iSlSj Imperial Imiiiute of France, 315 



Among the works sent by the correspondents of the Class^ 

 we may notice two Danish Charts, transmitted by M. Bugge^ 

 Astronomer Royal at Copenhagen : a memoir on the Construc- 

 tion of Iron Bridges, by M. Wiebeking: a complete treatise on 

 the Theory and Practice of Levellmg, by M. Fabre, chief engi- 

 neer des ponts et chaussees, 



" Accounts of the works presented to the Imperial Institute by 

 philosophers not members have, as usual, occupied a part of the 

 meetings of the Class, and of the time of those members to 

 whom the examination of them was committed. As we shall 

 notice here only the objects which have received the fullest 

 approbation, we shall confine ourselves to the memoire, of which 

 the following are the titles: — 



" Memoir of M. Caucbv, on Fohjgovs and Pchjhedrons, M. 

 Legendre has inserted the results into his Elements. 



" Pla'm and Ohject Glasses, by M. le Rebours. In consequence 

 of this Report, t Board of Longitude obtained for the Imperial 

 Observatory a telescope of M. Rebours, which appears the 

 best that exists of the same dimensions. 



Memoir on radiant Heat, by M. Frangois de la Roche. 



Memoir of M. Binet, jun. on the Calculation of the Pla- 

 netary Disturlances, 



New Hydraidic Machine, by M. Lingois, 



Experi7nents of M. Jecker in Optics, Navigation, and As- 

 tronomy, 



Memoir of M. Gauthler on the general methods of con- 

 strticting graphically a circle determined by three conditions, and 

 a Sphere determined hj four, 



" Memoir of M. Servois, to destroy the Differential Calcidiis 

 of the Calculus of Differences. 



New Stocking Loom, by M. Favreau. On occasion of this 

 memoir, M. Desmarets, the reporter, collected the improve- 

 ments which other artists had formerly introduced into this 

 machine. He composed a paper on the subject, which the Class 

 judged useful to the history of the art, and which it ordered to be 

 printed in a succeeding volume. 



At the last meeting of the year the Class heard two very 

 interesting reports. One on a manuscript work, entitled 

 Developements of Rational and Analytical Geometry, coniaining 

 the theory of the Curvatures of Surfaces, ivith applications to 

 the Stahitity of Vessels, to Loading and Unloading^ and to 

 Optics, by M. Dupin, Capitaine du Corps de GenieMilitaire, 

 This manuscript constitutes part of a more considerable work, 

 which the author means to submit to the judgment of the Class, 

 and which is the fruit of the few moments of leisure adbrded 

 him in a very active service, with continual change of place. 

 The other memoir had for its object vai'ious machines by means 



