IV CONTENTS. 



Page 



XIII. Notice on the Elastic Force of Vapour. By Richard Tregaskis. 

 Esq. Communicated by the Author, - - - 282 



XIV. Description of some remarkable Nebulae and Clusters of Stars in the 

 Southern Hemisphere, observed at Paramatta in New South Wales. 



By James Dunlop, Esq. - - - - 282 



XV. Table of the Refractive Powers of several Bodies, according to the 

 observations of J. F. W. Herschel, Esq. V. P. R. S. &c. With 

 remarks by the Editor, - . - 296 



XVI. Approximate places of Double Stars in the Southern Hemisphere ob- 

 served at Paramatta in New South Wales. By James Dunlop, 

 Esq. In a Letter to Sir T. Macdougal Brisbane, K. C. B., 

 F. R. S. Lond. and Edin. - - - - 301 



XVII. Account of an Experiment made on the composition of Oil of Cassia, 

 to determine the cause of its high dispersive power, by J. F. W. 

 Herschel, Esq. V. P. R. S. &c. &c- - ... 308 



XVIII. Contributions to Physical Geography, _ - . 310 



1. Account of the Eruptions of Mount ^tna. By L. Sibiond, ib. 



2. Account of thei^arge Chestnut of Mount iEtna. By L. Sisiond, 314 



3. Account of the Falls of Niagara, - - - 316 



4. Account of a Storm in the Desert, - - 319 



5. Burning Springs in America, - - - - 321 

 XIX. Meteorological Register kept at Kinfauns Castle, the seat of the Right 



Honourable Lord Gray, - - - - 323 



XX. Account of a remarkable peculiarity in the Structure of Glauberite, 

 which has One Axis of Double Refraction for Violet, and Two Axes 

 for Red Light. By David Brewster, LL. D., F. R. S. Lond. 

 and Edin. - - ... 325 



XXI. Account of the Single Lens Microscopes of Sapphire and Diamond, ex- 

 ecuted by Mr A. Prit chard. Optician, London, - 327 



XXII. On the Defects of the Sympiesometer, as applied to the Measurement 

 of Heights. By James D. Forbes, Esq. Commuricated by the Au- 

 thor, - - - - - - 334 



XXIII. On the influence of Light on the motions of Infusoria. By R. E. 

 Grant, M. D., F. R. S. E., F. L. S., Professor of Zoology and 

 Comparative Anatomy in the University of London. Communicated 



by the Author, - - - - - 346 



XXIV. Farther observations on the Generation of the Virgularia MiraUlis. 

 By R. E. Grant, M. D., F. R. S. E., F. L. S., Professor of Zoology 

 and Comparative Anatomy in the University of London. Commu- 

 nicated by the Author, . . - . . 350 



XXV. ZOOLOGICAL COLLECTIONS, - - 351 



1 Observations on the Mantis Tribe, or that of the Leaf Insects. By 

 Dr Adam, . . - - ib. 



2. Account of a Singular Species of Mollusca from the Coast of Cey- 

 lon. By James Calder, Esq. - - - 352 



3. Experiments on the effects produced by dividing the semicircular 

 canals in the Ears of Birds. By M. Flourens, - 353 



