REVIEWS. 85 



Achromatic Microscopes." The second part, which our author entitles 

 " The Use of the Microscope," supposes that the reader is possessed of the 

 information contained in Part I., and also of some of the instruments 

 described in it, but requires some directions as to how to use the instru- 

 ment, with whose parts only he is familiar. The eye and the hand require 

 alike to be educated, before even the most ordinary observation can be 

 made with accuracy. Here Mr. Quekett's great experience and practical 

 knowledge of the instrument he writes upon is evident in every page, 

 while he describes, with brevity and accuracy, how to observe, how to 

 illuminate objects, and such kindred subjects. The last part (" Manipula- 

 tion") is devoted to what we conceive the most difficult and important 

 portion of the work we mean, those niceties of manipulation which, when 

 once mastered, appear so simple, but which are almost impossible to de- 

 scribe to those who have not had opportunities of seeing them performed. 

 These are subdivided into their appropriate heads, and under each full 

 directions are given, which will, with a little patience and care, enable the 

 beginner to perform most of the niceties of microscopical research with 

 satisfaction to himself. We cannot close this treatise without expressing our 

 conviction that, as a single work on the subject it treats of, it is inferior to 

 none ; and in making this statement we are not insensible to the advantages 

 which many others present, and more especially those devoted to parti- 

 cular branches of research, which should, however, be regarded as consti- 

 tuting a particular class, and judged as such. 



Leaving Mr. Quekett, our attention has been caught by the face of an 

 old friend, and a name which is well known to observers ; and though the 

 date of the work may appear, perhaps, rather antiquated, still we cannot 

 pass it by in silence, as it treats of a class of microscopes now but little 

 known. It is the " Micrographia" of Dr. Goring and Mr. Pritchard, and 

 is principally occupied by a consideration of Reflecting, Solar, and 

 Oxy-hydrogen Microscopes. Though some seventeen years of active and 

 busy progress have elapsed since its appearance, in which great changes 

 have been effected in the science of observation, still we cannot forget that 

 a new and most important era in microscopic science commenced with the 

 improvement of the reflecting microscope (constructed by Amici, in 1815) 

 by Sir David Brewster, Dr. Goring, and Mr. Pritchard. Since then the 

 progress in this country has been rapid, and more particularly so within 

 the last few years. As early as 1738, reflecting microscopes were in use ; 

 but, from defective construction, they were gradually abandoned, until 

 Professor Amici, of Modena, whose attention had been directed, in 1812, 

 to the improvement of the achromatic object-glass, during his investigations, 



