WITH NOTES. 457 



ebbing you take out the Globe, the 

 water of that Veflel prefently return- 

 eth to flow, and never ebbeth after, 

 until 5 the Globe be returned into it, 

 and then the motion beginneth as 

 before. 



5 unless for until. 



[A constant Water-flowing and ebbing motion. ] We 

 are very much mistaken if this is not the result of one 

 of the Marquis s early experimental model demonstra 

 tions, and a happy illustrative example for the lecture- 

 table of raising water by the condensation of steam. 



A, B ? represents two water tanks or cisterns, perma 

 nently connected by the water-pipe C, and having 

 within, D, D, two perforated shelves or false bottoms ; 



E, is a main steam-pipe, with a four-way steam cock at 



F, branching into the form shown at G, G , and pass 

 ing through the bottom of each tank, rises vertically to 

 the level of the false bottoms, where each is supplied 

 with a valve at the top end, to prevent the ingress of 

 water. G , is shown receiving steam from E. H, I, are 

 two hollow metal globes, surmounted with a small 

 crown ornament to conceal a spring valve, to which 

 a floating weight is suspended by a chain, as at X ; 

 but floated upwards at X, where it operates to open 

 the spring valve within the crown. In the above 



