384 PHILOSOPHICAL TRANSACTIONS. [aNNO iSgQ. 



in the same spring ; tlie water, as it drains and passes tiirough tlie strata of stone, 

 earth, &c. taking up such loose mineral corpuscles, as it meets with in the 

 pores and interstices of those strata, and bringing them on with it quite to the 

 spring. All water whatever is much charged with the vegetable matter, this 

 being fine, light, and easily moveable. I'or the mineral, the water of springs 

 contains more of it than that of rivers, especially when at distance from their 

 sources, and that of rivers more than the water that falls in rain. Any one 

 who desires further satisfaction in this may easily obtain it, if he only put 

 water into a clear glass phial, stopping it close to keep dust and other exterior 

 matter out, and letting it stand without stirring it for some days ; he will then 

 find a considerable quantity of terrestrial matter in the water, however pure 

 and free it might appear when first put into the phial. He will in a very short 

 time observe the corpuscles that were at first, while the water was agitated and 

 kept in motion, separate, and hardly visible, by degrees, as it is more still and 

 at rest, assembling and combining together : by that means forming somewhat 

 larger and more conspicuous moleculae. Afterwards he may behold these 

 joined and fixed to each other, and thus forming large thin masses, appearing 

 like nubeculas, or clouds in the water; which grow more thick and opaque, by 

 the continual appulse and accretion of fresh matter. If the said matter be 

 chiefly of the vegetable kind it will be sustained in the water, and discover at 

 length a gieen colour : becoming still more and more green as the matter 

 thickens and increases. But if there be any considerable quantity of mere 

 mineral matter in the water, this, being of a greater specific gravity than the 

 vegetable, as its particles unite and combine to form moleculae, their impetus of 

 gravity surpasses that of the resistance of the water, and a great deal of it 

 subsides to the bottom ; and frequently entangling with the vegetable nubeculaG, 

 forces them down along with it. 



Now the question is, to which of these, the water, or the earthy matter sus- 

 tained in it, vegetables owe their growth and increase. For deciding which, 

 the following experiments may afford some light, having been made with due 

 care and exactness. 



I chose several glass phials, all as near as possible of the same shape and 

 size. After putting what water I thought fit into every one of them, and 

 taking an account of its weight, I strained and tied close over the orifice of 

 each phial a piece of parchment, having a hole in the middle, large enough to 

 admit the stem of the plant I designed to set in it, without straitening it so 

 as to impede its growth. My intention in this was to i)rcvent the enclosed water 

 from evaporating, or ascending any other way than through the plant. Then 

 making choice of several sprigs of mint, and other plants, that were as near 



