n .CONTENTS. 



JUNE, 180L 



Engravings of the following Objefts : 1 . An improved Jib for a Crane, by Mr. 

 Bramah ; 2. New filtering Apparatus, by Meffrs. Harman and Dearn ; 3 Gal- 

 vanic Apparatus ; 4. An ancient Lock ufed in Egypt and WeRern Afia, for 



-upwards of Three Thoufand Years j 5. Developement of the Mectianilin of 

 the Lock. 



I. Letter from Mr. Ezekiel Walker, on the Methods of obferving the Longitude 

 at fea; with an Exhib tion of the very great Accuracy of the mean Refult 

 from a Number of Chronometers - - - -65 



II. On Galvanifm. By C. Wiikinfon, Efq. - - - 70 



III. On the Formation of Snow. By G. A. - - - 73 



IV. Medico Chemical JRelearches on the Vircues and Principles of Cantharldes. 

 By H. Beaupcil - - - - .76 



V. Defcription of a Galvanic Apparatus affording a large Surface for Oxida- 

 tion, and convertible into ore oi more Plates at plea.^ure. By L R. L 79 



VI. On the Difference between the EfFt£ts of Electricity and of Heat. By 

 Cit. BerthoUet - - - - - 80 



VJI. Letter from a Correfpondent I. R. I. explaining fome FaSs in Galvanifm, 

 and on other Objefls - - ' - - - 84 



VIII. On the Prefence of a new earthy Phofphate, found in the Bones of 

 Animals, which does not exift in thole of Men. By Fourcroy and Vauquelin. 

 Read before the National Inftitute - - - 85 



IX. On the Nature of Oxigen, Hidrcgen, Caloric, &c. as deduced from Galvanic 

 Experiments. By a Correrpondent - - - 88 



X. Experiments on the Yolk of Wool, followed by fome Confideratlons on 

 the Cleanfing and Bleaching ci Wool. By Cit. Vauquelin - 90 



XI. Copy of a Letter from Mr. Cuthbertlbn to Dr. Pearl'.n, communicating aa 

 important and curious diftinguiflvng Property between the Galvanic and Eie(Sl:ric 

 Fluids. Communicated by Dr. Peuifon - - - 97 



XII. Letter from a Correfpondent, ctjntaining an Obfervaticn of the fpontaneous 

 Inflammation of Paper in Nitric Acid Gas - - - 98 



XIII. Defcription of a Jib on a fiew Conftru6lion ; by Mr. J. Bramah, Engineer. 

 Communicated by the Inventor - - - - 99 



XIV. A Memoir concerning the Fafcinating Faculty which has been afcribed 

 to the Rattle-Snake, and other American Serpents. By Benjamin Smith 

 Barton, M. D. From the American Tranlaaions, Vol. IV. - 100 



XV. Some Account of an Egyptian Lock of veiy high Antiquity. Indicated 

 from Denon's Travels. By a Correfpondent. With Obfervations by W. N. 115 



XVI. On the Caufe of the different Colours of the triple Salts of Platina, and on 

 the Exiftenceof a new Metallic Subftance in that Metal. By Collet Defcotils. 

 Prefented to the Clafs of Mathematical and Phyfical Sciences of the National 

 Inftitute of France - - - - - 181 



XVII. Defcription of an Apparatus for filtering Water. By Melf. Harman 

 and Dearn, of Redriff. - - - - - 126 



XVIII. Examination of a Stone containing Potafji. By Frederic Accum, 

 Teacher of Practical Chemiltry, Pharmacy, and Mineralogy J 27 



XIX. Letter from A. Carlifle, Efq, on the Temperature of the Sea 131 



XX. Obfervations upon the Doftrine of Count Rumford, refpefling the Want 

 of d'neHi conducing Power in Fluids with regard to Heat. By Cit. Ber- 

 thoUet - - - - - - 134 



XXI. On the DI/Hculty of obtaining Alumine ina State of Purity. ByR. T. 141 

 Scientific News, 142 — New Earth, ib. — Suberic. Acid from Paper, ib. — Eafy 



and expeditious Method of preparing Copal Varnifli, ib. — Large Piece of 

 Amber, 143 — Fluoric Ether, ib. — New Method of preparing Nitric Ether, 

 by Brugnatelli, ib. — Accenfion of Sulphuretted Hidiogen Gas, by the Affuficn 

 of Nitrous Acid, by Piofelfor Lichtenberg, 144, 



4 JULY 



