464 NATURAL SCIENCE. ■ june, 



In the matter of handbooks, however, there is probably no 

 country that has met the wants of the beginner and the skilled 

 amateur so fully as England. Carpenter's " Revelations of the 

 Microscope " has, in each of its seven editions, held its own not 

 only in England and America, but has been largely used on the 

 Continent. Nevertheless, and, perhaps, indeed for this very reason, 

 there is no country in the world where the great Diffraction theory 

 of Abbe, explaining the principles of vision with the modern micro- 

 scope, has been so critically and, at the same time, so warmly and 

 generally received as in England. At the same time, there are few 

 working microscopists whose shelves are without Handbuch der 

 Allgemeinen Mikroskopie by Dr. Leopold Dippel ; and it may be safely 

 predicted that the splendid Theorie der Optischen Instnimente nach Abbe 

 by Dr. Siegfried Czapski, which has just come from the publishers' 

 hands in Breslau, will anywhere find a more appreciative circle of 

 students than in England ; but the English microscopist, who is 

 not only a student of what the microscope does and can reveal, but 

 also a critic and connoisseur of the principles and modes of manufac- 

 ture of the instrument, really needs books of the class above indicated. 

 The day for handbooks that are better illustrations of the art of the 

 printer and the wood engraver than of the science and art of 

 microscopy has passed away. 



In the treatise now before us great pains has been taken to pre- 

 sent in its most attractive form the facts of microscopical science as 

 known to us ten or fifteen years ago, and to make an appendage to 

 these of the most recent knowledge which has come to us as the 

 result of theory and practice in more recent times ; but between the 

 old and the new there is no coherence. The treatise purports to 

 cover all the area of modern microscopy, in the interests and for the 

 benefit of the amateur. That it fails of its purpose there can be no 

 doubt. It does this partly because of its method. It adopts the 

 older style of teaching, and simply forces the new optical doctrines 

 and details of the new methods of manufacture and manipulation 

 (where given at allj into a place or position in the text without pre- 

 face or explanation. The result is that we obtain an account of the 

 " Theory of Microscopic Vision " which is in itself excellent, but 

 quite beyond the range of the class of reader for whom the book is 

 ostensibly written, because, clear as Abbe is in the exposition of his 

 great theory, it needs at least a chapter of explanation and introduc- 

 tion to make it fully accessible to the ordinary, and especially the 

 non-mathematical, reader. The result is, that this book appears to us 

 to fail from the fact that it directs the student to go beyond his depth, 

 without even the semblance of assistance on the one hand, and, on 

 the other, guides him with great care over shallows where no guide 

 was needed, save the catalogues of certain English and foreign 

 opticians — that is, as to the forms of certain instruments mostly on 

 the same type. 



It is quite true that the tyro wants above all things to know how 

 wisely to purchase an instrument ; but this is not unfolded to him 

 by an indiscriminating description of the microscopes of certain 

 makers however diverse, but by an unbiased description of the 

 essentials of any good instrument, and such an account of practical 

 tests as would enable a beginner at least to see how far a certain 

 pattern of stand, or a specific instance of workmanship, answers to 

 this set of requirements. And in furnishing these data there need be 

 no more dogmatism than in an experienced photographer's affirmation 



