I chose several _Glass Vials_, that were all, as near as possible, of the same shape and bigness. After I had put what Water I thought fit into every one of them, and taken an Account of the weight of it, I strain'd and ty'd over the Orifice of each Vial, a Piece of Parchment, having an hole in the middle of it, large enough to admit the Stem of the Plant I design'd to set in the Vial, without confining or streightning it, so as to impede its _Growth_. My Intention in this, was to prevent the inclosed Water from evaporating, or ascending any other way than only through the Plant to be set therein. Then I made choice of several Sprigs of Mint, and other Plants, that were, as near as I could possibly judge, alike fresh, sound, and lively. Having taken the weight of each, I placed it in a Vial, order'd as above; and as the Plant imbib'd and drew off the Water, I took care to add more of the same from time to time, keeping an Account of the weight of all I added. Each of the Glasses were, for better distinction, and the more easie keeping a Register of all Circumstances, noted with a different Mark or _Letter_, _A_, _B_, _C_, _&c._ and all set in a Row in the same Window, in such manner that all might partake alike of _Air_, _Light_, and _Sun_. Thus they continued from _July_ the Twentieth, to _October_ the Fifth, which was just Seventy Seven Days. Then I took them out, weigh'd the Water in each Vial, and the Plant likewise, adding to its weight that of all the Leaves that had fallen off during the time it stood thus. And Lastly, I computed how much each Plant had gain'd; and how much Water was spent upon it. The Particulars are as follow. (A.) _Common Spear-Mint_, set in _Spring-Water_. The Planted weighed when put in, _July_ 20. just 27 Grains; when taken forth, _October_ 5. 42 Grains: So that in this space of 77 Days, it had gained in weight 15 Grains. The whole Quantity of Water expended, during these 77 Days, amounted to 2558 Grains. Consequently the weight of the Water taken up, was 170-8/15 times as much as the Plant had got in weight. (B.) _Common Spear-Mint_, _Rain-Water_. The Mint weigh'd, when put in, Gr. 28¼; when taken out Gr. 45¾, having gain'd in 77 Days Gr. 17½. The Dispendium of the Water Gr. 3004, which was 171-22/35 times as much as the Plant had received in weight. (C.) _Common Spear-Mint_, _Thames-water_. The Plant when put in, Gr. 28, when taken forth, Gr. 54. So that in 77 Days it had gained Gr. 26. The Water expended, amounted to Gr. 2493. which was 95-23/26 times as much as the additional weight of the Mint. (D.) _Common Solanum_, or _Night-shade_: _Spring-water_. The Plant weigh'd, when put in, Gr. 49; when taken out, 106; having gain'd in 77 Days 57 Gr. The Water expended during the said time, was 3708 Gr. which was 65-3/57 times as much as the Augment of the Plant.