ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 157 



mastery of the difficulties and peculiarities of our instrnment is the 

 absolutely essential precursor to successful work of any original kind, in 

 any direction we may choose. 



I note with great pleasure that several of the provincial societies are 

 making manipulation special, and employing demonstrations in histological 

 methods, microscopical dissections, mounting of various kinds, &c. It 

 would be a great gain, in my judgment, in all such societies, to have similar 

 and progressive demonstra.tions on the practical use of all lenses and all 

 apparatus employed to secure their highest efficiency, in various kinds of 

 investigation. No doubt it may be said that small societies are not always 

 possessed of such members as could give this desirable information. This 

 is true : but the society exists to secure this end ; and since application, 

 with such lenses and apparatus as may be within reach of the members, is 

 all that is required in addition to ordinary intelligence, each member may 

 advance, and the most efficient help and stimulate the rest." 



Cherubin d'Orleans' *La Vision parfaite.'— Pere Cherubin d'Orleans 

 was the first known inventor of the Binocular Compound Microscope, 

 which he described and figured in his work, ' La Vision parfaite,' pub- 

 lished in Paris in 1677, * the Latin edition, ' De visione perfecta,' translated 

 by himself, being issued at the same time. Numerous references to this 

 work have appeared from time to time in the literature of the Microscope ; 

 but hitherto the second volume, which was published in Paris in 1681, 

 was entirely unknown, the first volume giving no indication, either on the 

 title-page or otherwise, of the existence of a second. In a recent visit to 

 Antwerp we were surprised to discover a copy of the work with the two 

 volumes bound together. This second volume f is of special interest in 

 microscopy, from the fact that it contains a full description, with figures, 

 of Cherubin's ' Microscope Universel,' in which is described the first ap- 

 plication (so far as we are aware) of a rotating disc of object-lenses. There 

 are eight difierent powers, applied at the nose-piece of the body-tube, a 

 system practically identical with that adopted in England sixty or seventy 

 years later by B. Martin. This was probably suggested to Cherubin 

 by his rotating object-disc, which he figured (plate 31, fig. 7) and described 

 (p. 262) in his ' Dioptrique Oculaire,' published in Paris in 1671. 



Value of the Microscope in Trade.J — " D." points out of what infinite 

 value the Microscope is in trade ; and of trades selects that of brewing, 

 " because it will be apparent to all readers that a brewer without a Micro- 

 scope is almost analogous to a peacock without a tail." 



Since the remarkable revelations of M. Pasteur, the brewing trade has 

 been completely revolutionized, and a man nowadays who does not know 

 how to use the Microscope, and who, in fact, is not an able manipulator of 

 that instrument, does not come within the definition of master brewer. 

 " Science has so beautified the labours of the brewers, that they have 

 been elevated above the level of empiric soup-makers to that of, at least, 

 semi-professional men ; " and he doubts not but that " time's effacing 

 fingers will ere long entirely sweep away the old ignorant class of men who 

 perhaps knew well how to wash a barrel, but had no idea of the influence 

 of certain salts and organisms on the character of their malt extract." 



After pointing out the value of the Microscope in determining, 



* Cherubin d'Orleans, 'La Vision parfaite: ou le concours des deux asea de la 

 vision en un seul point de I'objet,' xxvi. and 187 pp., frontispiece, and 16 pis. and 

 4 figs., fol., Paris, 1677. See this Journal, 1882, p. 253. 



t ' La Vision parfaite : ou la veue distincte par le concours des deux axes en un seul 

 point de I'objet,' tome ii., xxviii. and 239 pp., 12 pis., fob, Paris, 1681. 



I Engl. MeJi., xliv. (1886) p. 391 (3 figs.). 



