tl CONTENTS OF VOL. XXXI. — THIRD SERIES. 



Page 

 Mr. J. J. Sylvester on the Equation in Numbers Ax^+By^ + Cz^ 



s^Dxyz, and its associate system of Equations (continued) . . 293 

 Mr. R. Taylor on the Invention and First Introduction of Mr. 



KcEnig's Printing Machine 297 



Proceedings of the Cambridge Philosophical Society 301 



On the Artificial Production of Minerals, and especially of Pre- 

 cious Stones 311 



Analysis of Kupfemickel 314 



On the Dehydration of Monohydrated Sulphuric Acid 314 



Observations on Silica, by M. Doveri 315 



On Nitric Mannite, by M. Sobrero 316 



On the Extraction of Silver, by MM. Malaguti and Durocher 317 



Vanadiate of Lead and Copper 319 



Meteorological Observations for August 1847 319 



Table 320 



NUMBER CCIX.— NOVEMBER. 



Prof. M. A. De la Rive's Researches on the Voltaic Arc, and 

 on the influence which Magnetism exerts both on this Arc 

 and on bodies transmitting interrupted Electric Currents . . 321 



Mr. T. Richardson's Analyses of the Ashes of Rough Brown 

 Sugar and Molasses 336 



Letter from Prof. Loomis of the New York University to Lieut.- 

 Colonel Sabine, Foreign Secretary of the Royal Society, on the 

 determination of differences of Longitude made in the United 

 States by means of the Electric Telegraph, and on projected 

 observations for investigating the Laws of the gi-eat North 

 American Storms 338 



The Rev. B. Bronwin on the Algebraic Equation of the Fifth 

 Degree 341 



Letter from Capt. J. H. Lefroy, R.A., Director of the Mag- 

 netic Observatory of Toronto in Canada, to Lieut. -Colonel 

 Sabine, R.A., on a great Magnetic Disturbance on the 24th 

 of September 1847 346 



Dr. H. Kolbe on the Decomposition of Valerianic Acid by the 

 Voltaic Current 348 



Mr. R. Adie's Account of Experiments with Galvanic Couples 

 immersed in pure water and in oxygenated water 360 



Dr. R. Hare on certain Improvements in the Construction and 

 Supply of the Hydro-Oxygen Blowpipe, by which Platinum 

 may be fused in the large way , 356 



Dr. J. W. Griffith on the Composition of the Bile of the Sheep 366 



The Rev. J. Slatter's Notice respecting the Meteor of Septem- 

 ber 25, 1846 368 



Mr. J. Glaisher on the Aurora Borealis, as it was seen on Sun- 

 day evening, October 24, 1847, at Blackheath 369 



