Water-pipes and Syphons from disengaged Air, <J-c. Ill 



posed to lodge, being that part of the pipe which has the small- 

 est degree of inclination (Fig. 3.) ; then, as in the case of the 

 syphon, to shut the stopcocks at B and at^ and open the stop- 

 cock e, when the air which has accumulated from the pipe into 

 the lower cylinder will escape, and the water in the upper vessel 

 descend to occupy its place. Then the valve e is to be shut, 

 andy and B to be opened, and the . upper cylinder again filled 

 with water until the operation requires to be repeated. In wa- 

 ter-pipes these operations must be performed by the hand of the 

 person in charge of them ; but, in the case of the syphon, a self- 

 acting power may easily be given to it, which will work the valves 

 at intervals without the necessity of attendance. 



It now only remains to describe a certain case or class of si- 

 tuations in which the air-extractor may be applied to a purpose 

 of some importance. Suppose the house H, (Fig. 4.), is so 

 situate as to be unable to obtain a spontaneous supply of water,^ 

 but that a constant spring B is discovered on the opposite side 

 of a hill or long ridge of high land A, the lowest point C of 

 whose summit is thirty feet higher than the spring. No doubt 

 if a pipe were laid from the well over this lowest summit to the 

 house, the water would, on the air being extracted from the 

 pipe, flow to the house, the pipe acting as a syphon. But the 

 accumulation of disengaged air would in a very short time create 

 such an obstruction as could not be removed by any of the 

 means at present in use ; and, if ever attempted, it would pro- 

 bably be abandoned as hopeless. This, however, is a case to 

 which I apprehend the air-extractor might be applied with a 

 certainty of success ; and it is in situations of this kind that I 

 think it especially calculated to be of practical utility : for I 

 am persuaded that many fine springs of water, which at present 

 would be considered as utterly inaccessible, might, by this means, 

 with ease and certainty, be commanded and applied to useful 

 purposes. Nay, by employing several pipes or syphons of large 

 size, and uniting their vertices by connecting-pipes with one 

 common air-extractor, a supply of water, in larger quantities, 

 miglit be obtained from springs or rivulets in similar situations, 

 for irrigation, machinery, bleaching, and other purposes, when 

 unattainable by ordinary means. 



CoLQUHALZiE, 2d December 1833. 



