iv , CONTENTS. 



J ij N E 1800. 



Engravings of the following Objefts , 1 . Plan of the Air Vault and BlowiRg 

 Apparatus of the Devon Iron Works ; and, 2. Additional Machinery to be 

 added to the Hydraulic Engine of Schemnitz, to make it perform its Rece- 

 procations without Attendance. By Mr. J. W. Bofwell. 



I. Obfei"vations on the Proofs of the Huttonian Theory of the Earth, adduced 

 by Sir James Hall, Bart. By R. Kirwan, Efq. Communicated by the 

 Author. - - - - - - p. 97 



II. Experiments on the Combuftion of Diamond, the Formation of Steel by its 

 Combination with Iron, and the pretended Tranfmiffion of Carbon through 

 the Veffels. By Sir G. S. Mackenzie, Bart. - - p. 103 



In the combuftion of diamonds under a muffle, the phenomena were obferved. It begins to take 



place at about 1 1° Wedgwood. Gayton's experiment of the converfion of iron into fteel.by 



the diamond, was repeated with complete fuccef< : temperature 150° Wedgwood. The fame 



treatment of iron, without the diamond, does not afford ftccl; neither does carbon penetrate 



* the vcflels in ftrong lire. Oxide of iron reduced by diamond powder. 



III. Account of certain Phenomena obferved in the Air Vault of the Furnaces 

 of the Devon Iron Works, together with fome praftical Remarks on the 

 Management of Blaft Furnaces. By Mr. John Roebuck, in a Letter to Sir 

 James Hall, Bart. - - - - p. 110 



'Ihe air vault is a large chamber cut in the folid rock. When Mr. R. was in this vault while in 

 work, the air being forced in by a fleam engine, fo as to fupport a colum.n of between five and 

 iix inches of mercury, with a receprocation of half an inch, a number of remarkable fads pre- 

 fented themfelves. Great ad\antages in the exjienditure of power wlien the ftream of air ii 

 made to pafs with a moderate velocity. 



IV. Apparatus for making the Hydraulic Engine at Schemnitz work itfelf 

 v^ithout Attendance. By Mr. John Whitley Bofwell. - p. 117 



V. On the Chemical A£lion of different Metals upon each other at the common 

 Temperature of the Atmofphere, and upon the Explanation of certaip Gal- 

 vanic Phenomena. By M. Fabbroni. , - - - p. 120 



As early as the year 1792, M. Fabbroni had made experiments and inductions refpecling the ex- 

 periment of Sulfzer, publiihed in 1767, and fince clafl'ed among the Galvanic plienomcna. 

 Enumeration of thofo experiments. Oxidation takes place by their mutual a(5lion when water is 

 prefcnt. The author afcribes the effefts to this oxidation, and gives niany reafons in fupport 

 of his opinion, that eleftricity is not at all concerned in phenomena of this nature, 



VI. Report concerning the Art of making fine Cutlery.— W. N. p. 127 



VII. Thoughts on Magnetifm. By Richard Kirwan, Efq. LL. D, F. R.S. 

 ^nd, M.R.I. A. (Concluded from p. 94.) - - p. 133 



VIII. On 



