PREFACE. 
Tue following pages, part of the Micro- 
scopic Cabinet, are presented to the pub- 
lic, in the hope that they may prove 
interesting to those who do not desire to 
peruse the part on Practical Optics con- 
tained in that work. 
The reader will probably consider the 
Author as justified in this undertaking 
when informed that these Essays have 
been lately translated and published in 
France, at the expence of an eminent 
Artist residing there. A selection from 
that work has also been translated and 
published in Germany. 
At the time of the publication of the 
Microscopic Cabinet, little attention was 
paid by scientific men to microscopic 
pursuits :—indeed, it was then not un- 
