ON WAVE-LENGTH TABLES OF THE SPECTRA OF THE ELEMENTS, 153 
SECOND XENON SPECTRUM—continued. 
| | Reduction to / 
Intensity, Liveing and Nace Oscillation 
Wave-length | and | Dewar Runge he 7 | Frequency | 
Character ae 1 in Vacuo | 
| vr | | 
243663 | 1 | 0-72 | 12-1 | 41023-2 
sooo | In A 35 45°7 
33°75 | 1 AW) eats 768 
32°87 : 1 Poe |. Sy Al 91°6 
29°11 | 1 | os, ebb SZ 
eons | Qn 3, || 122 | 492-8 
23°08 1 a5 ae 57°6 
22°28 3: ” ” 71:2 
21°36 1 0-71 FP, 86-9 
18°83 1 * Be 41330°1 
18°47 1 An = 36°2 
16°86 1 “5 me 63°8 
14°88 1 lie Satur | oe fy at 97°7 
+ Cf. Krypton IT. 2425-16 (1). 
The Study of Hydvo-Aromatic Substances.—Report of the Committee, 
consisting of Dr. EK. Divers (Chairman), Professor A. W. CROSSLEY 
(Secretary), Professor W. H. Perkin, Dr. M. O. Forster, and 
Dr. H. R. LE Sueur. 
Recent Work on Hydro-Aromatic Substances. 
By Professor A. W. Crosstey. 
Tue following is a summary of the work published on hydro-aromatic 
compounds since the preparation of the last report.' 
Petroleum.—The colourless and yellow distillates from naphtha give 
rotations? varying from +02 to +2°3 divisions of the Soleil- Ventzke 
scale in a tube 200 mm. long, the highest value being given by yellow 
cylinder oil from Baku naphtha. ‘ Benzine’ and petroleum from Grosny 
naphtha, also the yellow American cylinder oil ‘ Viscolite,’ exhibit dextro 
rotations. 
Hydrocarbons.—The hydrocarbon C,H ,, obtained by Wreden by the 
action of hydriodic acid on camphoric acid, has been regarded, from a 
consideration of its physical properties only, as 1 : 3-dimethylhexahydro- 
benzene. Balbiano and Angeloni* have now afforded chemical proof of 
this fact by a study of the oxidation products of the hydrocarbon. 
Another hydrocarbon of the formula C,H,, was prepared indirectly 
from camphoric acid, %.¢., by the reduction of laurolene (C,H,,) and iso- 
laurolene (C;H,,) by Zelinsky + and Lepeschkin in 1901, who considered, 
principally from a study of its physical properties, that it was the then 
unknown 1 : 1-dimethylhexahydrobenzene. This latter substance has 
recently been obtained from dimethyldihydroresorcin as a starting-point,” 
' Reports, 1904, p. 60. 2 Rakusin, J. Russ. Chem. Soc., 1904, 36, 554. 
8 Gaz. Chim. Ital., 1905, 35 (1), 144. 4 Annalen, 819, 311. 
5 Crossley and Renouf, Proc. C. 8. 1905, 20, 242, 
