120 Some Observations on Sleam- Engines. 



quired to perform a given quantity of work. Of this improve- 

 ment w& shall give some account in the article immediately fol- 

 lowing. 



XXV. Specification of Mr. Arthur Woolf's latest Patent for 

 certain Improvements in the Constructiun and IVorking of 

 Steam- Engines. 



"t 



JL THE said Arthur WooLF do herebvdescrihe and ascertain the 

 nature of my said invention, and the manner in which the same 

 is to be performed, as follows ; that is to sav : the working cylinder 

 of mv said steam-engine has no bottom, but is inclosed in another 

 cylinder, of such dimensions that the space between the two (which 

 space I call the receiver) is equal to at least the contents of the 

 working cylinder. The inclosing cvlinder has a bottom, and the 

 two cylinders are joined together at the top l)y flanches, or any 

 other suitable means ; and the lower rim of the working cylin- 

 der is about as far distant from the bottom of the inclosing cy- 

 linder as the distance between the sides of the two cylinders. 

 (N. B. Though I have called the inclosing vessel a cylinder, it 

 may be of any other figure fit to receive the working cylinder, as 

 will be rendered sufficiently obvious by explaining my mode of 

 working, which is as follows.) Instead of having a void space 

 for receiving steam below the piston, or whatever may be used 

 instead of a piston, I introduce below it, and into the receiver, 

 such a quantity of oil, fat of animals, wax, or any other substance 

 not too volatile, and which may be kept fluid by such a tem- 

 perature as may conveniently be commanded, as shall, when the 

 piston is at its greatest height in the working cylinder, fill all the 

 space below it, and also fill the receiver up to the height of a 

 few inches above the lower rim of the working cylinder. Things 

 being thus arranged, if the engine is to be worked by the pressure 

 of the atmosphere, the receiver has a communication with the 

 boiler. This com.munication being opened, steam is admitted 

 into and fills the receiver above the oil, or other fluid body. If 

 the communication between the receiver and the boiler be now 

 shut off, (by any of the means in common use, or by any other 

 means,) and a communication be opened from the receiver to 

 the condenser, (previously exhausted by the usual means,) a va- 

 cuum will be formed in the receiver, and then the pressure of 

 the atmosphere, acting rqjon the piston, will cause it to descend 

 in the working cylinder, pushing the oil or other fluid t)ody be- 

 fore it, and causing rhe fluid body to ascend into the receiver, 

 after which the steam is again admitted for the next stroke. If 

 the engine, instead of being worked by the pressure of the at- 

 mosphere. 



