836 QUATRIÈME COMPLélVIENT X LA DIOPTRIQUE. 1668 — 1692. 



interior. Il doute s'il poiirroic fiicceder, parce qu'on ne l'a pas encore pratiqué '). 

 Sed aliaratio reddipojjet^ uti et de menifco. 



Si hoc modo producere vellet foci diftantiam , etiain tanto perfectior lens effie deberet , iino et 

 superficies irta; utrinque plan» lentis. Ergo niulto facilius unam lentem coiivexam longioris foci 

 dillantix fabricare, ut omittam tôt fupervacuas reflexiones. 



De micromctri inventore agit '). ciijus non advertit me fundamentum jeciffe in 

 Syfteinate faturnio^). la Hire praellare ait lamellam in foco objeftam ad metien- 

 das diftantias *). 



') Molyneux , après avoir cité l'article de Hooke „A tnethod by which a Glass of small Plano- 

 -convex Sphère may be made to refract the Rayes oflight to a Focus of a far greater distance 

 than is usual" (Phii. Trans. du 7 mai 1666, p. 202 — 203) , continue comme il suit: „This, 

 I must confess is an ingenious Hint:But I doubt the desired Effect wiil not be sosuccess- 

 fuUy attained thereby, so as so coiistitute an Object-Glass fora Télescope. For certainly, 

 were it effectuai; 'tis so easie and withal so useful, that before this time it would hâve 

 obtained , and been practised universally. And this makes me question , whether it would be 

 of any better effect, than a Meniscus- Glass, or a Combined Glass oï Prop. XVII. Part. I" 

 (c'est-à-dire la combinaison d'un verre convexe avec un planconcave de plus grande 

 distance focale , placé à quelque distance de l'autre). 



^) Voir les p. 246 — 247 , où l'on lit : „The next Telescopick Instrument which I shall explain , 

 is the Micfometer. Concerning the /mw/Z/ow of the Ingenious Instrument, I hâve only this 

 to say , That for the Honour thereof, there are several Competitors: Mons. Petit , Surveyor 

 of the Fortifications in France, was the first that published to the World the rough Draught 

 hereof, 12 Mar. 1667. Fid. Journal des Scavans, 16. May i66^. After h'im yions. Juzout, 

 another Ingenious Frenchman, publish'd a Tract concerning the exact Mensuration of the 

 Planets Diameters, wherein he seems to challenge the Invention of this Instrument to himself 

 and Mons Picard, Journ. des Scavans, 28 Juin. 1667. and Philosoph. Transact. Num. 21. 

 pfg- 373' lîut 'sst of ail a Candid Englishman of our own , Mr. Rick. Townley , does vindi- 

 cate the first Contrivance hereof to its trueiind original Âut/ior, Mr. Gascoigne^n Englisk 

 Gentleman . who was kilfd in King Charles 1. Service , Fid. Philosoph. Transact. Num. 25. 

 pag. 457. wherin Mr. Towntey (who is of Undoubted Crédit) asserts, that Mr. G<ïsco/^«^ 

 made and used this Instrument before the Civil Wars in England: And that Mr. Townley 

 had then in his Custody two or three of thèse Instruments first devised by Mr. Gascoigne ; to 

 which Mr. Townley himself had added some considérable Improvements. AU which, with the 

 exact Fabrick, and fitting of the Body of the Instrument to a Télescope, we shall find accu- 

 rately discribed in /V/zw. 29. p. 541. Philosoph. Transact. to which I shall therefore refer 

 the Reader. . . .". 



5) Voir la note 1 1 , p. 63 du T. VI. 



'*) Consultez sur ce procédé la p. 843 qui suit. Mais ajoutons que, ni dans le résumé de 

 l'invention du micromètre que nous venons de citer dans la note 2 qui précède, ni ailleurs 

 dans l'ouvrage de Molyneux , le nom de la Hire est mentionné à ce propos. Probablement il 

 s'agit d'une inadvertance de Huygens écrivant „la Hire" au lieu d'„Auzout". 



5) Voir la p. 255 de l'ouvrage de Molyneux, où l'on lit : „The Italian Dictionary, de la Crusca, 

 on the Word Occh'ale , makes this remark, That Frier Jordan de Rivalto, who dyed at Pisa, 

 An. 131 1. in a Book ofSermons which he writ An. 1305. tells his Auditory in one of them , 

 that it is not Twenty years since the Art of making Spectacles was found out, and is indeed 

 one of the best and most necessary Inventions in the World". 



