CONTENTS OF VOL. XXXVI. — THIRD SERIES. Vll 



Page 



Equivalent of Chromium, by M. Lefort 407 



Meteorological Observations for March 1850 407 



Table 408 



NUMBER CCXLV.— JUNE. 



M. Regqault on the Measurement of Temperatures by Thermo- 

 electric Currents. (With a Plate.) 409 



Mr. W. R. Birt on the Hail Storm of May 5, 1850, as observed 



at the Kew Observatory 420 



Prof. Wartmann's Eighth Memoir on Induction (^continued) . . 423 

 Prof. Donkin on the Geometrical Laws of the Motion of a Rigid 



System about a Fixed Point 427 



M. J. Plateau on a new and curious Application of the Per- 

 manence of Impressions on the Retina. (With a Plate.) . . 434 

 M. J. Plateau's Second Note upon some new and curious Ap- 

 plications of the Permanence of Impressions on the Retina. 



(With a Plate.) 436 



Prof. Locke on the Phantascope 453 



Captain Lefroy's Preliminary Report on the Observations of 

 the Aurora Borealis, made by the Non-commissioned Officers 

 of the Royal Artillery, at the various Guard-rooms in Canada 457 



Proceedings of the Royal Society 466 



Royal Astronomical Society 470 



On Brongniardite, a new Mineral, by M. A. Damour 477 



Action of Sulphate of Magnesia and Sulphate of Zinc, by M. 



SchaeufFele 479 



On Arsenic in the Zincs of Commerce, by M. SchaeufFele .... 480 



On Humus, by M. Soubeiran 481 



On a new Reagent for ascertaining the Presence of Sugar in 



certain Liquids, by M. Maumene 482 



Formation of Asp£u*tic Acid with Bimalate of Ammonia, by M. 



Dessaignes 482 



Description of an Apparatus for regulating the Heat produced 



by a Gas-burner, by Alexander Kemp 483 



On some Phsenomena of defective Vision, by R. T. Cranmore. . 485 

 On the Existence of Iodine in Freshwater Plants, by M. Ad. 



Chatin 486 



Meteorological Observations for April 1850 487 



Table 488 



NUMBER CCXLVL— SUPPLEMENT TO VOL. XXXVI. 



Prof. Donkin on the Geometrical Interpretation of Quaternions 489 

 Mr. R. Phillips on the Electricities of Steam 503 



