PREFACE. 



iHE Authors of Original Papers and Communications in the 

 _ present Volume are Mrs. Agnes Ibbetson ; J. J), Maycock, 

 Esq. ; Mr. G J. Singer ; Mr. E. Lydiatt ; Mr. John Davy ; W. Crane, 

 Esq. F. R. M. S. Ed. ; Mr. R. Lyall, M. R. P. S. E. &e.; R. L. 

 Edgeworth, Esq. F. R. S. M. R. I. A. ; L. O. C ; T. A. Knight, 

 Esq. F. R. S. &c. ; Mr. J. Dalton ; the Rev. J. Blanchard ; J. Clarke, 

 M. D.; Mr. J. T. Price; Mr. St. Amand; T. Forster, Esq.; Mr. 

 J. Murray ; Marshall Hall, Esq. ; W. Moore, Esq. ; Mathema- 

 ticus ; Mr. B. Cook ; W, N. ; Zeno. 



Of Foreign Works, Messrs. Gay-Lussac and Thenard; M. 

 Begnier ; M. Van Meerten ; M. Stratingh ; M. Cagniard Latour ; 

 M. delaChabeaussiere ;Mr.G. B, Sage ;M.Bucholz ; M.Daubuisson ; 

 M. Cordier; Dr. B. H. Tarry; M. C, Dumeril; M. L. Cordier; 

 M. Hassenfratz. 



And of British Memoirs abridged or extracted, T. Thomson, 

 M. D. F. R. S, E. &c. ; the Rev. J. Bremner ; T. A. Knight, Esq. 

 F. R. S. &c. ; H. Davy, Esq. LL. D. Sec. R. S. Prof. Chem. R. I. 

 F. R. S. E. ; Mr. E. Smith; Mr. J. Hutton, junr, ; H. P. Lee, Esq. ; 

 the Rev. J. Hall; Mr. T. Balls; Mr. J. Bkker; Mr. W. Jeffery ; 

 Mr. J. Davis; Mr. W. Moult; Mr. B. Smith; Mr. J, Taylor; B. 

 C. Brodie, Esq. F. R. S. 



The Engravings consist of 1. Dissections of Plants, illustrating 

 the Growth of the Bud, by Mrs. A. Ibbetson. 2 Crystals of Al- 

 lanite, by Dr. T. Thompson. 3. Instruments for measuring the 

 Velocity of Rivers, by Mr. Regnier. 4. Method of covering a 

 Roof wfth Flagstones, by R. L. Edgeworth, Esq. F. R. S. M. R. I. A. 

 5. A Ship's ordinary Boats converted into Lifeboats, by the Rev. 

 J. Bremner. 6. A Barometer with an adjusting Scale, and 7. 

 An Airpump for producing a perfect Vacuum, by a Correspon- 

 dent. 8. Section of a Grapehouse, by T. A. Knight, Esq. F. R. 

 (.. and H. SS. 9. Figures to illustrate the Formation of the Leaves 

 of Firs, and their Fructification, and the Motion of the Flower 

 of the Barberry ; delineated by Mrs. Agnes Ibbetson. 10. A Dia- 

 gram illustrating the Radiation of Cold, by Marshall Hall, Esq. 

 U- Diagrams illustrative of the Motion of Rockets, by W. Moore, 

 Esq. 12. A new Thrashing Machine, invented by H. P. Lee, 

 Esq. 13. A Screw adjusting Plough, by Mr. Thomas Balls. 14. 

 An improved Implement for extirpating Docks and Thistles, by 

 Mr. J. Baker. 15. A pair of expanding Harrows, by Mr. Wm. 

 Jeffery. 16. Mr. J. Davis's Fire-escape. 17. Mr. W. Moult's 

 Filtering Apparatus. 18. Mr. B. Smith's Method of Relieving a 

 Horfe, that has fallen in the Shafts of a loaded Cart. 19. Mr. J. 

 1 aylor's Extractor of ^oul Air from Mines, &c. 



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