234 Notices of Scientific Works. [April, 



oxymuriate of potash ; the diamond was supported in the centre of 

 this glohe by a rod of platinum, to the top of "which a cradle or cap 

 was fixed, pierced full of holes to allow a free circulation of the gas 

 about the diamond. The Duke's burning-glass was the instrument 

 used to apply heat to the diamond. It consists of two double convex 

 lenses, distant from each other about 3|- feet ; the large lens is about 

 14 or 15 inches in diameter. The instrument is fixed in the centre 

 of a round table, and is so arranged to admit of elevation or depres- 

 sion, or any adjustment required, at pleasure. By means of the 

 second lens the focus is very much reduced, and the heat, when the 

 sun shines brightly, rendered very intense. 



" The instrument was placed in an upper room of the museum ; 

 and having arranged it at the window, the diamond was placed in 

 the focus, and anxiously watched. The heat was thus continued at 

 intervals for three-quarters of an hour (it being necessary to cool 

 the globe at times), and during that time it was thought that the 



diamond was slowly diminishing and becoming opaque 



On a sudden Sir H. Davy observed the diamond to burn visibly, 

 and when removed from the focus it was found to be in a state of 

 active and rapid combustion. The diamond glowed brilliantly with 

 a scarlet light inclining to purple, and when placed in the dark con- 

 tinued to burn for about four minutes. After cooling the glass, heat 

 was again applied to the diamond, and it burnt again, though not 

 nearly so long as before. This was repeated twice more, and soon 

 after the diamond became all consumed. This phenomenon of actual 

 and vivid combustion, which has never been observed before, was 

 attributed by Sir H. Davy to the free access of air. It became more 

 dull as carbonic acid gas formed, and did not last so long. The 

 globe and contents were put by for future examination." 



Eeturningto England, Faraday was, in 1815, officially appointed 

 to be chemical assistant at the Eoyal Institution. As such he con- 

 tinued for some ten years, when, having already given occasional 

 lectures, first in the laboratory, and then in the theatre of the 

 Eoyal Institution, he was permanently appointed to the position he 

 held until his death. In 1816 Faraday published his first contribu- 

 tion to science in the then ' Quarterly Journal of Science ; ' this was 

 rapidly followed, by other papers on very diverse subjects, and it 

 was not until 1831 he began the great work of his life, the 

 ' Experimental Eesearches in Electricity.' It will be unnecessary to 

 refer to these researches here, for our readers are probably acquainted 

 with their magnitude and importance. Unswervingly were they 

 pursued until, in 1855, he sent the thirtieth, and last, of the series 

 to the Eoyal Society. 



Eemembering his even life, many are surprised that Faraday 

 found it necessary to relinquish his great work at an age in which 

 most of our statesmen are in their very prime. When, however, 



