576 SUMMARY OF CURRENT EESEAEGHES RELATING TO 



application of it to examine some very minute animals ; and if he him- 

 self neither then nor for many years after made any mention of it 

 publicly, this cannot take away from him or diminish the merit of the 

 invention. 



It is not to he believed however, that Galileo after these first experi- 

 ments quite forgot the Microscope, for in preparing the Saggiatore 

 between the end of 1619 (5) and the middle of October 1622 (6) he 

 spoke thus to Lotario Sarsi Segensano (anagram of Oratio Grassi Salo- 

 nense) (7) : — 



" I might tell Sarsi something new if anything new could be told 

 him. Let him take any substance whatever, be it stone, or wood, or 

 metal, and holding it in the sun, examine it attentively, and he will see 

 all the colours distributed in the most minute particles, and if he will 

 make use of a telescope arranged so that one can see very near objects, 

 he will see far more distinctly what I say." 



It will not therefore be surprising if in 1621 (according to some 

 letters from Rome, written by Girolamo Aleandro to the famous M. de 

 Peiresc (8) ) two Microscopes of Kuffler, or rather Drebbel, having been 

 sent to the Cardinal of S. Susanna, (9) who at first did not how to use 

 them, they were shown to Galileo, who was then in Rome, and he as 

 soon as he saw them explained their use, as Aleandro writes to Peiresc 

 on the 24th May, adding, " Galileo told me that he had invented an 

 Occhiale which magnifies things as much as fifty thousand times, so 

 that one sees a fly as large as a hen." 



This assertion of Galileo that he had invented a telescope which 

 magnified 50,000 times, so that a fly appears as big as a hen, must 

 without doubt be referred to the year 1610, and from the measure given 

 of the amplification by the solidity or volume the linear amplification 

 (as it is usually expressed now) would have been equal to something 

 less than the cubic root of 50,000, that is, about 36, and that is pretty 

 fairly the relative size of a fly and a hen. 



Aleandro's letter of May 24th (1624) does not state at what time 

 Galileo saw the telescope and explained the use of it, but another letter 

 of Faber's to Cesi, amongst the autograph letters in the possession of 

 D. B. Boncompagni, (10) says (11th May) : — 



" I was yesterday evening at the house of our Signer Galileo, who 

 lives near the Madalena ; he gave the Cardinal di Zoller a magnificent 

 eyeglass (11) for the Duke of Bavaria. I saw a fly which Signer Galileo 

 himself showed me; I was astounded, and told Signer Galileo that 

 he was another creator, in that he shows things that until now we did 

 not know had been created." 



So that even on the 10th May, 1624, Galileo had not only seen the 

 telescope of Drebbel and explained the use of it, but had made one 

 himself and sent it to the Duke of Bavaria. 



We lack documents to show how this Microscope of Galileo was 

 made, that is, whether it had two convergent lenses like those of 

 Drebbel. A letter of Peiresc of the 3rd March, 1624, says that " the 

 efi^ect of the glass is to show the object upside down . . . and so 

 that the real natural motion of the animalcule, which, for example, goes 

 from east to west, seems to go contrariwise, that is, from west to east ") , 

 or whether it was not rather composed of a convex and a concave lens, 

 like that made earlier by him, and used in 1610, and then almost for- 

 gotten for fourteen years. 



