DIATOMS in 



parisons are impracticable where the supply is 

 unbounded. Yet there are some objects in Nature 

 which arrest our attention more than others, and 

 pictures of which stand out more prominently in our 

 minds. Even the number of these appears to be 

 infinite, and we frequently speak in anomalous terms, 

 and say of each member of a host of wonderful things, 

 " This is the most wonderful and the most beautiful 

 object in the world." 



' It is doubtful whether there exists in the animal, 

 vegetable, or mineral kingdom, any object which em- 

 braces in such small dimensions so much of the truly 

 marvellous and beautiful as the tiny plants called 

 diatoms. So great is the fascination which attends 

 the examination of diatoms, that men have been in- 

 fluenced to put aside all other microscopic studies so 

 that they might give them their unstinted and un- 

 divided attention.' 



The lady's attention being fixed, I proceeded : 

 ' A watchmaker cf large practical experience held 

 up between his eye and the gas flame one of my 

 diatom slides, and well knowing that from the nature 

 of his occupation he could focus his eyesight to a 

 very small point, I fully expected he would discover 

 the specimen. But he gave up the task, declaring it 

 his belief that there was absolutely nothing on the 

 glass slip. If these particular diatoms defy the eye- 

 sight powers of this skilled artificer, I am surely justi- 

 fied in pronouncing them invisible, or below the 

 range of ordinary vision. 



