272 



LECTURE XVI. 



of the Stem only began afterwards, and then continued for fourteen days. During 

 the first few days the expulsion of water was copious: later on it gradually 

 diminished. On the whole, however, 1061 cubic centimetres of water were expelled 

 in thirteen days — a quantity which was at least three times as large as the volume of 

 the whole root-stock ; whence follows without further remark that the escaped water 

 could not possibly have been previously contained in the root-stock, but must have 

 been taken up only during the outflow^one of the most fundamental facts connected 

 with this subject. 



The circumstances under which the outflow of water takes place, will best be 

 made evident if I here put together in the form of a table the observations made, 

 at least for the first six days. It is only to be noticed that the letters n, e, m, a signify 

 noon, evening, morning, and afternoon respectively ; tbe numbers in the fifth column 

 are obtained by division of the quantity of water discharged in the given period of 

 time by the corresponding number of hours. 



HELIANTHUS ANNUUS. AUGUST, 1881. 



What is conspicuous at once in our table, and has been known for a long time, 

 are the continual fluctuations in the quantity of water hourly discharged. These take 



