11 
CONTENTS. 
Art. XV. Table of Proportional Logarithms to Twenty-four 
HourS;, with the method of using it, - 95 
XVI. On the Optical and General Properties of Taba- 
sheer. By David Brewster, LL.D. F. R. S. 
Lond. & Edin. > „ 97 
XVII. Account of the Ayrshire Rose. In a communica- 
“ tion from Mr Neill, Secretary of the Caledonian 
Horticultural Society, - - 102 
XVIII. On the Depth and Temperature of the Lake of 
Geneva, by Mr H. T. De la Beche. Commu- 
nicated by Professor Pictet, - 107 
XIX., Account of the celebrated Slide of Alpnach, con- 
structed on Mount Pilatus by M. Rupp, Engi- 
neer. Communicated by Professor Pictet, HO 
XX. On certain Optical Phenomena exhibited by Mo- 
ther-of- Pearl, depending on its intenial structure. 
By J. F. W. Herschel, Esq. F. R. S. &c. 114- 
XXL Account of Micrometers for Measuring Distances. 
By the late James Watt, LL.D. F. R. S. &c. 121 
XXII. Account of Mr Morton’s Patent Slip, for hauling 
Vessels out of the water to be repaired, &c. 125 
XXIII. Notice regarding the State of the Scottish Fisheries 
in August 18 19. In a Letter from Robert Ste- 
venson, Esq. F. R. S. E. Civil Engineer, 129 
XXIV. Account of a new Method of Uniting Bee-Hives. 
Communicated by the Rev. Andrew Jameson, 
M.W.S. . - 133 
XXV. Account of an Improved Catoptrical Microscope, 
by Professor Amici of Modena, - 135 
XXVI. Account of the Discovery of the Shetland Cod- 
Bank in the summer of 1818. In a communica- 
tion from Samuel Hibbert, M. D. M. W. S. &c. 138 
XXVII. Account of M. Fresnel’s Discoveries respecting 
the Inflexion of Light, - - 150 
XXVIII. Some Additional Facts relating to the habitudes of 
the Flyposulphiirous Acid, and its union with 
Metallic Oxides. By J. F. W. Herschel, Esq. 
F,R.S. &c. ^ - 154, 
XXIX. Notice of a Mineralogical Journey through South, 
North and East Iceland, by Mr John Menge of 
Hanaii. In a Letter addressed to Professor Jame- 
son, - - “ 156 
