CHEMISTRY. 409 



which is an exampleof a closed chain of niue links. Further researches 

 led the author to the discovery of a body having the following consti- 

 tution: 



H2 H2 Ho H, H2 H2 



— (J — (J — S — (J — C — c 



I I 



s C C C s 



H2 H. H2 



which is the first example of a closed cliain of twelve links. These 

 bodies are quite unstable, as indeed might be anticipated from their 

 complex structure. (Naturwiss. Ruudschau, i, 2, 1886.) 



Products of the Manufacture of Gas from Petroleum, by Henry E. Arm- 

 strong and A. K. Miller.— This paper gives results of an investigation 

 which the authors have conducted during several years, on the decom- 

 position and genesis of hydrocarbons at high temperatures; their main 

 object has been to throw light on the nature of the changes resulting 

 from the decomposition of petroleum hydrocarbons at high temperatures. 

 The authors have thus far recognized among the products of the manu- 

 facture of oil-gas the following hydrocarbons : 



(fl) Paraffines, only in traces. 



(h) Pseudolefines, or saturated hydrocarbons of the series CnH2n, such 

 as occur in Russian petroleum; present in relatively small amount. 



(e) defines, viz, ethylene, propylene, normal amylene, hexylene, and 

 heptylene; higher homologues being absent. 



{d) Pseudacetylenes, viz, crotouylene (dimethylenethane) and iso 

 allylethylene. 



(e) Benzenoid hydrocarbons, viz, benzene, toluene, the three isomeric 

 dimethylbenzenes, the two trimethylbenzenes (pseudocumene and mesi- 

 tylene), and naphthalene. (J. Chem. Soc. [London], 3886, p. 74.) 



Some Organic Substances of High Eefractive Poicer, by H. G. Madan. — 

 The author finds that nai)hthyl-phenyl-ketone has a refractive index of 

 1.6G6, which is fiven higher than that of carbon disulphide (1.63). Its 

 dispersive power is almost exactly that of carbon disulphide. 



Metaciunaraene has a refractive index of 1.593; monobromonaphtha- 

 lene has a refractive index of 1.662, and the author thinks it may prove 

 a valuable substitute for carbon disulphide for filling prisms, as it is 

 much less volatile and inflammable. Mr. Madan mentions as a great 

 desideratum a substance having all the excellent qualities of Canada 

 balsam — colorless, neutral, permanent in the air, becoming fluid when 

 moderately heated, but hard and tough when cold, and with a refractive 

 index of at least 1.66. Such a substance would be invaluable for mount- 

 ing microscopic objects. (Phil. Mag. [5], xxi, 245.) 



A Convenient Method of Preparing Organic Compounds of Fluorine, by 

 O. Wallach. — The author finds that organic bodies containing fluorine 



