326 REPORT—1899. 
Latterly the following substances have been examined with a like 
result : 
Typical Closed Chain Compounds which show no Absorption Bands, 
but transnut Continuous Spectra. 
CH,—CHy 
cog eo (,H,0-CH(N : CH-C,H,0), 
CH,—CH, Furfuramide 
Diketo-hexa-methylene 
ea aige ie HC———CH HC CH 
| | | || | | 
HC C:GOB ‘y. 2He C-COOH HC HC 
Nex orig NB 
Furfuraldehyde Pyromucic Acid Furfurane 
HC——— CH HC——_—CH 
| | | | 
HC CH Et CH 
Bisa ak 
Pyrrole Thiophene 
The absorption of the ultra-violet rays by solutions of some of these 
substances, and particularly thiophene, is very intense, but in no case is 
there any selective absorption. 
It is necessary now to refer back to a series of papers included under 
the heading ‘ Researches on the Relation between the Molecular Structure 
of Carbon Compounds and their Absorption Spectra. ’? 
On MOoLecuLAR AND INTRAMOLECULAR VIBRATIONS. 
In the ‘Chem. Soc. Trans.,’ vol. xxxix. p. 161, 1881, the spectra of 
condensed benzene nuclei were examined, such as are obtained from 
naphthalene, anthracene, and phenanthrene. The diagrams of the absorp- 
tion spectra of these substances were drawn to scale, and they show 
enormous differences in the intensity of the absorption bands in these 
different hydrocarbons as well as differences in the positions of the bands, 
For instance, six bands were measured in the spectrum of benzene, and 
four of these are visible when one part is diluted with 2,400 of alcohol ; 
then in naphthalene with a dilution of 1 in 100,000 parts, one in phenan- 
threne with 1 in 500,000 parts, and one in anthracene with 1 in 5,000,000 
parts, the thickness of the layer of liquid in each case being only 15 
millimetres. In February, 1881,*it was stated that the mean wave-length 
of the rays intercepted by ozone is 2,560 tenth-metres. From this the 
mean rate of vibration of the molecule of ozone can be calculated. When 
perfect absorption occurs, the molecule of the absorbing medium must be 
vibrating synchronously, and in the same plane with the ray absorbed, 
from which it follows, if the velocity of light be taken as 315,364,000 
metres per second (Fizeau), the mean rate of vibration per second of time of 
the molecule of ozone must amount to 1,231,000,000,000,000 vibrations. 
1 «The Ultra-violet Absorption Spectra of some Closed Chain Carbon Compounds,’ 
Trans. Chem. Soc. 1898, p. 598, W. N. Hartley and James J. Dobbie. 
2 Trans. Chem. Soc. 1881, W. N. Hartley. 
3 Trans, Chem, Soc, vol. xxxix. p, 60, ‘On the Absorption Spectrum of Ozone,’ 
Hartley. 
