CLASSIFICATION. 53 



I have felt when having to lose sight of a very 

 interesting specimen, perhaps new to me at the 

 time. After watching it for hours, a period must 

 come when the drop containing it will either eva- 

 porate, or an additional drop or two must be 

 mixed with it, and then the probability is that it 

 may never be seen again. If very small, and not 

 fixed to a leaf, this is most likely to happen. The 

 movements of many are also so rapid, and the 

 impossibility of touching them so great, that it 

 is only wonderful we have such correct and 

 minute accounts of these atoms, which are so 

 completely invisible to the naked eye. 



As these pages only aspire at being considered 

 an introduction to an interesting study, I shall 

 not enter on a scientific arrangement, further than 



F3 



