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Shaw's gunpowder pile-driver
274
_Electricity of the Torpedo.
[.}'our.Frank. Inst.,
unnecessary illustration by a curve, which, I think, has rather contributed to obscure the subject. For the remaining part I am indebted principally to Chauvenet's Least Squares, and Fischer's Geodesy. Whatever is not found in these three authors I claim as original.
Electricity of the Torpedo.--M. Marcy was led, by some experiments which he made in !871, to investigate the relations between the voluntary electric discharge of the torpedo and the voluntary muscular contractions of animals. By the aid of M. Marcel Deprez's electro-magnetic signal, which is able to register more than 600 successive electric currents per second, he found that the torpedo shock is a complex act, formed of successive currents, which follow each other at very short intervals, commonly ranging between ~ and ~ of a second. The effects of gradual fatigue upon the discharges, the varying intensity of the current, the correspondence between primary and induced currents, and the analogy to the series of efforts which produce ordinary muscular contraction, are all illustrated by M. Marey's diagr~ms.--C. R., Jan. 22. C. The C a v e - D w e l l e r s . - - D r . Mitchell, of Edinburgh, places the cave-man in the bone rather than in the stone age. His weapons were made of bone or horn, and highly finished, while his stone implements were extremely rude. The art faculty and the cranial developments of the cave people, show that they possessed a high capacity for culture.--_hrature. C.
Objection to the Algerian Sea,--In a letter to M. Daubrde, M. Naudin states his fears that if the shallow Algerian chotts are filled with water, they will form an immense pestilential breeding place, worse than the Tuscan Maremma or the Pontine Marshes. The greatest depth in the centre of the basin would not exceed 25 metres, and over most of the surface the water would be very shallow. All the conditions would be favorable to an immense multiplication of organic life, decay and miasm.--Gomptes Rendua. C. S h a w ' s Gunpowder P i l e - D r i v e r . - - M . Lavoinne gives a detailed account of Shaw's pile-driver, as improved by Prindle, with calculations of the work done : 1, till the moment of explosion ; 2, at the instant of explosion; 3, during the ascent of the ram.--Ann, des _Ponts et CIr. C.
_Electricity of the Torpedo.
[.}'our.Frank. Inst.,
unnecessary illustration by a curve, which, I think, has rather contributed to obscure the subject. For the remaining part I am indebted principally to Chauvenet's Least Squares, and Fischer's Geodesy. Whatever is not found in these three authors I claim as original.
Electricity of the Torpedo.--M. Marcy was led, by some experiments which he made in !871, to investigate the relations between the voluntary electric discharge of the torpedo and the voluntary muscular contractions of animals. By the aid of M. Marcel Deprez's electro-magnetic signal, which is able to register more than 600 successive electric currents per second, he found that the torpedo shock is a complex act, formed of successive currents, which follow each other at very short intervals, commonly ranging between ~ and ~ of a second. The effects of gradual fatigue upon the discharges, the varying intensity of the current, the correspondence between primary and induced currents, and the analogy to the series of efforts which produce ordinary muscular contraction, are all illustrated by M. Marey's diagr~ms.--C. R., Jan. 22. C. The C a v e - D w e l l e r s . - - D r . Mitchell, of Edinburgh, places the cave-man in the bone rather than in the stone age. His weapons were made of bone or horn, and highly finished, while his stone implements were extremely rude. The art faculty and the cranial developments of the cave people, show that they possessed a high capacity for culture.--_hrature. C.
Objection to the Algerian Sea,--In a letter to M. Daubrde, M. Naudin states his fears that if the shallow Algerian chotts are filled with water, they will form an immense pestilential breeding place, worse than the Tuscan Maremma or the Pontine Marshes. The greatest depth in the centre of the basin would not exceed 25 metres, and over most of the surface the water would be very shallow. All the conditions would be favorable to an immense multiplication of organic life, decay and miasm.--Gomptes Rendua. C. S h a w ' s Gunpowder P i l e - D r i v e r . - - M . Lavoinne gives a detailed account of Shaw's pile-driver, as improved by Prindle, with calculations of the work done : 1, till the moment of explosion ; 2, at the instant of explosion; 3, during the ascent of the ram.--Ann, des _Ponts et CIr. C.