HYDRODYNAMICS. 



501 



-*"** The following Table contains Eytelwein's co-efficients height is 8.04, and the diminished velocity arising from Discharge 

 or Water f^ different cases connected with those which belong contraction is shewn in the last column. '** 



/fri^f 1 . to the present section. The whole velocity due to the additional 



Tubes. 



TABLE VII. Containing Eylelifein's Co-efficients for Orifices of different kinds. 



Eytelwein's 

 Table of co- 

 efficients. 



S'tcr. IV. On the Quanlitirt of Water discharged from 

 result kept constantly full, by additional Tutei adapt- 

 ed to circular Orijues. 



IT was observed, even by Julius Frontinus, that 

 short tube inserted into an orifice, produced a greater 

 discharge of fluid than would have been obtained by a 

 simple orifice of the wine area. Ouglielmini noticed 

 the same fact, and explained it by an augmentation in 

 the weight of the atmosphere. He regarded the velocity 

 at the end CQ. ( Fig. 6.} of the tube BOQC, a* that which 

 is due to the whole Height AC, upon the erroneous 

 supposition that the pressure at C it the same in a state 

 of notion a* in a state of rest. Guglielmini did not 

 consider the diminution of discharge arising from the 

 friction of the same ratface of the tube BCXjC, nor the 

 augmentation of discharge arising from the form of 

 the tube, and, by a singular concurrence, these errors 

 mutually compensated each other in his experiments. 



M. liariotte comiders the water as issuing at ( (}. 

 with a velocity which is a mean proportional between 

 the velocities due to the heights AB and AC. Daniel 

 Bernoulli explained the increased expenditure from addi- 

 tional tubes, by the theory of the conservation of living 

 forces; and Euler and d'Alembertt wen of opinion, 

 that the pressure of the atmosphere were concerned in 

 jduction of the effect. It was reserved, however, 

 fur Yenturi, as we have already seen in the preceding 

 chapter, to explain the phenomenon in the most satis- 

 factory manner. Before we {proceed to give an account 

 of his experiments, we shall lay beiore our readers a 

 full view of the experiments of M. Bossut. 



M. Bossut inserted in the bottom CD (Fig. 10.) of the 

 icl tube M n op made of cop- 

 per, well polished within: it was two inches in diameter, 

 and two inches long. Having stopped th.- aperture M n 

 '-ant of a cork, and filled the reservoir with water 

 to th< ,., 10 lines above M , be 



**""!. "I t c-ork, that the water did not 



Jblluw the tide* of the tube, but that the vein was con- 



tracted as in a simple orifice, and could not be made to Bosrat'i ex. 

 fill the tube without giving it a greater weight. He pemmnu. 

 therefore took a cylinder m n o p, 1 inch in diameter, 

 and "2 inches long, in which the water readily filled 

 the tube. In repenting these experiments, however, 

 he thought of stopping the discharge within the re- 

 servoir, instead of without, by means of a circular plate 

 M, covered with felt, and placed at the end of a handle 

 pon withdrawing the plate M, he was surprised 

 to find that the water sometimes followed the sides of 

 the tube, and sometimes refused to follow them ; and 

 he was at Ust able to produce th.- effect at pleasure, 

 even when the length of the tube was reduced fruni 

 J incites.. to 1 inch and 6 lines. \Vhrn tin- length of 

 the tube was reduced to half an inch, he could never suc- 

 ceed in making the water touch its sides. Between 

 the interval of half an inch and I .} inches, it is not easy 

 to observe what takes place with certainty. 



The following Table shewn the results which M. 

 Bossut obtained. 



TADLB VIII. Containing the Quantities of Water dis- 

 charged by Cylindrical Tubes one inck in diameter 

 and of dijfirrnt lengths, nhelhtr Ike Tubes were in- 

 tttlcd in the bottom or in the tides of the eessel. 



These results clearly prove, that the expenditure in- 

 creases with the length of the tube, and that the quan- 

 tities of fluid discharged are nearly as the square roots 



:i* pouilo babet momentum. *i in rrctum M ad Isbram collotatu* *t ; modum *srrt et ad curium squat n oppoiitu. 

 LM ryit ; ad Istu* autcm pretrmuitii aquai eontcreu* et lupinut, Dec sd bMUlum proniu: Kcnitcr iijuou.4'ie 

 r rontui'i* ttr jtjiafJiKtHiu L'rUt Hum*, lib. i juita Bn. 

 t att O'Alcmbrn Tnutc dt CKjmUtrt tt dm mtntmoU <Ut ftiuda, f lt. 



