ON WATER AND WATERING PLANTS. 281 



« Upon immersing the lower end of it into the water, this (by 

 little and little) ascended quite to the orifice of the tube : and yet 

 in all the fifty six days that it stood thus, a very inconsiderable 

 quantity of water had gone off, viz. scarcely twenty grams, though 

 the sand continued moist up to the top until the very last 



The water had imparted a green tincture to the sand, quite 

 to the very top of the tube : and in the phial it had precipitated a 

 greenish sediment mixed with black. 



Pretty much of the green substance, described above, ad- 

 hered to the bottom and sides of the tube, as far as it was im- 



mprsGu 



Other like tubes he filled with cotton,; lint, pith of elder, and 

 several other porous vegetable substances ; setting some of them 

 in clear water, others in water tinged with saffron, cochineal, &c. 

 and made several other trials, to give a mechanical representation 

 of the motion and distribution of the juices in plants, and some 

 other phsenomena observable in vegetation. 



Several plants being also set in phials, Q, R, S, &c, were 

 ordered after the same manner with those above, in the following 

 colder months ; these throve not near so much, nor did the water 

 ascend in nigh the quantity it did in the hotter seasons, m which 

 the before cited trials were made. 



From these experiments, the observations proceed. 



Observation 1. In plants of the same kind, the less they are 

 in bulk, the smaller quantity of the fluid mass in which they are 

 set is drawn off; the dispendium of it, where the mass is of 

 equal thickness, being pretty nearly proportioned to the bulk of 



the plant. . , 



Thus the plant in the glass marked A, that weighed twenty- 

 seven grains, drew off but two .thousand five hundred and fifty- 

 eight grains of the fluid; and that plant in B, that weighed 

 twenty^ight and one-fourth, took up bu four thousand and 

 four grains of the fluid ; whereas that plant in H, which weighed 

 one hundred and twenty-seven grains, took up fourteen thou- 

 sand one hundred and ninety grains of the liquid mass. 



The water seems to ascend np the vessels of plants much 

 after the same manner as up a filter ; and it „ no strange thing 

 that a larger filter should draw off more water thanalesser one 

 or a plan! that has more and larger vessels, should take up 

 greater share of the fluid in which it is set. than one that ha* 

 t wer and smaller ones can. 



fe VOL. V. HH 



