ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 725 



thus anticipating the first micrometers of Gascoigne, Montanari, aud 

 Huyghens. 



Now this same Eustachio Diviui, in a letter which has heen printed, 

 addressed to Count Carlo Antonio Marozini on the 15th of July, 1663, 

 wrote thus :— ' Now that we are upon the subject of telescopes fitted 

 with the single lens, I ought to tell you of a remarkable matter ; I 

 hare seen strange things. While looking at some object, such as a 

 bas-relief or those arms carved in stone which are commonly put upon 

 walls, their plane parts appeared depressed and level with the wall, 

 while all the rest of the arms were devoid of relief. 



But the curious thing is, that the relievos which I have mentioned 

 are seen as if hollowed out, whereas they are really raised up. When 

 I discovered this, I showed it to other persons of enquiring disposition, 

 and by looking several times at the same place, finally convinced 

 myself that I had been deceived by the light which it received from 

 the sun, for in the morning it appeared hollow, in the evening in 

 relief, and in other parts in relief in the morning and hollow in the 

 evening. The Microscopes with two glasses, which also show the 

 objects to me reversed, usually do the same with a difference in the 

 glasses, which I do not as yet understand. They magnify a thousand 

 times, and by the conditions of this power cannot be applied to 

 objects which are rather large ; therefore I have sometimes added 

 another lens with a curvature considerably greater than that of the 

 small lens, taking away the latter and inserting the former, which 

 does not magnify so much, but serves for rather large objects, and 

 with them produces a most beautiful effect with the greatest clearness. 

 With this apparatus I have looked at an old coin in order to see 

 letters which could not be read. Sometimes I have seen the places 

 in relief reversed and, changing their position (so to speak), stand on 

 the right-hand side of the Microscope, and if I place myself on tho 

 left I see in relief that which when on the right I considered to be 

 hollow. But what seemed to me altogether strange, and has happened 

 to me more than once is, that when looking at another object in relief, 

 I see it hollow, and on changing my position I still see even the part 

 in relief hollow. However, I leave all this to distinguished intellects 

 to speculate upon, and return to our telescope.' 



The 15th of July (Gregorian notation), 1663, is earlier by 5 years 

 7 mouths and 15 days than the 18th of February (Julian notation), 

 1669 ; by this period, tlierefore, does Divini have precedence of the 

 English academicians in the discovery of the pseudoscopy of reliefs, 

 and by a still greater time is he beforehand in tho endeavour to 

 explain the phenomenon, for he attributes it to ' deception of the 

 light,' and as his microscopical observations left him somewhat 

 perplexed as to such a reason, ho referred the matter to distinguished 

 int<dlects, which, however, have not known how to find a better one, 

 and repeat (only in a better form and somewhat aided by experi- 

 ments) the same explanation which Divini had proposed two centuries 

 ago," * 



• A BiUioKrajihy of eleven of the books and papers referred to is app nded. 

 Sor. 2.— \oi.. V. 3 B 



