CONTENTS. -vii 



AUGUST 1806. 



Kngravings of the following Objects : 1. The Thermometrical Balance of Peter 

 Le Kov ; being the first which ever was cppstructed; i'. The Expansion Ba- 

 lance with Arms of Brass and Steel; constructed apd published bythesarnc 

 Artist at least twelve Years before Arnold took out his Patent for it ; 3. The 

 modem detached Escapement, as it was constructed byLeKoy in 1748; 4. 

 The same improved, so as to have no Eecpil nor Spring in the Detent ; 5. The 

 same, as altered by Berthoud in two Constiucliong ; (). The same by Arnold, 

 constituting Part of the Disclosure for \vhicl) he had a Reward of Three Thou- 

 sand Pounds ; 7. The same by Earnshaw, who received a like Keward. 



I. Outline of the principal Inventions by which Timekeepers have been brought 

 to their present Degree of Perfection, lleccived from a Correspondent; £7i 



JJ. Account of a Series of Experii-jients, shewing the Effects of Compression m 

 modifying the Effects of Heat. By Sir James Hall, Bart. F. K. S. Edin- 

 burgh. - - ^ - - - 302 



HI. Catalogue of thirty-one Specimens, shewing the Result of Sir James Hall's 

 ICxperiments on the Effects of Heat modifiett by Compression, which were 

 deposited by him in the British Museum, on the 29th of June, 180d. 3 M 



IV. Enumeration of several Cases of Ships which have been struck by Light- 

 ning; the destructive Effects having acted in a vertical Direction towards the 

 Centre of the Earth, and never horizontally. In a Letter from James Hors- 

 burgh, Esq. - ' „■ - _ ojg 



y. Letter from G. S. Gibbes, M. D. shewing that the Bath Waters contain a 

 ' much greater Portion of Iron than has hitherto been supposed. - 32J( 



VI, Letter of Inquiry respecting theCaxise why Men cannot swim without pre- 

 ■ vious Education as well as Brutes. From a Correspondent, R.B. With vari- 

 ous Observations by the Editor. - -• - 324^ 



yil. Facts towards forming a History of Gold. By Professor Proust. 331 



VIII. Account of an Appearance of Brighton Cliff seen in the Air by Eeflection. 

 In a Letter from Dr. Buchan. - - - '- 340 



IX. Letter from Dr. Wilkinson, respecting the supposed Production of Muriatic 

 ' Acid from \Vater by Galvanibm. ■- ^ - 24? 



X- Letter from H. Hamill, jun, Esq. on thp Measure of a Ship's Velocity. 343 



XI. Facts relating to the Art of Shaving. From a Correspondent. 344 



XII. Account of the late Eruption of Mount Vesuvius. - 345 



Xni- Scientific News: — Galvanic Society of France, 350. — Craniologic System 

 of Gall, ib.— Greek Manuscripts probably existing in Russia, 331. — ^To Cof 

 respondents, 353. • 



SUPPLEMENTo 



