vi CONTENTS OF VOL. III. — FOURTH SERIES. 



NUMBER XIX.— MAY. 



Page 

 Dr. Tyndall's Reports on the Progress of the Physical Sciences. 



(With a Plate.) 321 



Dr. Kohlrausch on the Electroscopic Properties of the 



Voltaic Circuit 321 



Prof. Challis on a Mathematical Theory of M. Foucault's Pen- 

 dulum Experiment ""1 



Air. M. Donovan on the supposed Identity of the Agent con- 

 cerned in the Phenomena of ordinary Electricity, Voltaic 

 Electricity, Electro - magnetism, Magneto - electricity, and 



Thermo-electricity (continued) 335 



Prof. Ragona-Scina on the Longitudinal Lines of the Solar 



Spectrum. (With a Plate.) 347 



Mr. W. ^pottiswoode on a Problem in Combinatorial Analysis 349 

 Dr. Schunck on Rubian and its Products of Decomposition 



(concluded) 354 



Sir W. R. Hamilton on Continued Fractions in Quaternions 371 

 Dr. Griffith on the Triple or Ammonio-magnesian Phosphates 



occurring in the Urine and other Animal Fluids 373 



Mr. J. J. Sylvester on a remarkable Theorem in the Theory of 



Equal Roots and Multiple Points 375 



Prof. Miller on a new Locality of Phenakite 378 



Proceedings of the Royal Society 379 



On the Compound Ammonias, and the Bodies of the Cacodyle 



Series, by T. S. Hunt 392 



On the Invention of the Stereoscope, by James Elliot, Esq.. . 397 

 On the Artificial Production of Crystallized Tungstate of Lime, 



by N. S. Manross 397 



On the Green Colouring Matter of Plants, and on the Red Matter 



of the Blood, by F. Verdeil 398 



Equivalent of Phosphorus, by Prof. Schrotter 399 



Production of Cyanide of Potassium, by M. Rieken 399 



Meteorological Observations for March 1852 399 



Table 400 



NUMBER XX.— JUNE. 



Dr. Faraday on the Physical Character of the Lines of Magnetic 

 Force. (With a Plate.) 401 



Dr. Lamont on the Ten-year Period which exhibits itself in the 

 Diurnal Motion of the Magnetic Needle 428 



Mr. W. R. Grove on a Mode of reviving Dormant Impressions 

 on the Retina 435 



Mr. J. Cockle on Algebraic Transformation, on Quadruple 

 Algebra, and on the Theory of Equations 436 



Prof. De Morgan on the Authorship of the Account of the Com- 

 mercium Epistolicum, published in the Philosophical Transac- 

 tions 440 



