Geology and Physical Geography. 367 



of green colour : the result of which was, that what was before 

 inharmonious in colour and grouping, at once resumed har- 

 mony in these respects, and became perfectly intelligible. 

 An analysis of the glass made by Professor Voelcker showed 

 the cause of change from ruby to green to have been due to 

 the fact that the antique ruby glass had derived its colour 

 from suboxide of copper, and that the tessellae had become 

 covered with carbonate of copper from a decomposition of 

 their sui*faces. 



On the " Phosphorescence of Potassium,*' by Mr W. Petrie. 



" On the presence of Fluorine in Blood and Milk," by Dr 

 G. Wilson. This communication is given in full, page 227. 



" On the presence of Carbonates in Blood," by Professor 

 G. J. Mulder, of Utrecht. — The intention of Professor Mulder 

 was to show experimentally that blood contains carbonic acid 

 not merely in solution, but also in chemical combination with 

 bases and organic substances, as globulin, albumen, &c. 



" On a compound of Iodine and Codeine," by T. Anderson, 

 M.D. — The compound of Iodine and Codeine which formed 

 the special subject of this communication is obtained by mix- 

 ing together alcoholic solutions of equal quantities of Codeine 

 and Iodine, and leaving the mixture to spontaneous evapora- 

 tion, when the new compound is deposited in crystals. The 

 compound is insoluble in water, sparingly soluble in cold 

 alcohol, but readily in boiling, and it is again deposited in 

 small triangular plates as the solution cools. Its crystalline 

 form has been determined by Professor Haidinger, of Vienna, 

 who finds it to belong to the doubly oblique system. The 

 crystals have a fine diamond lustre and a deep purple colour 

 by reflected, and ruby red by transmitted light. In powder 

 its colour is cinnamon brown. 



" On a direct method of separating Arsenious from Arsenic 

 Acid, and on its application to the estimation of Nitric Acid," 

 by Mr J. Stein. 



Section C. — Geology and Physical Geography. 

 Professor Ramsay read a paper on the position of the 

 black slates of the Menai Straits. 



Professor Nicol then read a translation of a communica- 



