6i4 



NATURE 



{April 2 \, 1884 



a sensible deviation observed in the plumb-line between Milan 

 and Genoa, by E. G. Celoria. — On a hitherto neglected sidcus or 

 depression frequently occurring in the frontal bone of the human 

 skull between the boss and the temporal eminence, by Prof. G. 

 Zoja. 



March 20. — Obituary notice of the late Quintino Sella, by 

 Prof. T. Taramelli. — Memoir on Antonio A ngeloni Barbianiand 

 his literary productions, by E. B. Prina. — Biological notice of 

 Alosa vulgaris and Salmo carpio^ inhabiting the Italian and sub- 

 Alpine lakes, by Prof. P. Pavesi. — On the complete integers of 

 some classes of partially derived equations of any order with two 

 independent variants, by Prof. G. Pennacchietti. — Note on the 

 quantitative determination of alogenous bodies, by P. Ritter- 

 Zahony. — On the two human parasites Anguiilttla intestinalis 

 and A. stercoralis, by E. C. Golgi and A. Monti. — Absolute 

 values of the magnetic elements in Milan for the year 1S83, by 

 Dr. Giro Chistoni. 



Rivista Scuntifico-Industriale^ March 15. — Note on Wrob- 

 lewski's experimental studies on the liquidation of hydrogen. — 

 On the variation in the electric resistance of solid and pure me- 

 tallic, wires according to the teinperature, by Prof. Angelo Emo. 

 — On the pretended spontaneous combination of oxygen and 

 hydrogen without increase of temperature effected by the exclu- 

 sion of light, by L. Ricciardi. — On the migration of Fuligula 

 rufina and Erismalura kucocephala. Scop., by Dante Roster. 



Atti dclla R. Accadimia del Lined, March 2. — Report on 

 Alfredo Capelli's monograph on the composition of the groups of 

 substitutions, by S. Battaglini. — Report on Prof. G. Bellonci's 

 memoir on blastopore and the primitive line of the vertebrates, 

 by S. Todaro. — Remarks on a group of curves of the fourth 

 order, by Francesco Brioschi. — .\n experimental refutation of 

 the hypothesis that every double link between carbon and carbon 

 causes an increase of molecular refraction by a constant quantity, 

 by Rodolfo Nasini. — On the str.atification of the serpentine 

 rocks in the .A.pennines, part i., by Torquato Taramelli. — Note 

 on barometric hypsometry, by Aurelio Lugli. 



March l6. — Obituary notice of the late Quintino Sella, by S. 

 Maggiorani. — Meteorological observations at the Observatory of 

 the Campidoglio during the months of January and February. 



March 23. — On some unpublished and unknown works of 

 Bartolomeo Marliani, by Enrico Narducci. — A chemical analysis 

 of some brass and bronze objects found at the lacustrine station of 

 Benaco, in Lombardy, by Luigi Pigorini. — Report on the anti- 

 quities discovered in various parts of Italy during the month of 

 February 1884, by S. Fiorelli. — On barometric hypsometry, 

 second note, by S. Tacchini. — Absolute values of the m.agnetic 

 elements in Rome for the year 1883, by S. Tacchini. — On the 

 stratification of the serpentine rocks in the Apennines, part ii. , 

 by Torquato Taramelli. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, ,Vpril 3. — "Spectroscopic Studies on 

 Gaseous Explosions." By Professors Liveing and Dewar. 



Having occasion to observe the spectrum of the flash of a 

 mixture of hydrogen and oxygen fired in a Cavendish eudio- 

 meter, the authors were stnick by the briglitness, not only of the 

 ubiquitous yellow sodium line, but of the blue calcium line and 

 the orange and green bands of lime, as well as of other limes 

 which were not identified. The eudiometer being at first clean 

 and dry, the calcium must be derived either from the glass or 

 from some spray of the water over which the gases with which 

 the eudiometer was filled had been confined. It seemed incred- 

 ible that the momentary flash should detach and light up lime 

 from the glass, but subsequent observations have pointed to that 

 conclusion. Experiments were subsequently made on the flash 

 of the combining gases inclosed in an iron tube, half an inch in 

 diameter and about three feet long, closed at one end rwith a 

 plate of quartz, held in its place by a screw-cap and made tight 

 by leaden washers. 



The tube was placed so that its axis might be in line with the 

 axis of the collimator of a spectroscope, and the flash observed 

 as it travelled along the tube. 



It was seen at once that more lines made their appearance in 

 the iron tube than in the glass vessel, and one conspicuous line 

 in the green was identified in position with the E line of the 

 solar spectrum. Several other lines were identified with lines of 

 iron by comparison with an electric spark between iron electrodes. 



There could be no doubt that the flash in an iron tube gave 

 several of the spectral lines of iron. The authors supposed that 

 this must be due to particles of oxide shaken off the iron by the 

 explosion, and proceeded to try the effect of introducing various 

 substances in fine powder, and compounds, such as oxalates, 

 which would give fine powders by their decomposition in the heal 

 of the flame. Several interesting observations were made in this 

 way. When some lithium carbonate was introduced, not only 

 were the red, orange, and blue lines of lithium very brilliant, but 

 the green line hardly less so. After the lithium had once been 

 introduced into the tube, the lithium lines continued to makr 

 their appearance even after the tube had been repeatedly washed. 

 When the lithium had been freshly put in, the red line wa 

 observed to be much expanded, very much broader than the lin 

 given by lithium in a Bunsen burner reflected into the slit foi 

 comparison. The light was dazzling unless the slit was very 

 narrow ; and it was noticed that if the spark by which the ga> 

 was fired was at the distant end of the tube, so that the flame 

 travelled along the tube towards the slit, there was a reversal of 

 the red line ; a fine daric line was plainly visible in the middle of 

 the band. When the spark was at the end of the tube next the 

 slit, no reversal was, in general, seen. Later observations showed 

 that some other metallic lines might be reversed in this way, and 

 photographs taken of the reversals. These obsers'ations with the 

 eye on the reversal of the red lithium line were made with a 

 diffraction grating, and were repeated many times. They show 

 that there are gradations of temperature in the flame, and that 

 the front of the advancing wave of explosion is somewhat cooler 

 than the following part. The combination of the gases is not so 

 instantaneous that the maximum temperature is reached at once. 

 When some magnesia was put into the tube the continuous 

 spectrum was very bright, but the iron lines were still brighter. 

 No line which could be identified as due to magnesium was 

 observed with certainty ; there was only a doubtful appearance 

 of b. With sodium, 2Jotassiiim, and barium carbonates, only the 

 lines, usually seen when salts of those metals are introduced into a 

 flame were noticed ; but eye observations of this kind are ex- 

 tremely trying, on account of the suddenness of the flash and 

 the shortness of its duration. Thallium gave the usual green 

 line. 



Subsequently the interior of the tube was bored out so as to 

 present a smooth bright surface of iron, and the-iron lines which 

 were conspicuous in the flash were noted. 



For the purpose of identification the pointer in the eye-piece 

 was first placed on one of the strong iron lines given by the 

 electric discharge between iron electrodes, and then, the discharge 

 being stopped but the field sufficiently illuminated, the eye was 

 fixed steadily on the pointer while the gas in the tube was ex- 

 ploded. In this way it was not difficult to see whether any given 

 line was veiy bright in the flash. The lines thus identified were 

 those having the wave-lengths about 5455, 5446, 5403, 5396, 

 537'> 5327. 5269 (E), 5167 ((''4). These lines were all many 

 times observed in the way described, and as a rule were always 

 present in the flash. Lines with wave-lengths about 5139 and 

 4352 were seen, and may possibly have been due to iron, and 

 several more lines were seen occasionally, but were not so regu- 

 larly seen that they could be well identified. The lines \ 4923 

 and A 4919 were specially looked for, but neither of them could 

 be seen. A group of blue lines were noticed, and were after- 

 wards identified by photography, a method much less ti-ying than 

 observations by eye. To give intensity to the photographs ten 

 orStwelve flashes were usually taken in succession without any 

 shift of the instrument, so as to accumulate their effects in one 

 photograph. For ideptification the spark between iron electrodes 

 was also photographed, but with a shutter over the lower part of 

 the slit, so that the image of the spark should occupy only the 

 upper part of the field. 



Some sixty of the iron lines in the indigo, violet, and ultra- 

 violet were thus photographed. 



,Vs a rule no iron lines above O make their appearance ; in a 

 few plates T is visible, and it is possible that other lines may be 

 obscured by the water spectrum, which always comes out and 

 extends from near i to below R. Above T no line at all is 

 visible in any of the photographs,'though the spark lines come out 

 strongly enough, and several of the strongest groups of iron lines, 

 both of spark and arc lines, are in the region beyond T. 



Other experiments were made with explosions of carbonic oxide 

 and oxygen, and with coal-gas and oxygen. The explosions of 

 these gases were attended with much more continuous spectrum, 

 and the metallic lines were not always as well developed as they 



