CONTENTS. 



Page 



On the Formation of an Artificial Compound Dispersive Power in 

 a Compound Lens, for correcting the Front Lens of a Refract- 

 ing Telescope. By PETER BARLOW, F.R.S., Cor. Mem. Inst 

 France, &c. . . . . . I' 



On those Birds which exhibit the Typical Perfection of the Family 

 of Anatidae. By WILLIAM SWAINSON, Esq. F.R.S., L.S., &c. 1 1 



On the Relation between the Polyhedral and Spheroidal Theories 

 of Crystallization ; and the Connexion of the latter with the 

 Experiments of Professor Mitscherlich. By J. F. DANIELL, 

 F.R.S., Professor of Chemistry in King's College, London . 30 



On the Illumination of Theatres. By A. AINGER, Esq. . .45 



On the Red Solutions of Manganese. By THOMAS J. PEARSALL, 

 Chemical Assistant in the Royal Institution . .49 



On the Comparison of British, French, and Dutch Weights. By 

 Dr. G. Moll, Professor in the University of Utrecht. [Com- 

 municated by the Author] . . . . .64 



I. On a Remarkable Case of Coryza Phlegmatica. II. On the 

 direct Formation of Oxide of Iodine and lodous Acid. III. On 

 Nitrogen in Natural Waters. By the CAVALIERS LUIGI 

 SEMENTINI, of Naples, M.R.I., &c., in a Letter addressed to 

 the Secretary of the Royal Institution . . .75 



On the Direction of the Radicle and Germen during the Vegetation 

 of Seeds. By THOMAS ANDREW KNIGHT, Esq., F.R.S , Pre- 

 sident of the Horticultural Society, &c. . . .80 



On Disinfection and the Practice of Quarantine ; with some Re- 

 marks and Communications relative to Contagious Disease, 

 and especially the Cholera. By ANDREW URE, M.D., F.R.S. , 

 &c. &c. 83 



