74 Scientific Intelligence. 
lar structure of benzol, C,H, According to the well known 
theory of Kekulé the six carbon atoms form a ring and are united 
by three single and three double bonds; but according to the 
theory of Ladenburg, the bonds in this structure are all single, 
each carbon atom being united with two of the other carbon 
atoms of the ring. The principles. deviloped by Bruhl give him 
a new test of the theories i in question since the molecular Sage 
nsity 
result which very closely agrees with the liecer 0 of the two 
values, Bruhl concludes that the generally She i sere of 
rie OOske 
8. Chemical Energy and Eilectromotive inseecd of different gn 
vanic elements,— THOMSEN rev ork upon this subject 
and makes a new and pera ah detaraination of he chemical energy 
and the electromotive force of a Daniells cell. According to his 
later measurements, the total devlopment of heat by galvanic 
means in all parts of the Daniells element amounts to 50292 units 
the chemical processes in the cell gives 50130 units. The differ- 
ence between 50292 and 50130 is so small that Thomsen concludes 
that the total chemical energy of a Danielle cell 3 is converted into 
electricity and the development of heat in yn A868 is the equiv- 
alent of the chemical energy developed by the cell. Other forms 
of cells are then ORE A from this point of view and the same 
conclusion is reached in the case of zine-cadmium elements and 
chloride of silver elem or in general wherever the metallic 
surface of the negative slastende is not changed by the nrgageye a: 
process.—Ann. der Physik und Chemie, No. 10, 1880, p. 2 
9. Spectra ds - compound of Carbon with Hydrogen “aie 
Nitrogen.—Professors Liveine an EWAR used in their experi- 
ments a PeMontene dyaueasalediae machine which oigeceve the 
voltaic are in the different gases they experimented u I . 
wee that the indigo, violet and ultra violet bands characteristic 
the flame of cyanogen are conspicous in the are taken in an 
in the — of cyanogen and hydrocyanie acid, but are not seen 
in those of hydrocarbons, enteks oxide, or carbon disulphide. 
The authions therefore conclude that they belong to cyanogen, and 
support this conclusion by reference to various facts. Their 
experiments on the spectrum of carbon are at variance with those 
of Lockyer on the same subject. They state that the evidence that 
carbon uncombined can take the state of vapor at the tempera 
