[ 20 ] 
But the Queftion is, How the Pupils are carried to 
the Extremities of the Line? To anfwer this, let us 
confider the State of theMufcles: The tendinous At- 
tachments of the four flrait Mufcles are broad and 
thin, where they are fixed to the Sclerotis 5 fo that 
the Edge of one Expanfion is very near that of the 
other all round the Globe 5 and the flefhy Fibres from- 
them alfo are difpofed in a thin flat Order back- 
wards, until they approach the Bones from whence 
they arife 5 where, for the Convenience of their At- 
tachment, they are fqueez’d clofer together than 
when they firft quit the Globe: From this Pofition 
they may be faid to form a hollow Cone, having' 
the optic Nerve as their Axis . See Tab. II. Fig, 2 ,a* 
XXXII L 
Now, fuppofe the Sight fixed to the Middle of that 
Line above mention d, by the Elevator of each Eye, 
and it was refolv'd to carry it along the Line to the* 
right 5 then the Fibres on the left Side of the Ele - 
vat or of each Eye would remit their Adtions, and 
thofe of the right Side of each Mufcle contrail more 
ftrongly, until they are fucceeded and aflifted by as 
many of the neighbouring Fibres of the AbduEtor of 
the right Eye, and the AdduEtor of the left, as will 
ferve to maintain the View ail along the Line to the 
Extremity on that Side, and vice verfa . 
XXXIV. 
But if a Circle was deferibed in a vertical 
Plane, and it was refolved to carry the Sight 
all 
