NA TURE 



\yan. 21, 1875 



SCIENTIFIC SERIALS 



Poggaidorff'' s Annahti der Physik nnd Chemie, No. 10. — 

 This nui&ber contains several papers of great interest : the first 

 is by G. Quinclie, on electric currents resulting from the non- 

 simultaneous insertion of two mercury-electrodes into different 

 liquids. The author bases his experiments upon those of St. 

 Claire Deville and Troost, who found it probable that platinum 

 absorbs hydrogen or otlier gases when being heated in a gas or 

 alcohol flame, and then shows a different electric action towards 

 water end dilute acids from that of platinum that has not been 

 so heated. The paper contains a minute description of the 

 apparatus used and tables of the results obtained ; in an appendix 

 the author treats of the relation between capillary and electrical 

 phenomena, referring to G. Lippmann's paper (Pogg. Ann., vol. 

 149, p. 556), from whom he materially differs. — Experiments 

 made wiUi a magnetised copper wire, by Prof. Balfour Stewart 

 and Dr. A. Schuster. — On the chemical action of the solar 

 spectrum upon haloid salts of silver, by H. W. Vogel. Chloride, 

 bromide, and iodide of silver, are not only sensitive towards the 

 highly refrangible rays of the spectrum, but also towards the 

 less refrangible ones, although in a much smaller degree ; tlieir 

 sensitiveness does not only depend upon their optical power of 

 absorption of the respective rays, but also upon the absorption 

 power of other substances they may be mixed with. Coloured 

 substances which assist the photographic reduction process and 

 absorb certain spectral rays, highly increase the sensitiveness of 

 the silver salt towards the absorbed rays ; thus the sensitiveness 

 of silver salts for red, yellow, and green rays can be greatly aug- 

 mented. Certain colourless bodies are found to have a similar 

 action. The light reflected from pigments shows a very different 

 effect from that of spectral colours, on account of the varying 

 optical composition of artificial colours and their smaller inten- 

 sity. — On the question of velocity of magnetic action at dis- 

 tances, by H. Herwig ; investigations relating principally to ter- 

 restrial magnetism. It is found that this velocity is at least half a 

 million geographical miles (or about 2^ millions of English miles) 

 per second; in other words, that at any given spot on the surface 

 of the earth terrestrial magnetism becomes fully active in less 

 than the 300th part of a second. — On a modification of the mag- 

 neto-electric revolution experiment, by the same. — On compari- 

 son of electric machines, by Mr. Mascart. The author describes 

 experiments made to ascertain the actual quantity of electricity 

 produced by eleven different machines in a given time and under 

 the same conditions. — On the measuring of the electromotive 

 power of voltaic piles in absolute units, by A. Crova. — The fre- 

 quency of changes of colour in the scintillation of stars is gene- 

 rally related to the spectrum they show, by C. Montigny. Stars 

 that twinkle strongly show few spectral lines, while those with 

 little scuitillation have many bands and lines in their spectra. — 

 On the theory of organ-pipes, by H. Schneebeli. — Is the appli- 

 cation of the vis viva justified in the mechanical theory of heat? 

 by H. Fritsch. The author answers this question in the negative. — 

 On induction-effects in magnets of different hardness, by L. Kiilp. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, Jan. 7. — " Remarks on a New Map of the 

 Solar Spectrum," by J. Norman Lockyer, F.R.S. 



I beg permission to lay before the Royal Society a portion of 

 the new map of the solar spectrum, referred to in one of my 

 former communications. 



It consists of the portion between w. 1. 39 and 41. 



I have found it necessary, in order to include all the lines 

 visible in my photographs in such a manner that coincidences 

 may be clearly shown, to construct it on four times the (scale of 

 Angstrom's " Spectre-Normal." 



The spectra of the following elements have been photo- 

 graphed side by side with tlie solar spectrum, and the coinci- 

 dences shown : — 



Fe, Co, Ni, Mn, Ce, U, Cr, Ba, Sr, Ca, K, AI. 



The wave-lengths of new lines in the portion of this spectrum 

 at present completed have been obtained from curves of graphical 

 interpolation. Instead of the reading of a micrometer- scale, a 

 photographic print of the spectrum has been employed in the 

 construction of these curves, the wave-lengths of the principal 

 lines being taken from an unpublished map of the ultra-violet 

 region of the solar spectrum, a copy of which has been kindly 

 placed at my disposal by M. Cornu. The photograph of the 



solar spectrum, from the ultra-violet to beyond F, kindly given 

 to me by Mr. Rutlierford, has also proved of great service in the 

 present work, I have, in fact, up to the present time, only 

 been able to excel this photograph in the region about II. 1 



From the extreme difficulty of carrying on eye-observations 

 upon the portion of the spectrum now completed. Angstrom's 

 map is, of course, very incomplete about this region. The few 

 lines mapped differ slightly in some cases from the positions 

 assigned by Cornu ; but the wave-lengths given by the latter 

 observer generally fall hito the cuive without breaking its 

 symmetry, and these positions have therefore been adopted. The 

 advantage possessed by the photographic method over eye- 

 observation may be estimated from the following numerical 

 comparisons : — 



Region of specttum, 3900-4100. 



Number of lines in Angstrom's " Spectre-Normal" 39 



,, „ Angstrom's and Thalen's map of the 



violet part of the solar spectrum ... 183 



,, ,, Cornu's map , 205 



,, ,, New Map 1518 



It will serve further to illustrate the advantages of the photo- 

 grapliic method, to compare the number of lines in the spectra 

 of metals already observed with the number of lines of the same 

 metal given by Angstrom in the " Spectre-Normal." 

 Region of spectrum, 3900-4100. 

 Metal. Lines in new map. Lines in^Thaleli's map. 



Fe 71 19 



Mn i 53 12 



Co 47 — 



Ni ... ■ 17 ^ 



Ce 163 — 



U 18 — 



Cr 24 — 



Ba 7 — 



Sr S - 



Ca 7 6 ^ 



K 2 — 



Al 2 2 



Total 



416 Total ... 39 



The purification of the various metallic spectra has at present 

 been only partially effected ; but I have seen enough already to 

 convince me of the extreme] rigour with which the principle I 

 have ahe.idy announced may be applied, while at the same time 

 there aie evidences that tlie application of it may lead to some 

 results not anticipated in the first instance. 



My object in laying these maps before the Society, and pre- 

 senting this ad iiileiim report of progress, is to appeal to some 

 other man of science, if not in England, then m some other 

 country, to come forward to aid in the work, which it is impro- 

 bable that I, with my small observational means and limited 

 time, can carry to a termination. I reckon that, having regard 

 to routine solar work, it will require another year before the por- 

 tion from H to G is completely finished, e\'en for the metals the 

 spectra of which are shown in the maps now exhibited. When 

 this is done there will still remain outstanding all the ultra- 

 violet portion, the portion from G to F, both capable of being 

 photographed by short exposure, and the whole of the less 

 refrangible part, which Draper and Rutherford have both shown 

 can be reached^by long exposure with the present processes. 



I cannot but think, moreover, that when the light Which the 

 spectroscope has already thrown upon molecular aciion shall be 

 better known, and used as a basis for further inquiry, methods 

 of photography greatly exceeding the present one m rapidity, in 

 the less refrangible portion of the specuum, will be developed 

 and utilised in the research. 



The map is being drawn by my assistant, Mr. Raphael Mel- 

 dola (to whom my thanks are due for the skill and patience he 

 has brought to bear upon the work), in the first instance with 

 more especial reference to the positions, thicknesses, and indi- 

 viduahties of the lines ; the final revision will consbt of an abso- 

 lute intensity reproduction of the photographs. 



" On the Spectrum of Coggia's Comet," by WilUm Muggins, 

 D.C.L., LL.D., F.R.S. 



From his observations of five small comets in the years 1 866, 

 186S, and 1S71, the author had shown that a great part of the 

 light of those comets was emitted by the cometary matter ; and 

 further, that carbon, in some form, was probably present in 

 them. 



