VI PREFACE. 



were burnt except one set as far as p. 374, which the publishers 

 had retained in their possession, together with a few of the 

 woodcuts. 



Under these circumstances the publishers had to consider the 

 alternatives (1) of abandoning the issue of the volume ; or (2) of 

 incurring the additional expense of re-translating the portion of 

 the work totally lost by the fire, replacing the missing woodcuts, 

 and reprinting the whole ; or (3) of reprinting as far as p. 374 only, 

 omitting therefore Part VIII. (Microphysics), Part IX. (Micro- 

 chemistry), and Part X. (Morphology). It was finally decided to 

 adopt the last course, hence the present issue. 



Whilst it is much to be regretted that this translation should 

 only now be issued, microscopists will no doubt appreciate the 

 advantage of having a version in English of a work which has 

 received high commendation from both English and foreign critics ; 

 and it is hoped this volume may be supplemented before long 

 by an English version of the further researches in Microscopical 

 Optics by Prof. E. Abbe, of Jena, which have extended so much our 

 knowledge of the matters dealt with in Naegeli and Schwendener's 

 work. 



