VI CONTENTS OF VOL. XXXIV. — THIRD SERIES. 



NUMBER CCXXX.— MAY. 



Prof. H. Rose on the Isomeric Modifications of Phosphoric 



Acid , 321 



Sir W. R. Hamilton on Quaternions ; or on a New System of . 



Iraaginaries in Algebra (continued) 340 



Mr. W. H. Barlow on the Cause of the Diurnal Variations of 



the Magnetic Needle 344 



Mr. T. S. Davies's Note on Numerical Transformation 347 



Mr. G. G. Stokes on the Theory of Sound, in reply to Pro- 

 fessor Challis 348 



Dr. R. D. Thomson and Mr. E. T. Wood's Note on the Com- 

 position of Shea Butter and Chinese Vegetable Tallow .... 350 

 The Rev. J. Challis's Determination of the Velocity of Sound 



on the principles of Hydrodynamics 353 



Mr, J. Glaisher's Remarks on the Weather during the Quarter 



ending March 31, 1849 366 



The Rev. B. Bronwin on the Determination of the Coefficients 

 in any series of Sines and Cosines of Multiples of a variable 



angle from particular values of that series 374 



Mr. T. J. Herapath on some Combinations of Boracic Acid with 



Oxide of Lead 375 



Notices respecting New Books : — Mr. R. C. Taylor's Statistics 



of Coal 380 



Snowy Mountain in Eastern Africa 388 



On Mr. Struve's Mine Ventilator, by J. Richardson, C.E 389 



Analysis of Faujasite, by M. A. Damour 394 



Analysis of California Gold. 394 



On the Vanadiate of Lead and the Double Vanadiate of Lead 



and Copper, by M. Ignace Domeiko 395 



New Mineral from Brazil , 397 



Analysis of the Water of the Mediterranean on the Coast of 



France 398 



Impurity of Commercial Bromine 399 



Meteorological Observations for March 1849 399 



Table 400 



NUMBER CCXXXL— JUNE. 



The Astronomer Royal on a difficulty in the Problem of Sound 401 



Mr. J. Cockle on the Symbols of Algebra, and on the Theory of 

 Tessarines 406 



Mr. E. J. Lowe on Remarkable Solar Halos and Mock Suns 

 seen at the Observatory of Henry Lawson, Esq., F.R.S. &c., 

 Lansdown Crescent, Bath. (With a Plate.) 410 



Prof. J. R. Young on an Improvement in the Analysis of Equa- 

 tions , 413 



