378 JAMES WATT. 
the machine constructed by that engineer in 1698, to that 
of his predecessors, although he introduced some essential 
modifications into it; that, amongst others, of generating 
the steam in a separate vessel. Although it may signify 
little relative to principle whether the steam be generated 
from the same water that is to be elevated and in the 
same caldron where it is to act, or from a separate vessel 
to be admitted at will through a tube of communication 
furnished with a tap above the fluid that is to be expelled, 
it is not so in practice. Another alteration, still more 
useful and worthy of special mention, equally due to Sa- 
very, will be more appropriately treated of in the article 
that we shall devote in the sequel to the labours of Papin 
and Newcomen. 
Savery had entitled his work The Miner’s Friend. 
But the miners did not show themselves sensible of 
his politeness. With only one exception, none of them 
ordered his machine. ‘They have been used only to dis- 
tribute water through various parts of palaces and coun- 
try houses, parks and gardens; recourse has been had to 
them only to overcome a difference of levels of twelve or 
fifteen metres. We must keep in mind, however, that 
the danger of explosion would have been very great, if 
the immense power had been given to this apparatus 
that the inventor asserted they could bear. 
Marquis of Worcester did actually make an “apparatus’’ to drive 
water up by fire; and Cosmo de Medici, Grand Duke of Tuscany, de- 
scribes in his Diary that he saw it in operation at Vauxhall, in the ~ 
year 1656,—“ went beyond the palace of the Archbishop of Canter- 
bury, to see an hydraulic machine invented by my Lord Somerset, 
Marquis of Worcester. It raises water more than forty geometrical 
feet by the power of one man only; and in a very short space of time 
will draw up four vessels of water through a tube or channel not more 
than a span in width.” Savery’s engine was an improvement upon 
this by the introduction of a vacuum.— Translator. 
