SEEING BY AID OF THE LENS. 



201 



watch its development into the little 

 plant and its gradual growth into the 



giant tree. 



or we 



may start with the 

 swelling bud in springtime, watch it 

 throw aside its winter coat, and soon 

 become the mature leafy branch or the 

 beautiful flower. In either case we have 

 seen the growth of a tree or a branch. 



we have seen the transformation of the 

 inert matter of the soil, with the sun- 

 light energy, into a living organism, and 

 we are studying nature. The man who 

 has studied the life of a tree has a new 

 friend on earth and lias a new insight 

 into the heart of things. 



YAID 

 THE LENS 



THE 1V0>DERF[ T L AND BEAUTIFl'L 

 DIATOMS. 



That all waters which be upon the 

 earth teem with animal and vegetable 

 life even more abundantly than the earth 

 bears its burden of living creatures, has 

 been so often said that the remark has 

 become hackneyed to a tenuity that is 

 nearly unable to support its own weight. 

 Vet the assertion is strictly true, and no 

 one is more familiar with the fact than 

 the microscopist. The seas of the world 

 are crowded with beings from "levia- 

 than" down to creatures so minute, that 

 the highest powers of the microscope are 

 required to make them only imperfectly 

 visible. The fresh waters are no excep- 

 tion. Every drop that comes from the 

 public reservoir into the writer's house, 

 brings, with it an average of five living 

 animals, all minute to the point of invis- 

 ibility, and all harmless, yet they are 

 present. Vegetable life is no less abund- 

 ant. Setting aside all thought of "mi- 

 crobes," bacilli and bacteria, other mi- 

 nute plants thrive, flourish, act their 

 part, and die within the waters in even 

 greater numbers than on the land, and 

 these numbers are often so enormous 

 that the mass becomes visible to the 

 naked eye. 



A diatom is a plant enclosed in a case 

 of silica, upon whose surface nature has 

 lavished some of her most exquisite spec- 



imens of minute carving, elevated lines, 

 delicate dots, whose character is even 

 now not clearly understood, apertures, 

 circular and hexagonal, and so small that 

 the optical difficulties involved in their 

 demonstrations are almost insuperable, 

 and have occasioned man}- a word}' war 

 among microscopists. These siliceous 

 cases being indestructible even by boil- 

 ing mineral acids, have long served as 

 tests for the optical qualities of the best 

 microscope objectives, and also for the 

 good nature and self-control of contend- 

 ing microscopists. 



A glance at any of the accompanying 

 illustrations will give an incomplete and 

 inadequate notion of a small varietv of 

 the forms, and perhaps of some of the 

 surface markings, although to show 

 these clearly demands high magnifying 

 power, and careful illumination of the 

 microscope. To exhibit variety of form 

 the arranged groups, Figs, i, 2, 3, are 

 particularly pleasing, as they are pre- 

 pared in an artistic way, and are well 

 worth extended examination. A few of 

 the objects in Fig. 2. especially those 

 in the outer circle, are not diatoms, but 

 have been introduced to give the picture 

 the desirable finish and artistic effect. 

 When the reader remembers that all 

 these objects are invisible, except under 

 the microscope, he may appreciate the 

 skill of the man that could and would 



