_Virginia_, generally twice in the Year, Spring and Fall, at certain Spring-Tides, the most of the Cattle will set on gadding, and run, tho' it be twenty or thirty Miles, to the River to drink the Salt Water, at which time there's scarce any stopping of them; which the People know so well, that if about those times their Herds are stray'd from their Plantations, without more sollicitation they go directly to the Rivers to fetch them home again. As for the Waters in the Springs in general, they are, I think, somewhat more eager than those in _England_. In that I have observed, they require some quantity more of Malt to make strong Beer than our _English_ Waters, and will not bear Soap. I have try'd several by infusing of Galls, and found little difference in the Colours, turning much what the Colour of common Sack in Taverns. I tried two Wells at Col. _Birds_, by the Falls of _James River_, several Wells near _James Town_, some Springs in the _Isle of Wight County_: There's a Spring in the _Isle of Wight_, or _Nanzamond County_, vents the greatest Source of Water I ever saw, excepting _Holy-well in Wales_, but I had not opportunity to make Experiments thereof. I tried likewise some Springs on the Banks of _York River_, in _New Kent_ and _Gloucester County_, but found them vary very little as to Colour. I could not try any thing as to their specifick Gravity, having neither Aquapoise, nor those other Glasses I had contrived peculiarly for making such Experiments, they being all lost with my other things. I had Glasses blown would hold about five Ounces, others about ten Ounces, with Necks so small, that a Drop would make a considerable Variation; with these I could make much more critical and satisfactory Observations as to the specifical Gravity of Liquors, having critical Scales, than by any other way yet by me tried. I used this method to weigh Urines, which Practice I would recommend to the Inquisitive and critical Physicians. I had made many Observations hereof, but all Notes were likewise lost with my other things. Yet I have begun afresh; for there are more signal Variations in the Weights of Urines than one would at first imagin; and when the Eye can discover little, but judge two Urines to be alike, they may be found to differ very much as to Weight. By Weight I find Observations may be made of Affections in the Head, which rarely make any visible Alterations in the Urine. I have found two Urines not much unlike differ two and twenty Grains in the quantity of about four or five Ounces: But let them that make these Essays weigh all their Urines when cold, lest they be thereby deceiv'd. But to return to the Spring Waters in _Virginia_. There's a Spring at my Lady _Berkley's_, called _Green-Spring_, whereof I have been often told, so very Cold, that 'tis dangerous drinking thereof in Summer-time, it having proved of fatal Consequence to several. I never tried any thing of what Nature it is of.