WATER BLOWING MACHINE. $\ 



pofe. The afflux of water into each was regulated by means 

 of the hatches a and b, and the diftant floodgate Q, placed 

 in the principal channel D. See the plan Fig. I. Plate . 



The anemometer was placed in o, Fig. 2, in the direction 

 of the vertical tube P protracted. The hatch placed in b was 

 let down, fo as to prevent the patTage of the water that way. 

 The hatch placed in a was raifed, and the flow of water re- 

 gulated by means of the floodgate Q. This flow we varied, 

 till we found the water in the graduated tube raifed as high 

 as could be effected without any other change of circumftance. 

 When we were certain we had attained this point, and that 

 no variation in the quantity of water flowing off took place, 

 we made the following obfervations. 



1. The mean depth of the water in C, in the little channel, Obfervations, 

 juft before the T, was 15 inches 6 lines. 



2. The mean depth of the water in the great channel, was 

 18 inches 9 lines. 



3. The water rofe to 26 inches in the graduated tube. The 

 ofcillations varied between 25 and 27 inches, but feldom 

 reached the latter height. 



4. The velocity of the wafer in the great channel having 

 been obferved, the following data were obtained. 



Examined by means of Ample floaters of paper, on an 

 extent of 24 feet, we had, 



lft. The fpace pafled through in two minutes = 61 feet, 

 8 inches, 6 lines. 



2d. The fpace palled through in four minutes = 120 feet, 

 6 inches. 



The fame velocity examined with cork floats, fupporting Method of mea- 

 little balls of wax, the weight of which was augmented by fu j in S the 

 bits of lead, fo that they fwam in the middle of the ftream water. 

 with a gravity little exceeding that of water, we had for a 

 irean of the fpace pafled in two minutes, 63 feet, 7 inches, 

 4 lines. 



If we compare thefe different refults, we (hall find, that 

 the mean velocity of the water may be estimated at 30 feet, 

 4 1 inches, 1 line, a minute : but as it appears to us, that the 

 refults afforded by the cork floats muft approach neareft the 

 truth, we will pay no regard to the quantities before obtained, 

 and eftimate the mean velocity of the water in the greater 

 channel, at 31 feet, 9 inches, 8 lines, a minute, 



E 2 Now 



