CONTENTS. v 



XX. On the Theoretical Investigation of the Absolute Intensity of Interfering 

 Light. By The Rev. P. KELLAND, AM., F.R.SS. Lond. and 

 Edin., F.C.P.S., Professor of Mathematics in the University of Edin- 

 burgh, . . ....... Page 315 



XXI. Analysis of Caporcianite and Phakolite, two new Minerals of the Zeolite 

 Family. By THOMAS ANDEESON, M.D., Edin. Communicated 

 by Dr CHKISTISON, 331 



PART III. 



XXII. On the Property belonging to Charcoal and Plumbago, in fine Plates 

 and Particles, of Transmitting Light. By JOHN DAVY, M.D., 

 F.R.SS. L. $ E., Inspector-General of Army Hospitals, L.R., 335 



XXIII. On the Growth of Grilse and Salmon. By Mr ANDREW YOUNG, 



Invershin, Sutherlandshire. In a Letter addressed to JAMES 

 WILSON, Esq., F.R.S.E. Communicated by Mr WILSON, 343 



XXIV. On the Law of Visible Position in Single and Binocular Vision, and 



on the representation of Solid Figures by the union of dissimilar 

 Plane Pictures on the Retina. By Sir DAVID BREWSTER, 

 K.H., D.C.L., F.R.S., and V.P.R.S.E., .... 349 



XXV. On the Growth and Migrations of the Sea-Trout of the Solway 

 (Salmo trutta). By Mr JOHN SHAW, Drumlanrig. Communi- 

 cated by Mr WILSON, 369 



XXVI. On the Optical Phenomena, Nature, . and Locality of Muscce Voli- 

 tantesj with Observations on the Structure of the Vitreous Humour, 

 and on the Vision of Objects placed within the Eye. By Sir 

 DAVID BREWSTER, K.H., D.C.L., F.R.S., and V.P.R.S.E., 377 



XXVII. On the Specific Gravity of certain Substances commonly considered 

 lighter than Water. By JOHN DAVY, M.D., F.R.SS. L. $ E., 

 Inspector-General of Army Hospitals, L.R., . . . 387 



XXVIII. Biographical Notice of the late Sir CHARLES BELL, K.H. By Sir 



JOHN M'NEILL, G.C.B., 397 



VOL. XV. b 



