PREFACE 



ALTHOUGH no changes of so important a character as those which 

 distinguished the Vllth Edition of this book from the editions 

 that had preceded it have been necessitated, yet a thorough and 

 complete revision of the entire text has been made, and everything 

 of importance to Microscopy which has transpired in the interval 

 has been noted. This applies to the theory of the microscope as 

 well as to its use. 



We have adopted a classification of microscopes that we hope 

 ..may be of value to many in the purchase of a stand, especially as we 

 also point out with pleasure the great and successful efforts which 

 English, Continental, and American makers have made within the 

 last few years to supply good and useful microscopes at a greatly 

 reduced price. 



Invaluable aid and suggestion have been given me by my friend 

 MR. E. M. NELSON, ex-President of THE ROYAL MICROSCOPICAL 

 SOCIETY, to whom my thanks are due. MR. ARTHUR BOLLES 

 LEE has rendered unique service in the section dealing with the 

 Preparation and Mounting of Objects ; and to PROF. E. CROOKSHANK 

 I am indebted for valuable and useful help. In the matter of the 

 Application of the Microscope to Geological Investigation the 

 REV. PROF. T. BONNEY, F.R.S., has been, fortunately, my valued co- 

 adjutor. On the subjects of Micro-crystallisation, Polarisation, and 

 Molecular Coalescence, I have received the expert advice and help 

 of MR. W. J. POPE, F.I.C., F.C.S., &c., Chemist to the Goldsmiths' 

 Technical Institute, whose large practical knowledge of this depart- 

 ment of chemistry is widely known. 



For the valued help of PROF. A. W. BENNETT, M.A., B.Sc., 

 Lecturer on Botany at St. Thomas's Hospital, -and of PROF. F. 

 JEFFREY BELL, M.A., Professor of Comparative Anatomy and 

 Zoology, King's College, London, I have, as in the former Edition, 

 to make my appreciative acknowledgments. 



It is hoped that this Edition may, as its predecessors have done, 

 prove of practical help to many in understanding the scientific 

 of the microscope. 



W. H. DALLINGER. 

 LONDON : MARCH 1901. 



EKUATUM. Page 333, eleventh Hue from the bottom, read 'Plate IV.' not III. 



