Page:Philosophical Transactions - Volume 002.djvu/46

 his Fundus subterram, and improved and first brought into use here, divers years agoe, by the Noble R. Boyle, who also, as himself informed the Publisher, hath in some of his Writings, yet unpublisht, set down a full Description thereof.

It is such a Glass-Tube as is represented by Fig. 7. blown at a Lamp, and poised in good common Water by putting Quick-silver into it, until it sink so low, that nothing appear above the Superficies of the Water, but the Top; which done it is to be sealed up, and to be graduated on its side, into what parts you please; which may be done with a Diamond. And then, being put into any Water to be weighed, it will, by its more or less sinking into it, shew the differences of the Waters gravity.

O perform this, let there be made a Square Wooden Bucket (such as C in Fig. 8.) whole bottoms E E are to be so contrived, that the weight A do sink the Iron B (to which the Bucket C is fastned by two Handles D D, on the ends of which are the moveable bottoms or Valves E E) and thereby draws down the Bucket, the resistance of the Water keeps up the Bucket in the posture C, whereby the Water hath-a-clear thorow-passage all the while it is descending; whereas as soon as the Bucket is pulled upwards by the Line F, the resistance of the Water to that motion, beats the Bucket downward, and keeps it in the posture G; whereby the included Water is preserved from going out, and the Ambient Water kept from getting in.

By the advantage of which Vessel, or such like, you may come to know the Degrees of Saltness of Sea-Water, according to its nearness to the Top or Bottom; or rather, the Constitution of the Sea-Water in several Depths of several Climates: Likewise, whether in some places of the Sea, there be any sweet Water at the Bottom; the Affirmative whereof is to be met with in the East-Indian Voyages of Van Linschoten, who pag. 16 of that Work, as 'tis Englished, records, that in the Persian Gulf, about the Isle of Baharem, fetch up with certain Vessels (which he de-