Proceedings of the Royal Society. 201 



ances are exactly those which ought to be observed, if we suppose 

 chlorides and iodides to be dissolved as such in absolute alcohol, 

 and as muriates and hydriodates in water. In none of these cases 

 was chlorine or iodine produced, except at the positive pole in the 

 positive water, by a secondary action on the corresponding hydracid. 

 When etherial solutions of various substances, such as potash, 

 chromic acid, and metallic chlorides, are submitted to galvanic ac- 

 tion, there is no symptom of decomposition either of the solvent or 

 of the dissolved body. Thus no exception has yet been met with 

 to the general conclusion, " That when solutions of binary combina- 

 tions of elementary bodies in water, alcohol, or ether, are submit- 

 ted to voltaic agency, the dissolved substance is not decomposed 

 but only the solvent, if itself an electrolyte." A few cases, how- 

 ever, comprehended within the law still remain to be experiment- 

 ally investigated. 



Sir Charles Bell gave a Verbal Notice regarding the import- 

 ance of the Circulation in the Medulla Oblongata, and 

 the office of the Vertebral Artery. 

 April 3. — The Right Honourable Lord Gkeenock, Vice- 

 President, in the Chair. The following communications were 

 read: 



1. Geological Observations on Binny-Cragin West-Lothian, 

 by Charles Maclaren, Esq. 



Binny Crag in West Lothian is of compact greenstone, about half 

 a mile in length, and from twenty to one hundred and forty feet in 

 breadth. It extends south and north, and has a small ravine on its 

 west side, above which the highest part of the crag rises about two 

 hundred feet. Three phenomena connected with this crag are wor- 

 thy of observation. I . It has the character of a trap vein which has rup- 

 tured the strata in a fluid state. The dip of the sedimentary rocks on 

 its west side is to west-south-west, o.a the east side to the east, and 

 in both cases at a pretty high angle. We have here, therefore, evi- 

 dence of the strata having been ruptured, and a fissure formed ; and 

 we have the trap, the rupturing agent, placed on the fissure, and 

 occupying the anticlinal line, or axis of the upheaving movement. 

 According to the received hypothesis respecting the origin of trap, 

 we might expect this appearance to be common, and yet it is rather 

 rare. It forms the exception, while it ought apparently to be the 

 rule. 2. The trap Juts mingled tvith the shale, and affected its stnic- 

 ture in a very remarkable manner. It has enveloped portions of the 



