?76 Scientific Intelligence. 



6. M, Cauchoix's New Achromatic Telescope — M. Cauchoix, a very 

 ingenious optician in Paris, has nearly completed an achromatic telescope, 

 of which the object-glass is twelve inches and three (juarters of an inch in 

 diameter. Its focal length is about 194 ^^^^' The glass was manufac- 

 tured by the late M. Guinand. 



MAGNETISM. 



7. Professor Hansteen s Magnetic Tour through Siberia.-^We have just 

 learned by a letter from this eminent philosopher, that he proposes to set 

 out on a magnetic tour through Siberia, for the purpose of examining the 

 intensity of the earth's magnetism in different parts of that vast country. 

 As there can be little doubt that the Storthing (national assembly) will 

 grant him the sum requisite for that purpose, he will set out in March 

 1828. This journey will be a most important one for science, and we may 

 expect to have much light thrown by Professor Hansteen's observations on 

 the curious subject of the magnetism of the earth. 



8. M» Kupjjfer on a peculiarity in the Magnetic Equator in Siberia.-— 

 In a memoir on the magnetism of the earth, presented to the Academy of 

 Sciences on the 28th May last, M. Kup'^'^er announces, that in Siberia the 

 line of no variation is surrounded to the right and left with points in which 

 the variation is easterly, or in other words, that there is easterly variation 

 on each side of the line of no variation, a fact which has never been ob- 

 served any where else. Is it not possible that there may have been a du- 

 plication of the line of no variation between the points in which the easter- 

 ly variation was observed? It is well known that in Siberia, in lat. 60, 

 the line of no variation crosses that parallel three times in the Russian em- 

 pire. This will be seen in Professor Hansteen's chart suited to 1787; 

 and since that time it is possible that two of these branches may have 

 approached so near to each other as to occasion the very remarkable ano- 

 maly mentioned by M. Kuppfer. 



The singularly irregular form of the eastern line of no variation in pas- 

 sing from Petersburg to New Holland is a subject of prominent interest, 

 and we should like to see it projected from the latest observations that can 

 be got, and compared with the chart of Professor Hansteen. In Dr Young's 

 chart, principally from Churchman, and suited to 1794, the eastern is made 

 as regular as the western line of no variation. 



HYDRODYNAMICS. 



9. Heat evolved during the Compression of Liquids*-— It was announced to 

 the Academy of Sciences on the 14th May last, that M. Despretz had found 

 that l-75th of a degree (centigrade of course) of heat is disengaged, by 

 subjecting watei- to a pressure of twenty atmospheres. 



METEOBOLOGY. 



10. Brilliant Aurora Boreales in Scotland on the 21 th and 28th August. — 



