172 Miscellaneous Intelligence. 



water which had passed against the disc was thrown off in a 

 lateral direction all around with a velocity scarcely inferior to 

 that with which it first moved, so that much of the force 

 possessed by the jet of water was not brought into action on the 

 disc, but was expended in the production of this lateral stream; 

 and he concluded, that if in any way this could be accumulat- 

 ed on the disc, the effect would be much greater. To ob- 

 tain, in part, this end, a rim of the height of six lines was 

 raised round the edge of the disc, so as to form it into a kind 

 of dish ; and then, without changing any other circumstance 

 in the experiment, it was repeated. In the first case the power 

 exerted on the disc equalled nine pounds twelve ounces of 

 Milan, now it was increased to twenty poimds. 



These experiments were made with a reservoir of water, ten 

 feet (French) high, having an aperture in its side, near the bot- 

 tom, four inches square ; to this aperture was adapted a pyra- 

 midal canal, which, at its external orifice, was an inch in the 

 side ; so that the section of the stream of water was a square 

 inch, but the length of the canal and the size of the disc, 

 against which the water struck, are not mentioned; the disc 

 was placed vertically at such a distance from the orifice, as to 

 correspond with the maximum of contraction in the jet of 

 water. 



The following table exhibits some other results obtained by 

 this apparatus : the first column expresses the height of the 

 water ; the second, the power exerted on the plain disc ; and 

 the third, the power exerted on the disc with the raised edge. 



6 feet high. 5 Ife. on plain disc. 1 1 fb. on edged disc. 



8 7 ft. 15 lb. 



10 9 m. 20 Jb. 



In consequence of these results M. Morosi objects to the 

 methods generally employed by philosophers to estimate the 

 force of a jet of water, since they do not give half the effect 

 which may be obtained from the same jet by other means. He 

 also thinks that the result observed by the Abbe Zubiani, 

 namely, that a stream of water received on to an iron disk, 

 exerts more force than if received into a wooden one, may be 



