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Fossil coal flora
424
Eddies.
[Jour. Frank. Inst.,
E d d i e s . - - I n Faye's communication to the French Academy on the movement of tempests, he referred to a memoir of M. Belgrand's upon the eddies of running water. In some subsequent remarks Belgrand stated that every modification of the bed of a river produces eddies which diminish the velocity of water. The phenomenon is so common as to attract little attention. The well-determined causes, which may give some idea of the movements of the atmosphere or of the erosion of valleys, he considered under three heads : 1. Eddies which bring the water from the middle towards the banks of a water course; 2. Eddies at bends ; 3. Eddies at the junction of confluents. He illustrated his remarks by references to numerous geological results, especially along the banks of the Seine, the Marne, and the Yonne.--Gomptes Rendus. C.
Fossil Coal F l o r a . - - T h e Annales des Mines contains a summary covering fifty pages, of Grand' Eury's works upon the determination of the age of coal beds, by the aid of fossil flora. His first memoir was presented to the Academy of Sciences, and submitted to the examination of a commission, composed of MM. Daubrde, Tulasne, and Brongniart. M. Brongniart's report, which was inserted in the Gomptes Rendus of August 12th, 1872, recommended the insertion of the memoir in fall, in the Memoires des Savants Etrangers, which recommendation was adopted by the academy; but M. Grand' Eury continued and enlarged his work by new discoveries, so that it did not appear until 1877. Soon after it was published it received one of the gold medals from the general union of learned societies. While adopting most of the conclusions of Ginetz, Brongniart and Gruner, his systematic botanical and geological classifications and divisions have greatly enlarged our knowledge of the French carboniferous flora, and his work is one of the most valuable contributions to vegetable pal~eontology which has appeared for many years. C. The Giffard B a l l o o n . - - T h e captive balloon for the Universal Exposition is nearly completed. It has a capacity of 25,000 cubic metres, and a diameter of 86 metres. The bag is made of alternate sheets of calico and caoutchouc, and is supposed to be impermeable to hydrogen. It will be inflated with pure hydrogen, prepared on the spot from iron filings and sulphuric acid. It will be able to raise fifty persons to a height of more than 500 metres.--Zes Mondes. C.
Eddies.
[Jour. Frank. Inst.,
E d d i e s . - - I n Faye's communication to the French Academy on the movement of tempests, he referred to a memoir of M. Belgrand's upon the eddies of running water. In some subsequent remarks Belgrand stated that every modification of the bed of a river produces eddies which diminish the velocity of water. The phenomenon is so common as to attract little attention. The well-determined causes, which may give some idea of the movements of the atmosphere or of the erosion of valleys, he considered under three heads : 1. Eddies which bring the water from the middle towards the banks of a water course; 2. Eddies at bends ; 3. Eddies at the junction of confluents. He illustrated his remarks by references to numerous geological results, especially along the banks of the Seine, the Marne, and the Yonne.--Gomptes Rendus. C.
Fossil Coal F l o r a . - - T h e Annales des Mines contains a summary covering fifty pages, of Grand' Eury's works upon the determination of the age of coal beds, by the aid of fossil flora. His first memoir was presented to the Academy of Sciences, and submitted to the examination of a commission, composed of MM. Daubrde, Tulasne, and Brongniart. M. Brongniart's report, which was inserted in the Gomptes Rendus of August 12th, 1872, recommended the insertion of the memoir in fall, in the Memoires des Savants Etrangers, which recommendation was adopted by the academy; but M. Grand' Eury continued and enlarged his work by new discoveries, so that it did not appear until 1877. Soon after it was published it received one of the gold medals from the general union of learned societies. While adopting most of the conclusions of Ginetz, Brongniart and Gruner, his systematic botanical and geological classifications and divisions have greatly enlarged our knowledge of the French carboniferous flora, and his work is one of the most valuable contributions to vegetable pal~eontology which has appeared for many years. C. The Giffard B a l l o o n . - - T h e captive balloon for the Universal Exposition is nearly completed. It has a capacity of 25,000 cubic metres, and a diameter of 86 metres. The bag is made of alternate sheets of calico and caoutchouc, and is supposed to be impermeable to hydrogen. It will be inflated with pure hydrogen, prepared on the spot from iron filings and sulphuric acid. It will be able to raise fifty persons to a height of more than 500 metres.--Zes Mondes. C.