[ 3 ?} 3 
to be very fhort, or very near the Point it reds upon, 
and others again on the contrary, where that Extre- 
mity of the Lever ought to be longer, and farther off 
the Point of its Reft, the Bodice of courfe ought to be 
fet backwarder or forwarder, as the End of the Lever is, 
the Dire&ion of which it follows every-where. For 
this Reafon we have contrived Two Rows of Holes 
along the Sides of the Bodice, and between thefe 
Two Sides we got a Notch cut out, to make room 
not only for the Foot, or for the Point it refts upon, 
which may meet there, but alfo for a Part of the 
Lever, which I call its Spur, which always moves 
towards that Notch when the Lever is lowered. The 
Figures and the Ufe of the Machine will fhew the 
Neceflity of this Conftruttion much better than any 
Defcriprion. From the faid Bodice come out Two 
broad Straps of the ftrongeft Leather with their 
Buckles. One of thofe Straps is to go about the Back 
of the Chair, and round the Body of the Patient ; the 
other goes over the Shoulder, very near the Ar- 
ticulation, and keeps the Scapula and the Clavicula 
in their Situation againft the Efforts of the Lever 5 fee 
TAB. II. and IV. 
That Part of my Machine, that may be called the 
Ambe properly faid, is compofed, like that of Hip- 
pocrates , of Two Pieces,- one vertical, which I calf 
the Foot of the Ambe 5 and the other horizontal, 
which forms the Lever. It is chiefly in thefe Two 
Pieces that my Ambe differs from that of Hippo- 
crates. 
The Foot is aPiece made cither of Wood, TAB. III. 
Fig. 2. or of Iron, Fig. 3- Its upper Extremity is 
fplit into a fort of Mortife, which receives the Spur 
E e e 2 or 
