AMERICAN NATURALIST 



By E. L. Gbbgory. 



(Continued from p. 217.) 



The nature of the experiments will be best understood 

 by a brief statement of the outlines of his theory in regard to 

 the processes by which the water is carried up. He regards 

 the ducts, and to a certain extent, the tracheids, as reservoirs 

 into which the water is passed from the absorbing cells. 

 These ducts, except it may be in a certain period of the year 

 when the so-called root pressure is taking place, are never 

 filled with water but with alternating columns of air and 

 water. All who are at all familiar with this subject will remem- 

 ber that this was the first argument against the new theory. 

 How could the water pass up in the cell lumena when these 

 were not themselves filled? It is claimed now that this very 

 fact is the one which admits of such a possibility. That is, 

 these alternating columns make a combination known as the 

 Jaminschen chain, from the name of the Frenchman, Jamin, 

 who was the first to compute the force exerted by a chain of 

 air and water columns in a capillary tube. Such an apparatus 

 was called by his name, and the discovery of such a system of 

 chains in the ducts and tracheids of woody tissue has been the 

 strong point in the new water theories. The manner of action 

 of this chain mav be seen at once, the meniscuses acting as 

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