SUPPLEMENTARY NOTES. 463 



ihe London Clay, moie than 25,000 specimens. The species I 

 have already determined exceed 500 in number, and I have no 

 doubt that several hundred more may be estimated at the true num- 

 ber in my collection. The late Mr. Crow informed me that he 

 was acquainted with between 6 and 700 species. None of these 

 fruits can be with certainty referred to any recent species, although 

 the approximation is in many instances very close. Palmaceous 

 fruits are abundant, and many other fruits agreeing not only in ex- 

 ternal form, but in internal structure with well known classes of 

 seed-vessels of the present period ; along with these there are some 

 which I have not as yet been able to refer to any known form of 

 fruit. Coniferous fruits are comparatively scarce, although the re- 

 mains of Coniferous branches are by no means uncommon. A 

 similar discrepancy exists as regards the Palms, stems of palma- 

 ceous structure being rarely found, although the species of fruits 

 of that order are numerous. The principal bulk of fossilized 

 woods found in the London Clay are decidedly Dicotiledonous, and 

 the great bulk of fossil fruits likewise. The internal structure of 

 both fruits and woods is preserved in a most perfect and beautiful 

 manner." 



P. 412. At a meeting of the British Association at Bristol, in 

 August, 1836, Mr. R. W. Fox submitted to the Geological Sec- 

 tion an experiment, showing that the native yellow copper, or bi- 

 sulphurel is convertible into the suJphitret of that metal by weak 

 voltaic action. His apparatus consisted of a trough divided into two 

 compartments or cells, by the intervention of a mass or wall of 

 moistened clay. In one of these cells he put a solution of sulphate 

 of copper, and a piece of the yellow bi-sulphuret of copper ; and in 

 the other cell, some water with a little sulphuric acid in it, or wa- 

 ter only, without acid, together with a piece of Zinc which was 

 connected with the copper pyrites in the other cell, by means of a 

 copper wire. 



This simple voltaic arrangement quickly changed the surface of 

 the copper ore from a yellow to a beautiful iridescent colour, after- 

 wards to a purple copper, and finally, in the course of a few days, 

 to the sulphuret, on which metallic copper was copiously deposited 

 in brilliant crystals. When this process was continued for some 



