3(>0 Proceedings of the British Association, 



girding Its position. Its particular site had been described by an- 

 cient historians as on an island in the Nile, evidently formed of the 

 mud of that river ; and that it had been protected from inundations 

 by various extensive works erected by its kings. When its splen- 

 dour decayed, these works went out of repair, and hastened the 

 ruin of the city, which strewed with its fragments the place on 

 which it had stood. Finally, it was submerged under drifted sand, 

 and its true position became a problem to modern travellers. Of 

 late, however, the site has been determined by the French, who, in 

 one of their exploring expeditions, had examined the stratification 

 of the place supposed to be Memphis, and they ascertained the spot 

 by the succession of drifted sand, ruins, and mud. Its latitude they 



fixed at 29° 20' N. and longitude at 31° 30' E. from Greenwich 



JVIr Murchison spoke of the great value of geographical papers to the 

 geologist, and of the one just read, as an excellent example of this 

 kind. — Dr Buckland took this opportunity of mentioning the esta- 

 blishment of Mr Van der Maelen, at Brussels. That gentleman had 

 devoted, in the most praiseworthy manner, his time and fortune to 

 the advancement of science, by making large geographical and geo- 

 logical collections, for the purpose of diifusion over the world, by 

 means of exchange with societies or individuals. Dr Buckland ad- 

 vocated such a mode of obtaining maps and specimens to the dif- 

 ferent provincial societies of the United Kingdom. 



The next paper was on the change in the chemical character of 

 minerals induced by galvanism. Mr Fox mentioned the fact, long 

 known to miners, of metalliferous veins intersecting different rocks 

 containing ore in some of these rocks, and being nearly barren or 

 entirely so in others. This circumstance suggested the idea of 

 some definite cause ; and his experiments on the electro-magnetic 

 conditio!! of metalliferous veins, and also on the electric conditions 

 of various ores to each other, seem to have supplied an answer, in- 

 asmuch as it was thus proved that electro-magnetism was in a state 

 of great activity under the earth's surface, and that it was inde- 

 pendent of mere local action between the plates of copper and the 

 ore with which they were in contact, by the occasional substitution 

 of plates of zinc for those of copper, producing no change in the direc- 

 tion of the voltaic currents. He also referred to other experiments, 

 in which two different varieties of copper ore, with water taken 

 from the same mine, as the only exciting fluid, produced consider- 

 able voltaic action. The various kinds of saline matter which he 



