[ ^5r ] 



pared, becaufe the fame degrees of deficcation could not be 

 exadlly afcertained, and becaufe many of the fibrillas of the 

 roots of the tree muft have remained in the earth after the 

 tree was taken out of the veffel, and thefe muft have prevented 

 the true lofs of earth from being perceived. Secondly, that the 

 earthen veffel muft have frequently abforbed water impreg- 

 nated with whatever fubftance it might contain from the fur- 

 rounding earth in which it was inferted, for unglazed earthen 

 vefTels eafily tranfmit moifture, ift Hales 5, and Tiller's Mem. 

 Par. 1772, page 298, 304, 8vo. Thirdly, as it appears that the 

 pot was funk in the earth and received rain water, it is pro- 

 •bable that diftilled water was feldom ufed. 



These circumftances being confidered, it will eafily be made 

 to appear that the rain water abforbed by the tree contained 

 as much earth as the tree can be fuppofed to contain. 



First, The willow increafed in weight 1641b. in five years, 

 that is, at the rate of 2,71b. nearly per month, and it being an 

 aquatic it cannot be fuppofed to pafs lefs than its own weight of 

 water each day during the fix vegetating months. In the firft 

 month therefore it abforbed and pafled 5x30=1 5olb. and as each 

 pound of rain water contains -i- gr. of earth, 50 grs. of earth 

 muft have been depofited in the plant, and allowing no more 

 than 50 grains for the depofite of each of the fix months, we 

 ftiall have 50x6=300 for the depofite of the firft year ; but at the 

 end of the firft year the plant gains an acceflion of 321b. there- 

 fore 



