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chemist. In pouring the metal into the mould, if it is too 

 hot the experiment will fail, and also if too cold. There is 

 an intermediate degree of heat to which the metal should be 

 reduced, and this might be obtained by the following chemical 

 test. All chemists are aware that on the melting of metals 

 there would be an oxyde formed on the surface. But they 

 were also aware that a piece of wood of a carbonaceous sub- 

 stance would reduce that oxyde and convert it to metal. 

 This was the means which the Earl of Rosse had adopted 

 to reduce the oxyde, and the moment that effect was pro- 

 duced, the metal was in a fit condition to pour into the 

 mould. Great difficulty had also arisen with respect to the 

 grinding and figuring of the speculum ; but Lord Rosse 

 had also succeeded in overcoming this obstacle by the con- 

 trivance of a simple piece of machinery, whereby he was 

 enabled to perform the operation under an equal temperature, 

 which was most essential to the perfection of the speculum. 

 Having described the manner in which this great instrument 

 is fixed for the purposes of observation, Dr. Scoresby pro- 

 ceeded to give an interesting account of its performances. 

 The instrument was first brought into operation in the spring 

 of last year, and in the course of one month there were no 

 less than forty-three nebulse resolved into distinct stars by its 

 aid, those nebulae having hitherto appeared, through other 

 instruments, to be merely obscure specks. This was a 

 fact which led him to apprehend that those who were 

 advocates of the nebulae theory would, ere long, abandon 

 the idea of their being luminous matter in the process of 

 being formed into suns or worlds. Dr. Robinson, of 

 Armagh, stated that, with Lord Rosse's telescope, stars 

 which Herschel described as of the fifteenth magnitude, 

 were as brilliant as stars of the first magnitude seen by a 

 telescope of three or four feet in length. He next referred 

 to the indescribably gorgeous appearance of the surface of 



