-48 WATER BLOWING MACHINE. 



XI. 



Experiments made -with the Water blowing Machines of the Iron 

 Works of Poullaouen ; by Citizens Beaunier and Gallois , 

 Mine- Engineers *. 



Theetpen- OuR objeft was to ascertain the differences in denfity of 



ments made to ,..,.,, . J 



&ewthe eft'efts the air within a blowing machine, under the various circum- 

 of a blowing fiances by which it might be affected; and at the fame time, 

 we 1 endeavoured to find what may be the moft advantageous 

 mode of conftrucling the maehine, to produce the greatefl 

 effect with the lead expenditure of water. 

 Former accounts One of the chief caufes of the doubts that have arifen re- 

 are obicurc fpecling the fuppreflion or retaining of certain arrangements 

 in the conftruclion, was the omitting to defcribe the machines, 

 the experiments with which have been compared. We fhaU 

 therefore previoufiy notice the principal diftin&ions that may 

 be made between thefe machines, from the manner in which 

 their effect is produced. 

 Two kinds of Dr- Lewis obferves, that there are two general methods of 

 water blowing caufing the air to be conveyed by the water in the blowing: 



engines, as the , . T , _ , J . . ° 



air is received machines. In the nrtr, the water receives the air by the 



autop, or from fummit of the machine; in the fecond it receives it by lateral 



apertures : and he lays it down as a principle, that thole 



circumftances, which promote the effect in the one cafe, are 



detrimental to it in the other. 



General ob- **e Stewed further, that if the water be at reft in the 



fervations of funnel of the machine, (fee Plate III. Fig. 2.) and afterward 



The engine is ^ave hbertv to run off > it carries little or no air with it ; that 



an upright pipe if the water have a gyratory motion in the funnel, it carries 



t Jhoic h r of iCh down a conruierable quantity ; and that if it fall from a cer- 



water and air tain height, fo as to have been greatly divided, it carries ffill 



defended. more . tha( jf the water fl ow through a pipe with lateral 



apertures, it receives air through thefe apertures, even when 



its motion is flow : that if the pipe be of equal diameter 



throughout, the quantity of air thus received is inconfiderable ; 



Lateral apertures but if the diameter be diminiflied to a certain degree at the 



admitdr!* the part wbere the a P ertures are made, the quantity of air is 



air. greater than could have been introduced through the funnel 



* Tranflated from the Journal des Mines, No, 91, 



without 



