Secondly, it is objected that the explication I give of the appearance of the horizontal moon (which may also be applied to the sun) is the same that Gassendus had given before. I answer, there is indeed mention made of the grossness of the atmosphere in both, but then the methods wherein it is applied to solve the : phenomenon are widely different, as will be evident to whoever ,shall compare what I have said on this subject with the following words of Gassendus. Heinc dici posse videtur: solem humilem oculo speaatum ideo apparere majorem, quam dum altius egreditur, quia dum vicinus est horizonti prolixa est senes vaporum, atque adeo corpusculorum quae solis radios ita retundunt, ut oculus minus conniveat, et pupilla quasi umbrefacta longe magis amplificetur, quam dum sole multum elato rari vapores intercipiuntur, solque ipse ita splendescit, ut pupilla in ipsum speaans contractissima efficiatur. Nempe ex hoc esse videtur, cur visibilis species ex sole procedens, et per pupillam amplificatam intromissa in retinam, ampliorem in illa sedem occupet, majoremque proinde creet solis apparentiam, quam dum per conttactam pupillam eodem intromissa contendit (vid. Epist. I de apparente Magnitudine solis humilis et sublimis, page 6). This solution of Gassendus proceeds on a false principle, viz. , that the pupil's being enlarged augments the species or image on the fund of the eye.

Thirdly, against what is said in sect. 80, it is objected that the me thing which is so small as scarce to be discerned by a man may appear like a mountain to some small insect; from which it follow that the minimum visibile is not equal in respect of all creatures. I answer, if this objection be sounded to the bottom it will be found to mean no more than that the same particle of matter, which is marked to a man by one minimum visibile , exhibits to an insect a great number of minima visibilia .

But this does not prove that one minimum visibile of the insect is not equal to one minimum visibile of the man. The not distinguishing between the mediate and immediate objects of sight is, I suspect, a cause of misapprehension in this matter.

Some other misinterpretations and difficulties have been made, but in the points they refer to 1 have endeavoured to be so very plain that Iknow not how to express myself more clearly. All I shall add is that if they who are pleased to criticise on my essay would but read the whole over with some attention, they might be the better able to comprehend my meaning and consequently to judge of my mistakes.

I am informed that, soon after the first edition of this treatise a man somewhere near London was made to see, who had been born blind, and continued so for about twenty years. Such a one may be supposed a proper judge to decide how far some tenets laid down in several places of the foregoing essay are agreeable to truth, and if any curious person hath the opportunity of making proper interrogatories to him thereon, I should gladly see my notions either amended or confirmed by experience.