202 



THE GUIDE TO NATURE. 



IT' Z\A 



Fig. i. 



pick up, one by one, the minute things, 

 carry them on the tip of a hair from be- 

 neath one microscope to a disc of glass 

 under another instrument, and there ar- 

 range them in the charming groups here 

 photographed. The time, the patience, 

 the skill required in such work are be- 

 yond words to describe. 



Fig. 2. 



( )n this page are shown diatoms ar- 

 ranged in artistic groups by the skill 

 and the indomitable patience of a pro- 

 fessional preparatenr of microscopical 



slides. 



Fig. 3. 



The other illustrations (Figs 4 to 9), 

 have been selected to show not only va- 

 riety of shape, but peculiarity and dif- 

 ferences of sculpturing. Fig. 4 is not- 

 able in both these features; Fig. 8 might 

 be the housewife be compared to the lids 

 of certain kitchen utensils, with depres- 

 sions for the thumb and finger; Fig 9, 

 Heliopelta, is the '■sun-shield," the two 

 sets of rays being beautifully shown. 



The scientific name of each diatom is 

 designed to describe some quality pecu- 

 liar to the species or to the genus, al- 

 though it is sometimes difficult to decide 

 just what its sponsor meant by his combi- 

 nation. Fig. 4. Coscinodiscus\ is the 

 "sieve-like disc" ; Fig. 5. Triceratium sex- 

 angidatum, is the diatom with three lit- 

 tle horns, as some of the species have, 

 and six angles; Fig. 8, is another species 

 of Triceratium, and apparently with 

 greater reason for the name. 



Many years ago. Professor J. W. 

 Bailey, writing on this subject, said that 

 the mountain brooks about West Point, 

 had the surface of the mud "literally 

 covered in the first warm days of spring 

 with a ferruginous-colored mucous mat- 

 ter, about a quarter of an inch thick, 

 which, on examination by the microscope, 

 proves to be filled with millions and mil- 

 lions of these exquisitely beautiful sili- 

 ceous bodies. Every submerged stone, 

 twig, and spear of grass is enveloped by 



