WITH NOTES. 451 



oiled paper, because it is more lasting&quot; when employed 

 for windows. 



55- 



A double Water-feme, the inner- 

 moft to mount the water, and the 

 outermoft for it to defcend more in 

 number of threds, and consequently 

 in quantity of water, though much 

 fhorter then the innermoft fcrue, 

 by which the water afcendeth, a 

 moft extraordinary help for the 

 turning of the fcrue to make the 

 water rife. 



[A double Water-scrue.~] The arrangement of this 

 simple invention is so clearly and amply set forth, that 

 it is a wonder it could ever have been misunderstood ; 

 yet it so baffled Mr. Partington, that he classes it among 

 &quot; extraordinary sleight of hand discoveries.&quot; 



M. Pattu, a French engineer, in 1815, published his 

 account of a double water-screw of this description 

 which he had invented, capable of being applied in 

 three different ways, the construction, however, in all 

 being the same. In one arrangement, the enlarged end 

 of the screw is about one-eighth part that of the entire 

 length of the internal or lesser screw, and it surrounds 

 the &quot; innermost&quot; screw, the spirals winding in a reversed 

 direction. The top of the shorter or &quot; outermost&quot; screw 

 may be on a level with a stream of water &quot; for it to 

 descend&quot; therein, to promote &quot; the turning of the screw&quot; 

 (of greater length and smaller diameter) &quot; to make the 

 water rise,&quot; from a lower stream. 



2 G2 



