•20 THE AMERICAN BOTANIST 



where the plants are and the adaptation to environment best, 

 hence the reason for the gradually increasing circles. The 

 effect is certainly strikingly beautiful. The circles stand out 

 clearly in a well-cropped lawn some four days after a rain. 

 — /. A. Nieuivland. 



Speed of Diatoms. — Nearly everyone who has peeped 

 through a microscope has seen one or more species of diatoms. 

 The cell-walls of glass most beautifully and delicately marked 

 make them prime favorites with the microscopist, indeed one 

 species of diatom is said to be used in testing lenses. Not- 

 withstanding their glassy cell-v/alls, diatoms are really plants, 

 though to see them moving about on the slide of a microscope 

 the hasty observer might jump to the conclusion that they are 

 animals. The movements of these plants have often provoked 

 speculation. Though seemingly rather lively it must be re- 

 membered that the microscope magnifies the motion as well 

 as the plant. The progress of the diatom is therefore said to 

 be relatively slow. Just how slow it is has been figured out 

 by T. Chalkley Palmer in the "Proceedings of the Delaware 

 County Institute of Science." Comparing the diatom, with 

 a man. he finds that to equal the diatom man would have to 

 go at the rate of more than 23 miles an hour and drag with 

 him 2520 pounds of extra weight ; or if he should devote the 

 energy necessary to move this weight to locomotion alone, he 

 would have to strike a gait of more than 450 miles an hour. 

 Evidently the diatom is not so slow after all. 



