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Hooke, Robert, 1635-1703 / Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses : with observations and inquiries thereupon
(MDCLXVII [1667])

Observ. XVI. Of charcoal, or burnt vegetables,   pp. 100-106 ff.

Page 100

D            MICROGR AP H IA.
which we think the moft folid ones, and appear fo to our fight, have not-
withfianding abundance of thofe groficr kind of pores, which will ad-
mit feveral kinds of liquors into them, why thould we not believe that
Glafs, and all other tranfparent bodies abound with them, fince we have
many other arguments, befides the propagation of light, which feemto
argue for it ?
   And whereas it maybe obje&ed, that the propagation of light is no
argument that there are thofe atomical pores in glafs, fince there are Hy-
pothefes plaufible enough to folve thofe Phenomwena, by fuppofing the
pulfe onely to be communicated through the tranlparent body.
   To this I anfwer, that that Hypothejis which the induftrious Aforeanw
has publifh d about the flower motion of the end of a Ray in a denfer
medium,then in a more rare and thin~feems altogether unfufficient to folve
abundance of 'henomena, of which this is not the leaft confiderable,that
it is impoffible from that fuppofition, that any colours fhould be gene-
rated from the refra&ion of the Rays ; for (ince by that Hypothefis the
undulating pude is always carried perpendicular, or at right angles with
the Ray or Line of direCfion, it follows, that the ftroke of the pulfe of
light, after it has been once or twice refracted (through a Prifmefor ex-
ample) muft affect the eye with the fame kind of ftroke as if it had not
been refracted at all. Nor will it be enough for a Defendant of that HI-
pothefis, to fay, that perhaps it is becaufe the refraffions have made the
Rays more weak, for if fo, then two refraftions in the two parallel fides
of a uadrangular Pr#Jre would produce colours, but we have no fuch
Phienomena produc'd.
    There are feveral Arguments that I could bring to evince that there
 are in all tranfparent bodies fuch atomical pores. And that there is fuch
 a fluid body as I am arguing for, which is the medium, or Inftrument, by
 which the pulfe of Light is convey'd from the lrcid body to the en-
 lightn'd. but that it being a digreffion from the Obfervations I was re-
 cording) about the Pores of Kettering Stone, it would be too much fuch,
 if I fliould protract it too long ; and therefore I fhall proceed to the
 next OIflersation.
        Obferv. X VI.    Of Charcoal, or burnt Vegetables.
 (~Harcoal,or a Vegetable burnt black,affords an obje&:no lefs pleafant
 Cg than iniftruftive  for if you take a fimall round Charcoal,and break
 it thort with your fingers, you may perceive it to break with a very
 fmooth and fleck furiace, almofi like the furface of black fealing Wax ;
 this furface, if it be look'd on with an ordinary Zkicrofcope, does manifeft
 abundance ofthofe pores which are alfo vifible to the eye in many kinds
 of wood, rang'd round the pith, both a in kind of circular order, and a
 radiant one. Of thefe there are a multitude in the fUbflance of the Coal,
 every where almoft perforating and drilling, it from end to end ; by

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