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FOREIGN AND MISCELLANEOUS INTELLIGENCE. 

 I. MECHANICAL SCIENCE. 



1. ON THE DISCHARGE OP A JET OF WATER UNDER WATER. 

 (R. W. Fox, Esq.) 



THE following letter is addressed to tlie Editors of the Philosophical 

 Magazine. 



* I am not aware that it has been before noticed, that a jet of 

 water discharges the same quantity, in water, as in air, in a given 

 time, without reference to the depth or the motion of the water, 

 at least within certain limits. Thus when the experiment was tried 

 with a head of water six feet high, the same orifice discharged equal 

 quantities in equal times, in air, in still water, and in a rapid stream, 

 moving at the rate of about six feet in a second ; the jet having in 

 one case been turned with the current, and in another against it: and 

 when, by lengthening the-tube, the aperture was submerged to the 

 depth of fifteen feet, the effect was the same as at the surface, under 

 the pressure of an equal column above it. These results have been 

 obtained by my brother Alfred Fox and myself, and you may per- 

 haps think them deserving a place in your Magazine, if they should 

 appear to you to be new. 



* We sometimes coloured the water, when the jet appeared to pass 

 unbroken to a considerable distance under the water*.' 



2. ON PREVENTING THE DISCHARGE OP A BULLET FROM A GUN 



BY THE FINGER. 



At the sitting of the Helvetic Society of Natural Sciences of the 

 28th July last, a letter was read from Dr. Flachin of Yverdun, 

 relative to an experiment before mentioned to the society, in which 

 the ball was prevented from leaving the bottom of a musket when 

 the gunpowder was fired, simply by putting the ramrod upon the ball, 

 and the end of the finger upon the ramrod. He supposes the effect 

 may be explained by the circumstance, that near the charge the ball 

 has a very small velocity compared to that impressed upon it by the 

 expansive force of the gases from the fired gunpowder, when exerted 

 during the whole of the time in which it is passing along the barrel. 

 It is well known that the effect thus accumulated is the reason why 

 long pieces carry further than short ones, and why the breath of a 

 man, which cannot exert a pressure of more than a quarter of an 

 atmosphere, may, by means of a tube, throw a ball to the distance of 

 sixty steps. The experiment above requires great care, especially as 

 to the strength of the piece, which is very liable to burst in the per- 

 formance of the experiment f. 



Vol. viii, p. 342, t Bib, u fr. ; 1830, p, 447 





