SECT. I. INTRO-SUSCEPTION. 9 1 



of almost any species of moss that has been some 

 time gathered, or long exposed to drought, so as to 

 have had its leaves shrivelled up. The moisture 

 will immediately begin to ooze through the epider- 

 mis, and the plant to resume its original form and 

 verdure. 



But has any of the moisture thus absorbed passed By the 

 through the root ? If the bulb of a hyacinth is 

 placed on the orifice of a glass bottle filled with 

 water, so as that the radicles only shall be immersed, 

 the water is imperceptibly exhausted, and the plant 

 grows : the moisture must consequently have passed 

 through the root. The following experiment of 

 Hales proves not only the fact, but also the extra- 

 ordinary energy of the absorbent power of the root. 

 Having laid bare the root of a pear tree half an inch 

 in diameter, and luted to it a tube of glass, one 

 inch in diameter and eight inches long, to which 

 was luted also another tube a quarter of an inch in 

 diameter and 18 inches long, he filled both with 

 water, and immersed the extremity in a cistern of 

 mercury. The result was, that the absorption of 

 water by the root was so rapid that the mercury 

 rose eight inches in the space of six minutes.* 



But moisture is absorbed also by the leaves as Bytheleaf. 

 well as root. Du Hamel cut off several branches 

 from several trees of different species, and covered 

 the surface of the section with mastic. The conse- 

 quence was that the branches soon began to exhibit 

 * Veg. Star. Exper. xxi. 



