OF COMPRESSED AIR. 225 



adherence of the air-valve was observed by 

 Mr. Roberts, he ascertained, by experiment, 

 without knowing that it had been done before, 

 that water, when forced through a conical pipe, with 

 considerable velocity, will draw out other water, 

 placed below in an open vessel, if one end of a 

 small tube is inserted in the conical pipe, and the 

 other end is immersed in the water, in the vessel 

 below : thus shewing that water, an inelastic 

 fluid, produced the same effect that air did, 

 when rushing out in a stream, confined in a pe- 

 culiar manner. And at the time this paper was 

 going to press, water was, by pressure from a 

 column of considerable height, made to issue 

 from a pipe vnth a valve placed over it, similar 

 to what is exhibited in Fig. the 1st, when the 

 valve, instead of being forced off by the issuing 

 stream of water, was found to adhere to the seat, 

 at a small distance from it. And when the ap- 

 paratus was inverted, and the valve consequently 

 placed below the seat, upon the water being 

 permitted to flow, the valve, instead of obeying 

 the law of gravity and falling by its own weight, 

 or of being driven ofl' by the force of the stream 

 of water, adhered, with considerable firmness, 

 to the seat. 



2r 



