ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 593 



Here there comes, in the series of letters from Peiresc to Alcaudro, a letter from 

 Aix of January 12th, IG'24, in which Peiresc mentions again the courier of Avignon, 

 who took the box with the occhiali, as he speaks of it again in another letter of 

 February ISth, but neither one nor the other containing new particulars concerning 

 this subject, we have thought it useless to publish them. Between these two 

 letters must be placed the following from Girolamo Aleandro to Pcinsc : — 



"Eome, February 2nd, 1G24. — . . . "With the same letter of the 2nd I received 

 the box with the occhiali, which I took at once to the Cardinal of Santa Susanna, 

 and I left in his hand your Lordship's old letter in which you wrote in wliat way they 

 were to be used. It was easy to set up the little one, but we have not yet found the 

 way of using the large one, although we had the helj) of mathematicians, and we have 

 feared that in some part it is out of order. But the Cardinal of Santa Susanna will 

 have written to you more diffusely on all this. . . ." 



From Peiresc to Aleandro: — 



" Aix, March 3rd, 1624. — I am very much surprised that you have not managed 

 the large occhiale ; if the glasses are not broken it is easy to find their proportion. 

 I will await the more ample relation which you tell me will be sent me by the Illus- 

 trious Cardinal of Santa Susanna, in order to answer the dilSculties and give some 

 means of obviating them, so that the instriiment may succeed. The greatest difficulty 

 to the most perfect success lies in the movable plate upon which the oVjject is placed, 

 so as to keep it motionless under the point at which tlie line which passes from the 

 eye tlirougli the centre of the two glasses terminates. For, when once one has learnt 

 the use of it, it is operated most easily and with great pleasure and delight ; one sees 

 a tiny live animal walking and one retains it precisely under the line by moving the 

 little plate contrariwise to the place towards which the insect is directing itself. 

 Because the effect of the occhiale is to show the object upside down, and to cause 

 the real motion of the little animal to seem contrary ; as fur example, if it be going 

 from east to west it will appear to go from west to east. As to the distance of the 

 glasses from each other, there are two Umits out of which they do not make any 

 considerable effect of increase and greater or lesser distinctness. And as to the dis- 

 tance between the object and the first glass, it must likewise be greater or less, 

 according to that of the glasses from one another; that is, if the distance of the 

 glasses between each other is the gi-eater, the distance of the object must be less, 

 and as you decrease the distance between the glasses, so must you increase the 

 distance of the object." 



From Aleandro to Peiresc : — 



''Eome, 29th March, 1624. — The large occhiale is unbroken, but we cannot 

 find a way of adjusting it rightly, because although we have directed the opening as 

 we ought to have done towards the object placed upon the little plate, and we have 

 also discovered the magnification, yet we did not see it distinctly, though your Lord- 

 ship aflirmed that it showed things more distinctly than the little one. We shall go 

 on trying it until we find the way. But it is a long time since I have seen the 

 Cardinal of S. Susanna. . . ." 



From Peiresc to Aleandro: — 



"Aix, 15th April, 1624. — Postscript. — Having remembered that Signor Melano, 

 bearer of the present, has formerly seen in my hand the occhiale of the Illustrious 

 Cardinal of S. Susanna, I have gone over with him the way to work it, and if your 

 Lordship will let him see the occhiale again he will try it, and can direct your Lordship 

 and any one it may please you to show it to after the said Illustrious Sigr." 



From Peiresc to Aleandro : — 



" Aix, 10th and 17th May, 1624. — It is true that I wrote to you of the large 

 occhiale that one saw the object clearer than in the little one, but to have the full 

 effect of it, the object must be lighted up by the sun, otherwise it remains too dark. 

 But in the sun you will see a stupendous effect, when you have found the way to 

 use the instrument." 



From Aleandro to Peiresc : — 



"Eome, 24th May, 1624. — . . . Signor Melano, engraver on copper, came 

 afterwards to see me with your Lordship's letter of the 15th, and I offered to serve 

 him and recommend him to Villamena, Tempesta, and to whomever he liked. He 

 told me he would return to see me, but I have not seen him since. I will also take 

 him to the Cardinal of Santa Susanna. Galileo has been here these last few days, 

 and at once found how the occhiale was to be used, but we don't think we see things 

 very clearly and we will try with Melano. 



Galileo told me that he had discovered an occhiale which magnified these small 



