190 THE MINERS FRIEND. 



that is but losing so much strength) and is easily prevented, 

 by pulling the Regulator some littU time before the Veuel 

 forcing is quite emptied. This being done, immediately turn 

 the Coclc or Pipe of the Cistern X on P N° (1.) so that 

 the Water proceeding from X through Y (which is never 

 open, but when Turned on P N° (1.) or P N° 2. but when 

 between them, is tight and stanch) I say, the Water falling 

 on P N° (1.) causes by its Coolness the Steam (which had 

 such great force just before) to its Elastick power, to Con- 

 dence, and become a Vacuum^ or empty Space. So that the 

 Vessel P N° (1.) is by the External Pressure of the Atmos- 

 phere, or what is vulgarly called Suction, immediately 

 Refilled, while P N° (i2.) is emptying ; which being done, you 

 push the Handle of the Regulator from you, and throw the 

 Force on P N° (1.) pulling the Condensing Pipe over P N° 2. 

 causing the Steam in that Vessel to Condense, so that it Fills 

 while the other Empties. The labour of Turning these two 

 parts of the Engine, vi%. the Regulator and Water- Cock, and 

 Tending the Fire, being no more than what a Boys strength 

 can perform for a day together, and is as easily learn'd as 

 their driving of a Horse in a Tub- Gin: Yet, after all, I 

 would have Men, and those too the most apprehensive, 

 imployed in working of the Engine, supposing them more 

 careful than Boys. The difference of this Charge is not to 

 be mention'd, or accounted of, when we consider the vast 

 Profit which those who use the Engine will Reap by it. 



The Ingenious Reader will probably here Object, That the 

 Steam, being the Oaufe of this Motion and Porce, and that 

 Steam is but Water Rarified, the Boyler L must in some 

 certain time be emptied, so as the work of the Engine must 

 stop to replenish the Boyler, or indanger the Burning out, or 

 Melting the bottom of the Boyler. 



To Answer which, please to observe the Use of the small 

 Boyler D. When it is thought fit by the Person tending 

 the Engine to Replenish the great Boyler (which requires an 

 hour and half, or two hours time to the sinking one foot of 

 Water) then, I say, by turning the Cock of the small Boyler 

 E, you cut off all Communication between aS the great Force- 

 Pipe, and I) the small Boyler, by which means D grows 



