103 



density 1*320. The bromine compounds, treated successively with 

 alcoholic potash and sodium, undergo a curious decomposition, the 

 original hydrocarbons, from which they were derived, being regene- 

 rated. The brominated oil from the naphtha, boiling between 71 

 and 77, affords hexylene boiling at 71, and the oil from the next 

 homologue distill ing bet ween 82 and 88, yields heptylene boiling at 

 99. The annexed Table illustrates some of their physical properties. 

 Physical Properties of Hexylene and Heptylene from Boghead 



Naphtha. 



VI. " On the Electrical Nature of the Power possessed by the 

 Actinise of our Shores." By ROBERT M'DONNELL, M.D., 

 M.R.I.A., Lecturer on Anatomy and Physiology in the 

 Carmichael School of Medicine, Dublin. Communicated 

 by WILLIAM BOWMAN, F.R.S., Surgeon to King's College 

 Hospital and the Royal London Ophthalmic Hospital. 

 Received November 30, 1857. 



After referring to the well-known phenomena manifested by elec- 

 trical fishes, and to alleged instances of numbing effects, but of doubt- 

 ful electrical nature, produced on the naked hand by the contact of 

 certain marine Invertebrata, the author describes his own observa- 

 tions and experiments with the Actinia as follows : 



Suppose that into a vessel containing some actiniae well expanded, 

 and apparently on the look-out for food, some of the tadpoles of the 

 common frog be introduced, these little creatures do riot, like many 

 freshwater fishes of about the same dimensions, immediately die; 

 on the contrary, the salt water seems to stimulate their activity, they 

 become very lively and swim about with vivacity. One of them may 

 not unfrequently be observed to make its way among the tentacles of 



