Proceedings of the British Association. 875 



slate was studded with crystals of arragonite, while the limestone 

 part was covered with crystals of calcareous spar, he subjected por- 

 tions of each of these substances in water, to long continued galvanic 

 action (ten days action,) and obtained from the slate crystals of arra- 

 gonite, from the limestone crystals of calcareous spar. In order to 

 ascertain if light had any influence in the process, he tried it again 

 in a dark cellar, and produced similar crystals in six days, with one 

 fourth of the whole voltaic power. He had repeated the experi- 

 ments a hundred times, and always with the same results. He was 

 fully convinced that it was possible to make even diamonds, and 

 that at no distant period every kind of mineral would be formed by 

 the ingenuity of man. By variations of his experiments he had ob- 

 tained crystallized quartz, the blue and green carbonates of copper, 

 chrysocolla, phosphate of copper, arseniate of copper, acicular car- 

 bonate of lead, sulphate of lead, sulphuret of iron, white antimony, 

 and many other minerals. 



Prof. Phillips then gave an interesting description of a bed of 

 magnesian limestone, which exists near Manchester. 



Evening Meeting. — Mr. Murchison exhibited a map of England, 

 colored to represent some phenomena of physical geography, and 

 for the purpose of answering a question proposed by the Association. 

 On a former evening Mr. Phillips had given an account of the boul- 

 der stones found in the north of England, and which had been traced 

 even as far as Worcestershire. Mr. Murchison, in his researches in 

 Wales and the neighboring counties, had not observed these carried 

 to the country bounded by the Severn, nor had he observed any of 

 the Silurian gravel carried to the central parts of England. From 

 this he concluded that Siluria must have been formed subsequently 

 to this central part, which might have been an island or part of the 

 continent. In this country of Siluria he had found the deposits of 

 gravel perfectly local ; nor could he perceive in this gravel any re- 

 cent shells ; on the borders of the South Wales Coal Basin were 

 marks of diluvial action — fragments of coal strata being thrown off 

 as from a centre. Another proof of the newer elevation of this part 

 of Britain, are the marks of large lacustrine expanses at recent peri- 

 ods. Out of this tract not only do we observe the boulders of granite 

 extending from north to south, but we find fragments of recent ma- 

 rine shells in the diluvium of Lancashire, Cheshire, Salop, and part 

 of Stafford, all diminishing as we approach the Severn. But he 

 was of opinion that these boulders could not have been so diffused 



