PREFACE. 



Of the Engravings, the Subjects are, 1. A very simple 

 and perfectly safe Gun Lock, by Mr. Dodd. 2. The framing 

 of a Field Gate with a considerable Accession of Strength, 

 by Mr. Waistell. 3. A Compensation Curb for a Time 

 Piece, by Mr. Scott. 5, 6. Plans and Sections of the Ba- 

 varian Salt Works. 7. Captain Brodie's Method of connect- 

 ing Iron Bars, and coating them with Lead. 8. Mr. Rawlin- 

 son's \rill for grinding Colours. 9. Apparatus for grinding 

 Indigo and other dry Materials. 10. Method of banking the 

 Balance of a Time Piece, by Mr. Hardy. 1 L A Pyrometer 

 for meafuring the Heat of a Furnace, by Mr. J. G. F. 

 Schmidt. 12. A Portable Steam Engine, by Mr. Murray. 

 13. Apparatus for making the Gaseous Oxide of Carbon, by 

 Mr. Baruel. 14. A Topographical Plan by Mr. Churchman, 

 in which the Elevations and Depressions of the Surface of 

 the Earth, are by a new Method correctly delienated. 15. 

 Mr.Gregory's Apparatus for measuring the Power of Horfes. 

 1 6. The American Borer. 17. Diagram illustrative of Optics, 

 by Mr. Ezekiel Walker. 18. Mr. Sepping's Blocks for 

 supporting and suspending Ships. 19. Count Rumford's 

 Apparatus for illustrating his Experiments in Proof, that the 

 greatest Density of Water is higher than the freezing Point. 



20. A Valve for Steam Engines, by the Chevalier Edelcrant^, 



21. Figures and Diagrams, by Edward Pigott, Efq. to illu- 

 strate the Causes of Periodical Decrease in Diminution of 

 Light, in a Star in Sobiefki*s Shield. 22. A Press for Botani- 

 cal Specimens, by Mr. Harrison. 



Sohif Squat d, London, September 1, 1S05. 



