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LXVI. Intelligence and Miscellaneous Articles. 



AIR-PUMP CONSTRUCTED ON A NEW PRINCIPLE. 

 BY M. DELEUIL. 



HPHE machine is intended for industrial purposes, as it is only pur- 

 posed to try to obtain, in a relatively short time, a vacuum 

 of 18millims.of mercury for the size of vessels commonly worked with, 

 and of 8 millims. for the usual sizes of the laboratory. The principle 

 on which I have gone has much analogy with that which guided M. 

 Isoar, ten or twelve years ago, in his superheated steam-engine, 

 which consisted in using steam at high pressures, acting on pistons 

 of small section working with great velocity, and not rubbing against 

 the sides of the cylinder. I imagined that if, in making a vacuum, 

 I caused a metallic piston to move in a cylinder perfectly ; and only 

 leaving between it and the cylinder the thickness of a sheet of letter- 

 paper, the fluid could not pass from one side to the other of the pis- 

 ton, provided that its length was equal to at least twice its diameter, 

 and it was provided with grooves 8 or 10 millims. apart. Expe- 

 riment has shown that with such a piston, without any great ve- 

 locity, a vacuum of from 8 to 18 millims. maybe attained, according 

 to the capacities. The fluid itself serves as packing for the piston. 

 I thus, at the same time, destroy the resistance due to the friction of the 

 piston in the barrel and the stopping up of the valves (by suppressing 

 the oil used to lubricate the pump), as well as the wear and tear of the 

 cylinder. This machine is double-acting, and can be used as com- 

 pression-pump up to the limit of two atmospheres, as it can pump 

 gas from a reservoir, and compress it in another without appreciable 

 loss of gas. — Comptes Rendus, March 20, 1865. 



METEOR AND METEORITES OF ORGUEIL. 



On the evening of the 14th of May, 1864, a very bright fireball 

 was seen in France throughout the whole region from Paris to the 

 Pyrenees. Loud detonations were heard in the neighbourhood of 

 Montauban, and a large number of stones came down near the vil- 

 lages of Orgueil and Nohic. The passage of the meteor was wit- 

 nessed by a large number of intelligent observers, since it occurred 

 early in the evening. Numerous accounts of its appearance have 

 been published in the Comptes Rendus. 



This fall of meteorites is of peculiar interest. While we have over 

 a hundred large fireballs and detonating meteors whose paths through 

 the atmosphere have been computed with more or less precision, 

 there are only four or five of them from which stones have been 

 known to come. Of these four or five, only one, the Weston meteor, 

 has been so well observed that we can speak with confidence of 

 its path. 



