CHEMISTRY. 



133 



pared by dissolving onilino in an aqueous solu- 

 tion of trichloracetic ar'nl. 



The Constitution of the Elements. In a pa- 

 per read before the Royal Society, and also in 

 an article published in the " Nineteenth Cen- 

 tury," Professor J. N. Lockyer hag given an 

 account of the remarkable series of experiments 

 which in his opinion confirm the hypothesis 

 that the so-cnlled elements are really compound 

 bodies. This view, as is well known, was al- 

 ready held by many long before these inves- 

 tigations were begun ; indeed, the progress of 

 chemistry has proved several substances to be 

 compound that were previously ranked as ele- 

 ments, and left the list of simple bodies to con- 

 sist of such only as have hitherto resisted all 

 efforts at decomposition. It was believed that 

 the relations among the atomic numbers fur- 

 nish strong evidence of the composite nature of 

 many substances now classed as elementary, 

 and spectrum analysis has served greatly to 

 heighten this probability. Writing on the sub- 

 ject several years ago, Herbert Spencer took 

 the ground that the elements are not known 

 to be elementary ; that no intelligent chemist 

 holds them to be absolutely so ; and that many 

 concurrent considerations compel the inference 

 that they are compounded, and perhaps recom- 

 pounded, of a few and possibly a single primor- 

 dial constituent. For his views of the bearings 

 of spectroscopic research on this question, see ar- 

 ticle "Chemistry" in the "Annual Cyclopaedia " 

 for 1878. In a suggestive paper entitled " Evo- 

 lution and the Spectroscope," published in " The 

 Popular Science Monthly " for January, 1873, 

 Professor F. W. Clarke of Cincinnati expressed 

 similar views. He announced on spectroscopic 

 grounds the hypothesis that the evolution of 

 planets from nebula) has been accompanied by 

 an evolution of complex from simple forms of 

 matter, basing the idea upon the gradation of 

 chemical complexity in the celestial spectra. 



The important facts and fresh illustrations 

 brought forward by Professor Lockyer were 

 published in a summary of his paper before the 

 Royal Society, prepared by a chemist who 

 heard it for the London "Times," and from 

 this the subjoined extracts are taken : 



There are many facts and many trains of thought sug- 

 gested by solar and stellar physics which point to tine 

 hypothesis that the elements themselves, or at all events 

 si line of them, are compound bodies. Thus it would ap- 

 pear that the hotter a star the more simple is its spec- 

 trum ; for the brighest, and therefore probably the hot- 

 test stars, such as Sirius, furnish spectra showing only 

 very thick hydrogen lines and a few very thin metallic 

 lines, characteristic of elements of low atomic weight, 

 while the cooler stars, such as our sun, are shown by 

 their spectra to contain a much larger number of me- 

 tallic elements than stars such as Sirius, but no non- 

 metallic elements ; and the coolest stars furnish fluted 

 band-spectra characteristic of compounds of metallic 

 with non-metallic elements and of non-metallic ele- 

 ments. These facts appear to meet with a simple ex- 

 planation if it be supposed that as the temperature 

 increases the compounds are first broken up into their 

 constituent " elementSj" and that these " elements " 

 then undergo dissociation or decomposition into " ele- 

 ments " of lower atomic weight. Mr. Lockyer next 

 considers what will bo the difference in the spectro- 



Bcopic phenomena, supposing that A contains B an an 

 impurity and as a constituent. In both cane* A will 

 have a spectrum of its own. fi, however, If prenent M 

 an impurity, will merely add it linos according to the 

 amount present, as we have above explained : whereas, 

 if a constituent of A, it will add its lines according to the 

 extent to which A is decomposed and B is set at liberty ; 

 so that as the temperature increase* the spectrum or A 

 will tiide if A be a compound body, whereas it will not 

 liidu if A bo a true clement. Moreover, if A be a com- 

 pound body, the longest lines at one temperature will 

 not bo the longest at another. The paper chiefly deals 

 with a discussion from this point of view of the spec- 

 trum of calcium, iron, hydrogen, and lithium, as ob- 

 served at various temperatures : and it is shown that 

 precisely the kind of change which is to be expected 

 on the hypothesis of the non-elementary character of 

 the elements has been found to take place. Thus each 

 of the salts of calcium, so long as uie temperature is 

 below a certain point, has a definite spectrum of its 

 own ; but as the temperature is raised the spectrum 

 of the salt gradually dies out, and very fine lines due 

 to the metal appear in the blue and violet portions of 

 the spectrum. At the temperature of the electric arc 

 the line in the blue is of great intensity, the violet H 

 and K lines, as they are called, being still thin ; in the 

 sun the H and K lines are very thick ; and the line hi 

 the blue is of less intensity than either, and much 

 thinner than in the arc. Lastly. Dr. Muggins's mag- 

 nificent star photographs show that both the H and K 

 lines are present in the spectrum of a Aquilse, the lat- 

 ter being, however, only about half the breadth of the 

 former ; but that in the spectrum of a Lyrae and Sirius, 

 only the H line of calcium is present. Similar evi- 

 dence that these different lines may represent different 

 substances appears to be afforded by Professor Young's 

 spectroscopic observations of solar storms, he having 

 seen the II line injected into the chromosphere seven- 

 ty-five times, the JK line fifty times ; but the blue line, 

 which is the all-important line of calcium at the arc 

 temperature, was only injected thrice. In the spec- 

 trum of iron two sets of three lines occur in the region 

 between II and G, which are highly characteristic of 

 this metal. On comparing photographs of the solar 

 spectrum and of the spark taken between poles of iron, 

 the relative intensity of these triplets is seen to be ab- 

 solutely reversed ; uie lines barely visible in the spark- 

 photograph being among the most prominent in that 

 of the solar spectrum, while the triplet, which is promi- 

 nent hi the spark-photograph, is represented by lines 

 not half so thick in the solar spectrum. Professor 

 Young has observed during solar storms two very faint 

 lines in the iron spectrum near G injected thirty times 

 into the chromosphere, while one of the lines of the 

 triplet was only injected twice. These facts, Mr. Lock- 

 yer contends, at once meet with a simple explanation 

 if it be admitted that tiio lines are produced by the vi- 

 bration of several distinct molecules. 



The lithium spectrum exhibits a series of changes 

 with a rise of temperature precisely analogous to those 

 observed in the case of calcium. 



In discussing the hydrogen spectrum, Mr. Lockyer 

 adduces a number of most important and interesting 

 facts and speculations. It is pointed out that the most 

 refrangible line of hydrogen in the solar spectrum, A, is 

 only seen in laboratory experiments when a very high 

 temperature is employed, and that it was absent from 

 the solar protuberances during the eclipse of 1875. al- 

 though the other lines of hydrogen were photographed. 

 This line also is coincident with the strongest line of 

 indium, as already recorded by Thale"n, and may bo 

 photographed by volatilizing indium in the electric 

 arc ; whereas palladium charged with hydrogen fur- 

 nishes a photograph in which none of too hydrogen 

 lines are visible. By employing a very feeble spark 

 at a very low pressure, the F line of hydrogen in the 

 green is obtained without the blue and red lines which 

 are seen when a stronger spark is used, so that altera- 

 tions undoubtedly take place in the spectrum of hy- 

 drogen similar to those observed in the case of calcium. 

 In concluding this portion of his paper Mr. Lockyer 



