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PLANT PHYSIOLOGY 



The Klinostats so far described are either normal or precision forms, 

 but a number of adapted types have been invented. Thus aside from a crude 

 Klinostat centrifuge, made from clock works, described by SWEZEY in the 

 Botanical Gazette, 16, 1891, 147, STEVENS has described a simple form run. 

 by a water-motor (Botanical Gazette, 20, 1895, 92); STONE gives one run 

 by clockwork (Botanical Gazette, 22, 1896, 259), and I have myself de- 

 scribed a good form, constructed from the works of a powerful clock, in 

 the Botanical Gazette, 27, 1899, 258, an instrument which, by the way, 



FIG. 64. FRAME FOR DEMONSTRATION OF GEOTROPISM; X. 



Explanation in text. The lower counter-weight should be shown hanging on a wire loop 

 which turns on the frame. 



would be much improved by using a box of wire netting instead of the crys- 

 tallizing dish. Still simpler arrangements approaching the make-shift char- 

 acter, and revolving but once an hour (which is sufficient for some of the 

 simplest uses), have been described by OSTERHOUT, 91, by STEVENS in his 

 "Introduction to Botany" (Heath & Co., 1902), 25, and by others. 



The limitations of Klinostats, and the proper principles in their con- 

 struction and use, have recently been discussed by NEWCOMBE in Science 

 20, 1904, 376, and by VAN HAKREVELD in his paper cited above. 



