WITH NOTES. 545 



he may have experimented on them, there are two 

 things, of which no one has yet given him the credit of 

 possessing any knowledge whatever, the one is, con 

 densation ; the other, a piston. How the Marquis of 

 Worcester could have been experimenting at the cost 

 of 50,000, and upwards, at Vauxhall, and been occu 

 pied in this particular class of experiments during a 

 large portion of thirty-eight years, in perfect ignorance 

 that cold water will condense steam, is past all com 

 prehension. Nay, such ignorance would be a greater 

 matter of surprise, than the exhibition of his utmost 

 ingenuity in the mechanical contrivances connected 

 with his engine. Condensation was no mystery. 

 Every work on distillation spoke on the subject, and 

 supplied the forms of refrigeratory worms, and refrige 

 rating heads for alembics. His very allusion to the 

 strength of his vessels must have had reference, first to 

 internal distension, as well as to collapse from external 

 pressure. 



John Bate, in his first book, &quot; Of Water Works,&quot; 

 describes a kind of weather glass, which he calls, &quot; the 

 moveable perpendicular glass ;&quot; for the construction of 

 which his directions are &quot; First prepare the glass A, 

 B, fill it almost top full of water, provide also the glass 

 K, L, having a loop at the top of it : divide it into so 

 many equal parts as you would have degrees, and on 

 the mouth thereof fasten a thin board, that will easily 

 slip in and out of the bottom glass; make then a 

 weight of lead or brass somewhat heavier than both the 

 glass and board fastened thereunto ; and then tie a 

 little rope to the loop of the glass A, B, and the weight 

 at the other end thereof. Rarifie the air contained in 

 the glass L, and reverse it into the glass A, B, filled 

 with water, and hang the plummet over two little 

 pulleys fastened in a frame made for the purpose ; and 

 as the glass K, L, cooleth, the water will ascend the 



