M. A. J. Angstrom's Optical Researches. 337 



uuoxidizable metal were made use of, I had the two spheres thickly 

 gilt (with mercury gilding) and repeated the experiment with 

 carbonic acid. There was no alteration of these lines, which I 

 regard as belonging to the gas. The lines of the metal had, 

 however, been changed, but without becoming quite like those 

 observed in former instances with gold. A luminous band, broken 

 in the middle, showed itself in the oxygen spectrum three lines 

 higher, which corresponds to F in the air spectrum, without, 

 however, coinciding with one of the zinc lines. Besides this, 

 at 5 and E fine lines were observed. 



14. Binoocide of Nitrogen, NO 2 . — A mixture of sugar and 

 dilute sulphuric acid was heated, and the developed gas was 

 conducted, first through water, and then through the drying 

 bottle before mentioned. The spectrum of the gas showed a 

 union of the air and oxygen spectra, although by no means com- 

 plete. As, according to Berzelius, the electric spark decomposes 

 the nitric oxide into nitrogen and nitrous acid, or more probably 

 hyponitrous acid, the two lines y and S must belong to the 

 nitrogen. It is more difficult to explain the production of the 

 oxygen lines, if we do not assume that the nitrous acid is still 

 further decomposed. 



15. Hydrogen. — This gas was produced from zinc and sul- 

 phuric acid, being dried in the ordinary manner. The spectrum 

 is shown at H a and Hj in fig. 3. H s represents, in an approxi- 

 mate manner, the luminous intensity of the different parts of 

 the spectrum. Remarkable, in the case of hydrogen, are the 

 strongly luminous and wide lines at the red end of the spectrum 

 which, moreover, besides a feeble line in the vicinity of the' 

 former, contains only two bright portions, one at the limit of 

 blue and green, and the other in the extreme blue. 



In general the hydrogen spectrum bears a great resemblance 

 to that of the flame of alcohol, only the red lines must be con- 

 ceived to be moved nearer to the yellow light. The facility 

 with which hydrogen transmits electricity is remarkable. "When 

 the spheres were almost 2 inches asunder, the sparks passed 

 with the greatest ease. 



16. Carburet ted Hydrogen, CH. — This gas was developed from 

 alcohol and sulphuric acid, then conducted through a solution 

 of potash, and afterwards through the drying apparatus. The 

 spectrum was nearly the same as that obtained with hydrogen, 

 and for this reason I have not drawn it. It was however brighter, 

 particularly in the green, and also showed to the left of E, fig. 1, 

 a bright line, which I did not find in the hydrogen spectrum. 

 As the electric spark decomposes carburetted hydrogen into its 

 elements, this result is not to be wondered at, particularly as 

 coal exhibits no lines peculiar to itself in the spectrum. 



Phil. Mag. S. 4. Vol. 9. No. 60. May 1855. Z 



