ZOOLOGY AND BOTANY. MICROSCOPY. ETC. 587 



the Dutch telescope), and therefore diflfered, as before stated, from 

 Drebbel's Microscope. 



On the other hand, no testimony in favour of Galileo's invention can 

 be more explicit and more sure than Wodderborn's, corroborated by- 

 Galileo's own declaration in 1624, after he had seen Drebbel's Micro- 

 scojies, as referred to by Aleandro. 



As to the pretensions put forward by Pierre Borel in favour of 

 Jaussen, (41) or to the boasts of Francesco Fontana, (42) it will suffice 

 to show how the first were only put forward in 1655, that is, half a 

 century after the supposed invention, and the others in 1646, after 

 Fontana had had notice of Drebbel's Microscopes in 1625, indeed had 

 seen some in Fabio Colonna's house without at first understanding the 

 meaning of them, as is shown by certain letters of Colonna, which were 

 printed in the last century in the ' Giornale dei Letterati ' of Eome. (43) 



D. Chorez, Drebbel, and Fontana, who after 1610 made Microscopes 

 ^\-ith a convex and a concave lens, were not inventors, but reproducers of 

 Galileo's compound Microscope. Others coming later, without usurping 

 the invention of Galileo, spoke of it without giving it as his. So did 

 Mauziui in his ' Occhiale all' occhio ' (1660), and 1 am convinced that 

 in looking through the writers on optics after Manzini we should find 

 several who since that time described Galileo's Microscope without 

 attributing it to its real author. (44) 



Also the ingenious French optician Charles Chevalier, in his 

 ' Manuel du Micrographe,' published in 1839, brought forward again 

 as a novelty the Galilean Microscope, being ignorant without doubt that 

 the invention was over 200 years old. 



Latterly the same thing happened to the celebrated German physio- 

 logist Ernest William Briicke, whose " working lens," which now all 

 naturalists know under the name of the " Briicke lens," is really 

 nothing but the ancient "occhialino" of Galileo, modernized in shape, 

 with better lenses, and limited to lesser amplification. 



At the meeting of the 8th May, 1851, Prof. Briicke (45) presented 

 to the Academy of Sciences of Vienna a species of Microscope, termed 

 by him -working lens (Arbeitsloupe), intended to facilitate anatomical 

 studies, because it has a large frontal distance, in spite of its amplifying 

 power of six and more diameters. This working lens consisted of a 

 brass cylinder 90 mm. long and 40 mm. in diameter, which bad at one 

 extremity a couple of achromatic lenses taken from an ajilanatic ocular of 

 a large compound Microscope of Plossl, and at the other extremity a 

 biconcave lens taken from an opera-glass. The two converging glasses 

 placed together acted as a single lens, but rendering the field of vision 

 more uniform and clear. The objects to be observed were placed at 

 75 mm. from the objective, and appeared to be enlarged 5 times at 

 165 mm. distance from the eye, and about 6*6 times at 8 Parisian 

 inches, or 21 6 "56 mm. from the eye. 



If the same enlargement at the same distance was wanted with a 

 single lens, a lens of 41 • 25 mm. principal focal distance would have to 

 be used, holding it at 33 nmi. instead of 75 mm. from the object. And 

 if placing the object at 75 mm. from a lens we had tried to enlarge it 

 5 times, we must have had recourse to a lens with a focus of 93* 74 mm., 

 and a virtual image five times as large as the object wcnild have been 

 formed not at 165 mm., nor at 217 mm., but at 375 mm. from the eye. 

 In either case the observer would have been inconvenienced either by 



