MicroOGRAPHIA. 
found Room in this Plate to have inferted an O you fhould have feen that _ . 
the /etters were not more diftin& then the points of Diftin@ion, nora 
drawn vircle more exactly fo,then we have now fhown'a poixt to be'a point. 
Obferv, 11. Ofthe Edge of a Razor. 
Schem.2. #™ He fharpeft Edge hath the fame hind of affinity to the fharpeft Point 
Fig. 2. 
_ fince Putte, or even the moft curious P that can be made ufe of, to ] 
4 
on a 
* moft 
> in Phyficks, as a Jive hath to a point in Mathematicks’; and therefore 
the Treaty concerning ‘this, may very properly be annexed ‘to the for- 
mer..A Razor doth appear to be a Body of a very neat and ‘curious a- 
fpect, till more clofely viewed by the Adicrofcope, and there we may ob- 
ferve.its very Edge to be of all kind of fhapes, except what ‘it: fhould be: 
For examining that of a very fharp one, I could not find that any part of 
it had any thing of tharpnefs in it; but it appear'da rough furface of a — 
very confiderable bredth from fide to fide, the narroweft part not feem- 
ing thinner then the back of a pretty thick Knife. Nor is't likely that it 
fhould appear any otherwife, fince as we juft now fhew'd that a pont ap- 
pear d a circle, tis rational a line fhould bea parallelogram. 
Now for the drawing this fecond Figure(which reprefentsa part ofthe _ 
| Edge about halfa net of aninch long of aRazor wellfet) Hfoplacdie 
between the Obj ame & the light.that there appear'd a reflection from 
the very Rapesepe 
perceive it to be fomewhat {harper then elfewhere about d, to be indent- 
. 5 dee ate 
vies aa Sti ees 
{ented by the white line #bc def. In which youmay 
ed or pitted about b, to be broader and thicker-about ¢, and unequal — 
and 
part 
imamaseboo: e, and pretty even between a b and ef. Nor was that 4 
of the Edge ¢ 474 fo {mooth as one would imagine fo fmooth be- 
dies asa Hone and Oy] fhould leave.it ; for befides thofe multitudes of ; 
feratches, which appear to have raz'd the furface g hz k, and to crols = 
each other every way which are not half of them expreft in the Figure, 
there were feveral great and deep fcratches, or furrows, fuch as g 4 and 
2k, which made the furface yet more rugged, caus’ perhaps by fome 
fmall Duft cafually falling on the Hone, or fome harder or more Hinty — 
part of the Hone it felf: The other part of the Razor 71, whichis polifhd 
_Glafies for A4icrofcopes, and other Optical ufes; P have, when the Sun has 
. fhone well on them, difcover'd their furface to be varioully raz’d-or 
fcratched ,and to confift of an infinite of {mall broken furfaces, which re- 
flece the light of very various and differing colours. And indeed it feems 
impoflible by Art to'cut the furface of any hard and brittle body fmooth, 
polith fuch a body, muft confift of little hard rough particles, and each of 
_ them muft cut its way, and confequently leave fome kind of gutter or 
Ae Sar ee. furrows 4 
Sendos tex, appear’d much rougher then the other, lopking al- — 
ea plow field, with many parallels, ridges, and furrows, anda 
cloddy,.as twere, or an uneven furface : nor ‘fhall we wonder ‘at the — 
roughnefles of thofe. furfaces, fince even in the moft curious wrought 
