Proceedings of the British Assodatio7i. 53 



it was rare, and single crystals sold at £10 each. — Prof. Andrew 

 Buchanan related his method of separating, by filtration, the co- 

 agulable lymph from liquid human blood. — Dr. Clark, of Ahex- 

 deen, stated his mode of detecting minute portions of arsenic. — 

 Mr. McGregor read a paper containing experiments made by him 

 while resident in the Royal Infirmary of Glasgow, which showed 

 that the per centage of carbonic acid thrown off from the lungs 

 is greater in disease than in health. — A paper by Messrs. Redten- 

 bacher and Varrentrapp was read, on the constitution and products 

 of the distillation of fat bodies. — Prof. Bunsen stated his new 

 mode of estimating nitrogen in organic analysis. He introduces 

 the substance to be analyzed, after having mixed it with oxide 

 of copper, into a glass tube. A few slips of metallic copper are 

 then added, and the tube is fixed to Dobereiner's apparatus for 

 producing hydrogen. This gas is conducted through it until all 

 the atmospheric air is expelled, giving the tube at the same time, 

 a rotary motion, in order to dislodge any air which might be re- 

 tained between the particles of the oxide of copper. The tube 

 is now hermetically sealed, and introduced into an iron vessel, 

 filled with moist gypsum. Thus prepared it is introduced into 

 the common oven used for organic analysis, and surrounded with 

 red-hot coals. If the tube is of strong green glass, it never bursts. 

 When the combustion is completed, the tube is placed below a 

 graduated glass receiver standing over mercury, and the point cut 

 off. The gas, which had a pressure of several atmospheres, now 

 rushes into the jar. The carbonic acid is absorbed by a ball of 

 hydrated potash, which is introduced into it, and the remaining 

 gas must be nitrogen, for all the hydrogen must have been con- 

 verted into water by the oxygen of the oxide of copper. The 

 results obtained by this method agree with theory to the second 

 and often to the third decimal place. — Prof Penny gave an ac- 

 count of a new salt obtained from iodine and caustic soda, which 

 he names the sesquiodide of iodate of soda. — Prof. Johnston read 

 a paper on resins, containing the following results. 1. The resins 

 differ from each other in the quantity of oxygen they contain. 



2. Those in which the atoms of oxygen is the same, may vary 

 in the hydrogen, which is another cause of difference in properties. 



3. In all the resins hitherto analyzed, the number of atoms of car- 

 bon is constant. 4. The resins, as a natural family, may be rep- 

 resented by a general formula containing two variables. 5. The 



