358 Proceedings of the British Association. 



sulphuric acid of commerce, adding the acid gradually, the vessel 

 containing the mixture being kept in a frigorific preparation, so 

 as to prevent the heat evolved from exceeding 100°. The mu- 

 riate of ammonia is dissolved in soft water to saturation. The 

 zinc is not amalgamated, and the use of cast zinc is to be avoid- 

 ed. The platina is the thinnest foil that can be procured, but the 

 author found that box-wood, cut to the thickness of veneer, and 

 charred on each side superficially, might be substituted, and used 

 with equal advantage. The author stated that with a voltaic 

 combination consisting of half a fluid ounce of the acidulated 

 nitrate solution, one ounce of the saturated solution of muriate 

 of ammonia, a strip of platina foil three inches by two, surround- 

 ed by a piece of sheet zinc of equal surface, he had succeeded in 

 supporting a weight of two thousand pounds with an electro- 

 magnet of the horse-shoe form, measuring sixteen inches from 

 pole to pole, and three fourths of an inch in diameter, and that 

 the attractive force before contact was in proportion. 



The following papers were also communicated to the Section. 



On the Electrolyzing Power of a simple Voltaic Circle, by Prof. Schonbein. 



On the manufacture of Sulphuric Acid, by Win. Blyth. 



Account of the Mineralogical and Geological Museum of the Imperial Mining 

 Department of Vienna, by Prof. Haidinger. 



On some new oxides of certain of the metals of the Magnesian family, by Dr. 

 Lyon Playfair. 



Account of a simplified Apparatus, for applying Circular Polarization to Chem- 

 ical Inquiries, by Prof. Powell. 



On the electric origin of the Heat of Combustion, by J. P. Joule. 



On the causes of the irregularities of surface which are observable in certain 

 parts of the Magnesian Limestone formations of this country, by Dr. Daubeny. 



On the composition of the blood and bones of domestic animals, by Prof. Nasse 

 of Marburg. 



On the manufacture and purification of Coal Gas, by John Davies of Manchester. 



On the formation of Cyanuret of Potassium in a Blast Furnace, by Dr. C. Bro- 

 meis of Cassel. 



On a new product obtained from Coal Naphtha, by Mr. Leigh. 



On Kakodylic Acid, and the Sulphurets of Kakodyl, by Prof. Bunsen of Mar- 

 burg. 



On the compounds of Carbon and Iron, by Dr. C. Bromeis. 



Contributions to the history of the Magnesian Limestones, by Mr. Richardson. 



On a peculiar condition of Iron, by Prof. Schonbein. 



On a new method of analyzing Cast Iron and other metallic carburets, by Dr. 

 Ure. 



On the advantages and disadvantages of Hot Air, in effecting the combustion of 

 Coal, by Mr. Williams. 



On certain Thermometrical Researches, by Prof. Graham. 



On the composition and characters of Caryophyllin, by Dr. Lyon Playfair. 



