-'4 



NA TURE 



[June 27, 1895 



The crj'Stalsofthis secondar)- fonnation are not often distinctly 

 discernible in smaller masses of metallic iron, such as rolled rods, 

 plates, or sheets, as these in the course of manufacture rapidly 

 cool, and are frequently manipulated during the finishing pro- 

 cesses at temperatures below the crystallising point of wrought 

 iron (740° C). 



The microscopical examinations were made on carefully pre- 

 |)ared and polished samples, etched in nitric acid (i i«rt HNO3, 

 sp. gr. I '20, and 49 jxirts water), and by the use of high micro- 

 scopical powers (J-inch to ^^j-inch, and other ojectives); The 

 drawings were accurately made with the camera lucida. In each 

 observation the etching was prolonged, under constant ob- 

 servation with lenses, a suitable time to develop the accurate 

 structure of the metal. 



June 13. — "On the New Gas obtained from Uraninite." 

 Fourth Note. By J. Norman Lockyer, C.B., F.R.S. 



Continued exjierimenis on the gases obtained by heating the 

 minerals brc^gerite and euxenite in vatuo have revealed the 

 presence in the spectrum of an important line in the infra-red. 

 By comparisons with the solar spectrum in the first order grating 

 spectrum, the wave-length of the line has been approximately 



(2) Contrariwise, when we are dealing with a known com 

 pound gas : at the lowest tension we may get the complete 

 spectrum of the compound without any trace of its constituents, 

 and we may then, by increasing the tension, gradually bring in 

 the lines of the constituents until, when complete dissocia- 

 tion is finally reached, the spectrum of the compound itself 

 disappears. 



Working on these lines, the spectrum of the spark at at- 

 mospheric pressure, passing through the gas, or gases, distilled 

 from briiggcrite, has been studied with reference to the special 

 lines C (hydrogen), Dj, 667, and 447. 



The first result is that all the lines do not vary equally, as they 

 should do if we were dealing with a simple gas. 



The second result is that at the lowest tension 667 is re- 

 latively more brilliant than the other lines : on incre.-ising the 

 tension, C and 1)3 considerably increase their brilliancy, 667 

 relatively and absolutely becoming more feeble ; while 447, 

 seen easily as a narrow line at low tension, is almost broadened 

 out into invisibility as the tension is increased in some of the 

 tubes, or is greatly brightened as well as broadened in others 

 (Fig- !)• 



Fig. 1.— Diagram showing changes in intensities of lines brought about by var>'ing the tension of the spark, 

 (i) Without air-break. (2) With air-brcik. 



determined as 7065. There can be little doubt, from the 

 observations which have lieen made, that this new line is 

 coincident with a chromospheric line which occurs in ^'oung's 

 ILst, having a frequency of 100, and of which the wave-length 

 on Rowland's scale is statc-d to be 7o65"5. 



It follows therefore that, besides the hydrogen lines, all three 

 chromospheric lines in Young's list which have a frequency of 

 100 have now been recorded in the spectra of the new gas or 

 gases obtained from minerals by the distillation method. 



These are as follows : — 



7065-5 



5875-98 

 4471-8 



The wave-lengths of the lines are in Rowland's scale, as given 

 in Scheiner's "Astronomical Spectroscopy."' In a partial 



The above observations were made with a battery of five Grove 

 cells ; the reduction of cells from 5 to 2 made no dificrence in 

 the phenomena except in reducing their brilliancy. 



Reasoning from the above observations, it seems evident that 

 the effect of the higher tension is to break u|) a coni|x<und, or 

 compounds, of which C, Dj, and 447 represent constituent 

 elements ; while, at the same time, it would appear that 667 

 represents a line of some compound which is simultaneously 

 dissociated. 



The unequal behaviour of the lines has been fiirther noted in 

 another experiment, in which the products of distiJj.Ttion of hrog- 

 gerite were observed in a vacuum tube and jihotographed at 

 various stages. After the first heating, Dj and 4471 were seen 

 bright, before any lines other than those of carbon and hydrogen 

 made their appearance. With continued heating, 667, 5016, and 

 492 also appeared, although there was no notable increase of 



D, 



447. 



3876. 



654. 



667. 



Fic. 



49EJ0I 

 50* 

 Di.lgram showing order in which lines appcMr in spectrum of vacuum tube when brtiKneritc is heated. 



revision of his chromospheric list, Prof. Young gives the corona 

 line 53'6'79 ^^ "'''o having a frequency of 100 in the chromo- 

 sphere, but, up to the present, this line has not been an)ong 

 those obtained in the laljoratory. 



" On the New Gas obtained from Uraninite." Fifth Note. By 

 J. Norman Lockyer, C.B., F.R.S. 



In a former communication I |x>inlcd out the siwctroscopic 

 evidence, furnished by the isolation of lines in certain miner.ils, 

 which indicates that the complete siiectrum obtained when brrig- 

 gcritc is submitted to the distillation melhoti is prcxluced by a 

 mixture of g.ases. 



In order to test this view, I have recently made some obscr\a- 

 tion.s, \tmxA on the following considerations : — 



<I) In a simple gas like hydrogen, when the tension of the 

 electric current given by an induction coil is increased, by insert- 

 ing fir' - ■ - — ' •' , .,,1 air-break into the circuit, the efiecl is 

 •" inc- uid l.re.idth of all Ihe lines, the brilliancy 



AnAXiK. ,, „ '--t when the longest air-break is Used. 



' Froil's translation, p. 1B4. 



NO. 1339, VOL. 52] 



still further heating introduced 

 the following 



brightness in the yellow line ; 

 additional lines 5048 and 6347. 



These changes are represented graphically 

 diagram (Fig. 2). 



It was recorded further that the yellow line was at times 

 dimmed, while Ihe other lines were brightened. 



" On the Origin of the Triradiatc Spicules of Leucosolenia." 

 By IC. A. Minchin. 



Chemical Society, June 6.— Mr. A. Vernon llarcourl, 

 I'rcsiilenl, in llic 1 hair. — The following papers were read : — The 

 molecular refractions of dissolved salts and acids, by J. II. 

 Gladstone and W. Ililibert. The authors show that in many 

 cases when a pure sulistance dissolves in water, an alteration of 

 its specific refractive energy txrcurs. — A com|)arison of some 

 properties of acetic acid and its chloro- and bromo-derivatives, 

 liy .S. U. I'ickering. A number of thermal and other physical 

 proiierties of acetic acid, and its inonochloro- and monobromo- 

 derivatives have been (plant ilalively examined and compared ; 

 four distinct crystalline modifications of monochlor.-icelic acid 



