Just published, in quarto, Price Tiiirty Shillings, 



Illustrated by Nine highly-finished Engravings ; viz. Four large folding Plates of 

 the Survey of the Thames, and the Instruments employed ; one Quarto and 

 two folding Plates of the Graphical Registrer of the Tides and Wind, and two 

 Quarto Plates of the Magnetic Apparatus, and Illustrations of the paper ; 



THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL 

 SOCIETY of LONDON, 1831, Part L 

 Contents: — Capt. Robertson's Observations on the Comet of 1822. 

 — Prof. Barlow on Fluid Refracting Telescopes.— Lubbock's Re- 

 searches in Physical Astronomy — Harris on the Transient Magnetic 

 State of Substances. — Gilbert on Negative and Imaginary Quantities.— 

 Prof. Barlow on the Phaenomena of Terrestrial Magnetism. — Ivory on 

 the Equilibrium of Fluids. — Prof. Davy on an Electro-Chemical Method 

 of detecting Metallic Poisons. — Barry on Atmospheric Electricity. — 

 Lloyd's Survey of the River Thames from London Bridge to the Sea. — 

 Fox on the Variable Intensity of Terrestrial Magnetism. — Palmer on a 

 Graphical Registrer of Tides and Winds. — Prof. Barlow on the Errors 

 in the Course of Vessels frttm Local Attraction. — Lubbock on the Me- 

 teorological Observations made at the Royal Society. — Meteorological 

 Journal of the Royal Society, June to December 1830. 



This Day is published, in one thick volume, 12mo, with lO* Wood-cuts, 



Price IBs. 



A 



GEOLOGICAL MANUAL. By HENRY T. DE LA BECHE, 

 Esq. F.R.S. F.G.S. Mem, Geological Society of France, &c. 



Printed for Treuttel, Wiirtz, and Co. 30, Soho-Square. 



