CONTENTS 
OF 
No. XXVI. 
Page 
Art. I. General reflections on various important subjects in 
Mineralogy. By Frederick Mohs, Kniglit of the 
Order of Civil Merit, Professor of Mineralogy at 
Freyberg. Fellow of the Royal Society of Edin- 
burgh, of the Wernerian Natural History Society, 
&c. Communicated by the author, - 205 
II. Contributions to the British Fauna. By George John- 
ston, M. D. Fellow of the Royal College of Surgeons, 
Edinburgh, - - - 218 
III. On the Sodalite of Vesuvius. By William Haidin- 
ger. Esq. F.R.S. E. & M.W.S. (With a Plate). 222 
IV. New Corrections for the Effects of Humidity on the 
Formula for measuring Heights by the Barometer. 
By Adam Anderson, A.M. F. R.S.E. Rector of the 
Academy of Perth. (Continued from Vol. XII. 
p. 260.), - - 224 
V. On the Action of certain Fluids on Hydrhopic Sub- 
stances of an Animal and Vegetable Origin, By 
Henry Home Blackadder, Esq. Surgeon, 240 
VI. On Steam-Boats. By Thomas Tredgold, Esq. Civil 
Engineer, and Honorary Member of the Institution 
of Civil Engineers of London, &c. (With a Plate). 244 
VII. Sketch of the Geology of Sicily. By Charles Dau- 
beny, M.D. F.R.S. Professor of Chemistry in the 
University of Oxford. (Continued from p. 118.), 254 
VIII. Description of a Sitometer, or Instrument for mea- 
suring Grain. By Henry Stephens, Esq. B alma- 
dies. (With a Plate). - - 2 6$ 
