, a separation occurs, surrounded by New- 

 ton's colour-rings, and having the form of an ellipse. The major 

 axis of this ellipse makes an angle of 49° with the fibrous frac- 

 ture, and its length is to that of the minor axis as 1-247 to '■ 

 This ellipse has the same orientation and relative size as that of 

 the propagation of heat in gypsum. Further, the larger axis 

 corresponds with the direction of greatest resistance to bending, 

 and the greatest elasticity. 



Edison's new electromotor, with which he proposes to drive 

 sewing-machines, watchmakers' lathes, and other light machi- 

 nery, has an armature resembling that of a Siemens dynamo- 

 electric generator, but placed longitudinally between the -limbs 



