160 Foreign Literature and Science. 



on the contrary, separates during the solidification of the 

 metal, in forming graphite, whose particles by an intimate 

 mixture with the rest of the mass, give to the cast iron the 

 gray fracture. 



A sudden cooling not permitting the successive formation 

 of graphite, always occasions a white fracture. 



5. There are substances which, united to iron, prevent 

 this separation of carbon, under the form of graphite, such 

 as phosphorus, sulphur, the metallic bases, earthy oxides, 

 &c. and other metals especially manganese. In this case, 

 the cast iron which contains as much or more carbon than 

 the greyish variety, preserves the white fracture even after it 

 has been cooled as slowly, and as carefullly as possible. 



II. Pure Iron. Forged Iron. — Forged iron is consider- 

 ed as pure iron containing foreign substances, (especially 

 carbon,) in too small quantities to alter its properties. The 

 different varieties depend on the properties, more or less in- 

 jurious, which these substances communicate. 



III. Steel. — Its chemical composition appears to be iden- 

 tical with that of white cast iron, that is to say it is formed 

 of pure iron, carbon and a third body, such as aluminum, sili- 

 cium, manganese, &c. &c. which renders stable the union 

 of the carbon and the iron. The difference between white 

 cast iron and steel, appears to reside according to M. Mul- 

 ler, only in the mechanical arrangement of the molecules. — 

 Annales des Mines, Tome 13, 1826. 



3. Astronomical Observatory. — His Majesty the King of 

 the Netherlands whose munificence in the encouragement of 

 public instruction, is constantly active, has just given a new 

 Ordinance for the establishment of an Observatory at Brus- 

 sels. The Regency of the city with a view to second so hon- 

 orable a project, has asked permission to share in the ex- 

 pences of its erection and has offered a site in one of the 

 most beautiful quarters of the city. The care of preparing 

 the plan has been confided to M. A. Quetelet, professor of 

 Mathematics and Astronomy at the Museum, and who is to be 

 associated with M. Walter, Inspector General of public in- 

 struction. 



They are also occupied at Brussels, at the present time, in 

 the formation of a vast Botanic garden, destined, principally 

 to favor the progress of horticulture. The purchase of the 



