170 Profs. Liveing and Dewar on the Spectral Lines 



mixing vapour of ferric chloride with the hydrogen burnt in 

 an oxy hydrogen-jet, obtained a number of the lines of iron. 

 These form three groups — one below D, one. near E, and one 

 near G. The last two groups have a general correspondence 

 with the lines developed in the explosions in the visible part 

 of the spectrum ; but exact identification is not possible with 

 his figure. Of other metals he seems also to have found the 

 same lines in the oxyhydrogen-jet which we have seen in the 

 explosions, but with additional lines in several cases. Thus 

 he found three zinc and as many cadmium lines, two of 

 mercury, four of copper, and so on. 



Gouy (C.R. 1877, p. 232) has observed in the inner green 

 cone of a modified Bunsen burner fed with gas mixed with 

 spray of iron-salts, four green lines of iron which we did not 

 find in the flash. He saw two of the blue lines, but not the 

 other lines which we have noticed. In like manner with 

 cobalt, he observed two feeble blue rays which we did not 

 see in the explosions ; also one zinc, one cadmium, and one 

 silver line which we did not see ; and he did not notice the 

 green copper line which we always have seen in the ex- 

 plosions. In other cases he has noticed the same lines that 

 we have noticed. 



Comparing the spectrum of the explosions with that of 

 iron wire burnt in a jet of coal-gas fed with oxygen, they 

 may be called identical. We find in them generally the same 

 lines and the same relative strengths of the lines. For in- 

 stance, in the explosion -spectrum the strength of the groups 

 of lines on either side of M and the line at wave-length 3859*2 

 is decidedly greater as compared with the other lines than it 

 is in the arc-spectrum of iron. It is the same in that of iron 

 burnt as above mentioned. T, however, comes out more 

 strongly in the last-mentioned spectrum than in the ex- 

 plosions. 



German-silver wire burnt in the coal-gas and oxygen jet 

 gave the same nickel and copper lines as were developed in 

 the explosions. Silver wire gave in the same jet the two 

 silver lines near P, but no channelled spectrum. Spray of 

 cobalt chloride gave also the same lines as in the explosions, 

 with a few additional; while spray of manganese chloride 

 gave the strong manganese triplet at wave-length about 2800, 

 more refrangible than anything observed in the explosions, 

 besides the usual violet tripletc 



On the whole the spectra produced by the jet of coal-gas 

 and oxygen are very similar to those of the explosions as far 

 as the metallic lines go ; they exhibit a few more lines, or it 

 may be these are more easily observed, 



