WITH NOTES. 525 



possesses no locomotive power, being restrained to one 

 spot by a strong pillar underneath, working at the 

 centre in a cup-and-ball joint, so that it can fall 

 sideways, backwards, or forwards, unless prevented by 

 equestrian skill ; it was, however, more than master of 

 the greater number of many excellent horsemen who 

 subjected themselves to its astonishing gambols. 



The Marquis s automaton was possibly intended for 

 a kind of circus, and we may suppose that a strong post 

 being in the centre, a long wooden bar was so placed 

 across it as to revolve with the horse attached to one 

 end, and a weight or counterpoise on the other ex 

 tremity, motion being given to the horse s legs by 

 internal machinery, and acting to propel it so long as 

 the rider pleased, or the mechanism permitted. 



I 9 2 - 



A fcrue made like a Water-scrue, 

 but the bottom made of Iron-plate 

 Spade-wife, which at the fide of a 

 Boat emptieth the mud of a Pond, 

 or raifeth Gravel. 



[A Gravel Engine. ] The principle of the modern 

 dredging machine is to be seen in Besson s &quot; Theatrum 

 Instrumentorum et Machinarum,&quot; 1578, where about 

 25 hampers or buckets are attached to two endless 

 chains passing over two drums, one at the bottom of 

 two strong inclined poles, the other at the top of the 

 same, where a workman turns it by means of an ordinary 

 winch applied to an endless screw; while labourers 

 below are actively filling the ascending vessels. The 

 Marquis may have had in view to make each bucket 

 dig up its own supply of gravel, &c. as indeed is the 

 present practice. 



This antiquated dredging machine, in some other 



