596 SUMMARY OF CURRENT RESEARCHES RELATING TO 



propinquissime et e converso. Nam possumus sic figurare perspicua, et taliter ea 

 ordinare respectu nostri visus et rerum, quod frangentur radii et flectentur quorutn- 

 cumque volyerimus ut sub quocumque angulo volverimus videbimus rem prope vel 

 loDge, et sic ex incredibili distantia legerimus literas minutissimas et pulveres ac 

 arenas numeraverimus propter magnitudiaem anguli sub quo videremus, et maxima 

 corpora de prope vix videremus propter parvitatem anguli sub quo videremus; nam 

 distantia non facit ad hujusmodi visiones nisi per accidens, sed quantitas anguli. Et 

 feic posset puer apparere gigas, et unus homo videri mons, et in quacunque quan- 

 titate, secundum quod possemus hominem videre sub angulo tanto sicut montem, et 

 prope ut volumus et sic parvus exercitus videretur maximus, et longe positus appa- 

 reret prope, et e contra ; sic etiam faceremus soletn et lunam et stellas descendere 

 secundum apparentiam hie inferius, et similiter super capita inimicorum apparere, et 

 multa consimilia, ut animus moitalis ignorans veritatem non posset sustinere." 



(27) ' Monografia della Vetraria Veneziana e Muranese,' Venezia, 1874, 1 vol. 

 8vo. Ibid., parte antica, " SuUe origini e suUo svolgimento della vetraria Veneziana 

 e Muranese," by Baitolomeo Cecchetti, pp. 12 and 13. 



(28) T). Nicolai de Cusa Cardinalis etc. Opera. Basilese, 1565, 1 vol. fol. Ibid., 

 p. 267. 



" Liber qui inscribitur de Beryllo incipit. Cap. ii. Beryllus, lapis est lucidiis, 

 albus et transparens cui datur forma, coucava pariter et concava, et per ipsum videns, 

 attingit prius invisibile." 



(29) Littre, at the word Lunette, in the historical part of his dictionary, quotes 

 a note of the sixteenth century reported by De la Borde in his work, ' Sur les Emaux ' 

 (p. 164), and that is the note reported in the text. 



(30) ' Hieronimi Sirturi Mediolanensis Telescopium, sive Ars perficiendi novum 

 illud Galilsei visorium instrumentum ad sydera, in ties partes divisa; quarum 

 prima exactissimam perspicillorum artem tradit, secunda Telescopii Galilsei abso- 

 lutam constructionem, et artem aperte docet. Tertia alterius Telescopii faciliorem 

 usum ; et admirandi sui adinventi arcanum patefacit. Ad serenissimum Cosimum II. 

 magnum Etrurise Ducem. Francofurti, Typis Pauli Jacobi, impensis Lucse Jennis, 

 1618,' 4to (82 pp. and 2 pis.). The measures of the lenses indicated in the text are 

 given by the figure on the large table intercalated after p. 18 in Sirturo's pamphlet, 

 and seem derived from the Braccio da panno (yard measure for cloth) of Venice of 

 683 mm. 



(31) ' Jo. Bapt. Portse Neapolitani Magise Naturalis libri xx. ab ipso Authore 

 exi^urgali, et superaucti, in quibus scientiarum naturalium divitise et delitise 

 demonstrantur. . . . Neapoli, apud Horatium Salvianum, d.d.lxxxvhii.'(]589), 4to. 



lb., lib. xvii. cap. x., xi., xii., xiii., and cap. xxi. pp. 269-71, and pp. 278-9. 



No reference of Porta relating to lenses is to be found in the first edition of the 

 Magia, which is of the year 1558. 



'Magiae Naturalis sive de Miraculis rerum naturalium libri iiii. lo. Baptista 

 Porta Neapolitano Autore. Neapoli, apud Mattliiam Cancer, m.d.lviii. cum gratia et 

 privilegio per decennium.' 1 vol. fol. 



The things written by Porta about lenses in his work, 'Joan. Baptise Portse 

 Neap. De refractione optices parte. Libri novem. Ex officina Horatii Salviani. 

 Neapoli apud lo. Jacobum Carlinum et Antonium Pacem,' 1 vol. 4to, have no 

 scientific value whatever. 



lb., lib. viii. pp. 173-88. 



(32) Codice Boncompagni: 'Lettere di Molti Accademici Lyncei eco.,' cart. 354 

 recto. Letter of Nicolo Antonio Stelliola Lynceo to Prince Cesi, written from Naples 

 on the 10th of April, 1615 :— 



" I will not now withhold what happened to me as to my Academic Brother 

 Giov. Battista della Porta of holy memory : it is that on visiting him two days before 

 he took to his bed in this his last illness, he said to me that the enterprise of the 

 Telescope had killed him ; being, as he said, the most difficult and arduous one 

 which ever he Lad undertaken." 



Let it be noticed that before the death of Porta, which happened on the 4th 

 February, 1615, Kepler's two works had been published: ' Ad Vitellionem Parali- 

 pomena' in 1604, and 'Dioptrice' in 1611, in which the doctrine of lenses and 

 telescopes was almost completely worked out. 



(33) ' Considerazioni d' Alimberto Mauri sopra alcuni luoghi del Discorso di 

 Lodovico delle Colombe intorno alia stella apparita 1' ottobre dell' anno 1604. In 

 Firenze appresso Gio. Antonio Caneo, 1606,' 4to. 



(34) ' Galileo Galilei ed il Dialogo de Acco di Ronchiti da Bruzene, ecc. Studi 



