ijS Lateral Motion of Fluids, '^Overftwing Well. 



It is true, that by prolonging the tube C D FE to the length of 204 lines Jn the horizon- 

 tal pofition, the four cubic feet flowed out in 19". But to obtain this effe£l, i found it ne- . 

 cefTary to fix a prominence within the tube at O, which forced the fluid to fly upwards, 

 and by that means to fill the whole tube. 



Experiment XVII. In this experiment the horizontal tube CD FE, fig. 11, was mora 

 (Tivergent'than in the foregoing trials. It was 117 lines long, and 36 lines in diameter at 

 E F. The reft of the apparatus was the fame as before. The expenditure was made 

 in 28''i the ftream did not fill the whole fedlion E F. The refult was the fame when fuc-^ 

 cefllve portions of the pipe were cut off, until CE was no longer than ao lines, and the 

 external diameter 18 lines. In this cafe the ftream filled the pipe, and lUe expenditure was 

 alfo made in 28". 



When the length C E was 20 lines, its external diameter EF was increafed to 20 lines^ 

 In this cafe the ftream was detached from the fides of the tube, and the expence of four 

 feet took place in 42 feconds, as in the Vlth experiment. 



»Thefe experiments teach us, that by varying the divergence of the fides of tubes, the 

 lateral communication of motion has a minimum and a maximum of efFedl. The minimum 

 is feen in the laft experiment. It appears that the lateral comriiunication cejfes t > produce- 

 its efFe£t when the angle made by the fides of the tube with each other exceeds 16 degrees^ 

 The Xlllth experiment nearly determines the maximum of the efFed when the fame angle 

 is about 3 degrees. Thefe limits may alfo, perhaps, in a fmall degree depend upon fomc 



fundion of the velocity. 



[2"o he continued-} 



IX. 



yf« jtccount of the Means employed to obtain an overf owing Well. 

 By Mr. Benjamin Vvlliamy.* 



A E R M I T m^, in compliance with your requefl^, to give you a fhort account of thft 

 well at Norland-houfe, belonging to Mr. L. Vulliamy ; a woric of great labour and expence^ 

 executed entirely under my diredion, and finiftied in November 1794. 



Before I began the work, I confidt red that it would be of infinite advantage fliould a /pring 

 be found ftrong enough to rife over the furface of the well ; and though 1 thought it very 

 improbable, yet I refolved to take from the beginning the fame precautions in doing the 

 work as if I had been aflured that fuch a fpring would be found. But although this very, 

 laborious undertaking has fucceeded beyond my expedtation, yer, from the knowledge L 

 have acquired in the progrefs cf the work, I am of opinion, tliat it will very feldom happen 

 that the water will rife fo high ; nor will people, I believe, in general, bs fo indefatigable as. 

 I'have been in overcoming the various difficulties that did and ever will occur, in bringing^ 

 fuch a work to perfedion. 



In beginning to fink this well, which has a diameter of four feet, the land fpn'ngs were 

 flopped out in the ufual manner, and the well was funk and fteined to the bottom. Whea. 

 the workmen had got to the depth of 236 feet, the water was judged not to be very far oSy, 



• Itt aktter to the Right Honourable Sir Jofeph. Banks,, Ban. K. B. P.R. S. Pliil. Traaf. 1797.. 



