Vol.63-. Philosophical Magazine. April 1824. 



Contents of Number 312. 



XXXIX. Letter from Robert Hare, M.D. Professor of Chemi- 

 stry in the University of Pennsylvania, to B. Silliman, Professor of 

 Chemistry in Yale College, on some improved Forms of the Galvanic 

 Deflagrator ; on the Superiority of its deflagrating Power : Also, 

 an Account of an improved Single-leaf Electrometer ; of the Combus- 

 tiou of Iron by a Jet of Sulphur in Vapour ; and of an easy Mode of 

 imitating native Chalybeate Waters page 241 



XL. Further Remarks on the Theory of Parallel Lines 246 



XLI. On the Mathematical and Astronomical Instrument Makers 

 at Paris. By Lieut. Zahrtmann 252 



XLII. Suggestions regarding some probable Sources of Error in 

 the usual Modes of ascertaining the Force of Steam 259 



XLIII. Remarks on an Article published in No. 23 of the Journal 

 of Science, and treating of the New Tables of Refraction. By J. 

 Ivory, Esq. M.A. F.R.S 261 



XLIV. Electro- and Thermo-magnetical Experiments. By Mr. 

 William Sturgeon ; 266 



XLV. Description of a Rotative Thermo-magnetical Experiment. 

 By Mr. William Sturgeon 269 



XLVI. On Parallel Straight Lines. By John Walsh, Esq 271 



XLVII. Zoological Notices. By Mr. John Edward Gray. . . 274 



XL VIII. Analysis of Professor Hausmann's Essay on the Geo- 

 logy of the Apennines 278 



XLIX. Chemical Examination of Green Feldspar from Beverly, 

 Massachusetts. By J. W. Webster, M.D 283 



L. Notices respecting New Books: — Sir J. E. Smith's English 

 Flora ; Phillips's Translation of the London Pharmacopoeia ; Ana- 

 lysis of Periodical Works of Natural History 284 — 299 



LI. Proceedings of Learned Societies :— Royal Society ; Linnaean 

 Society ; Horticultural Society ; Astronomical Society ; Medico- 

 Botanical Society ; Medical Society of London ; Asiatic Society — 

 Question relative to the Charter ; Royal Academy of Sciences at 

 Paris 299—307 



LII. Intelligence and Miscellaneous Articles : — Bessel's Method 

 of ascertaining the Corrections of the Readings of Thermometers ; 

 Elements of the Comet of 1823 — 24, by various Computers ; Ano- 

 maly in the Figure of the Earth ; The Rate of a Chronometer 

 varies with the Density of the Medium in which it is placed ; Note 

 on the Existence of a Nitrate and a Salt of Potash in Cheltenham 

 Water, by M. Faraday, &c. ; The Logan Stone in Cornwall over- 

 turned ; Obituary — Mr. John Forbes ; Calendar of Flora, Fauna, 

 and Pomona, at Hartfield in Sussex ; Additions to Professor Hare's 

 Paper; List of New Patents; Meteorological Table, &c 307 — ."-20 



* # * Communications for this Work, received by the Editors, 

 3S, Shoe-Lane, will meet with every attention. 



