C 33 3 
Notions of the Stru&ure and Power of a diflra&ilc 
Fibre. He fnppofes the Parts of a diftraftile Fibre to 
be made up of certain MachinuU , like Syringes and 
their Embolus’s , and their Motion to be analogous 
to that of the Inflrument mention’d. “ The Obfer- 
<{ vations and Experiments (fays he) which have been 
cc made of late, but more particularly by Mr. Boyle , 
about the Spring of the Air, have explained to us 
cc the Contrivances and Properties of a Syringe ; and 
tc the Reafons upon which that Phenomenon of the 
“ Difficulty of drawing back the Embolus , when the 
“ Pipe is flopped, depends ; and the Neceffity of any 
<c Liquor’s following it, wherein the Pipe is im- 
<c merfed : The Reafon of which being well confi- 
“ dered, it will be found, that all which is neceffary 
te for this Contrivance is, that the Embolus be fa» 
l( exa&ly adapted to the inner Surface of the Barrel, 
“ as to prevent any Air paffing between them when 
fc it is drawn up; and that it matters not what Figure 
the Barrel is of, fo that the Embolus is well fitted to 
“ it. It eafily therefore might be contrived to make 
cc a Cafe of Syringes, wherein every Barrel may 
Cf alfo ferve as an Embolus to its Exterior, which 
“ immediately includes it. And, with this View, it 
“ is not at all difficult to imagine a continued Series 
“ of Particles fo put together, that the inner may 
“ be moved and drawn upon one another, without 
“ fuffering the Air immediately to enter into the In- 
“ terftices made by their Diflra&ion : Whereupon, 
<c as foon as that Force which drew them is removed, 
‘ f they will, for the very fame Reafon as the Embo- 
“ lus of a Syringe , rufh up again into their former 
<c Conta&s.” This is his Notion of the Arrange- 
F ment 
