J 84 On the Catoptrical and Dioptrical 



13. Cf Father Scheiner, who, in his excellent work on the 

 solars pots, entitled Rosa (Jrsina, describes very clearly many 

 new dioptrical inventions, which others have since at- 

 tempted to appropriate to themselves, was the first who 

 observed that a single object-glass might produce the same 

 effect as a telescope composed of several glasses. "He made, 

 in a camera obscura, experiments similar to those of IVolfi/us 

 and TschirnluM<en, which I have just mentioned ; arid he 

 made them public 70 years before M. Tsckirnhaitsen pub- 

 lished his. Here follow the very words in which he states 

 the results of his experiments, lib. ii. cap. 6. at the end. 



1 >. u Quodsi quis inhis positus, &c. But if any one 

 placed withn (a camera obsevra, or darkened chamber,) 

 apply his eye between the paper i nd the lens, (that is, be- 

 tween the focus, or place of the image, and the lens,) he 

 will see the external objects much larger, erect, and a good 

 deal confused. If he apply his eye to the place of the 

 image, or the paper, he will see a chaos ; and if behind the 

 place of the paper, or the picture, he will see every thing 

 larger and more distinct, but in an inverted posture. Hence 

 appears the vanity of the man's talk (I know not who he 

 was) who applauded himself for the invention of the optical 

 tube; since, the same effect of augmenting visible things, 

 may also be evidently obtained by one large convex lens, 

 from a large sphere." 



15. i( This discovery of father Scheiner was not altoge- 

 ther unknown, or useless, during the interval between 

 his time and that of Tscldrnhausen i for I find, in the de- 

 scription of the cabinet of Manfredi Septala, written in 

 Italian by Scarabelli, and printed at Tortona in 1656, that 

 this learned canon of Milan, celebrated, among other things, 

 tor his famous mirror, which excited flame at the distance 

 of 15 paces *, had also two lenses, one of which was a palm 

 and a half in diameter, and.its focal distance 7 brasses; and 



been equal to his ability, and who, at the place cited in the text, mentions 

 a paper, which he published on the subject in the Acta Eruditorum for 

 October 17 10. He concludes the Scholium quoted above, with these 

 words: •* Nee Credo, &c. Nor do I believe that this differs from the dis- 

 covery of the illustrious TscbirnbauscH, which, as concealed by him, is so 

 h'ghly applauded by the celebrated FontentUe* (Hist-Hcyal Acad, of Sc. 

 An. 1701, .p. 165, Amst. edit.) For, through a glass not pojished with 

 sufficient exactness, I have observed the same things which 'Tschimbausen 

 did .virhhis single lens, and which he described to the iilnstrious Acad. 

 of Sciences; so tint Fonuxtlle had no reason to suspect that there was any 

 secret in the business.'" — Trans/aior. 



* A geometrical pace Dcing 5 feet French, these 15 paces make nearly 

 S« English feet. 



the 



