Hydraulics.

The abovementioned * prodigious Raft'faction of a small Quantity of Waterbe made very sensible by the Æolifwhose Nature and Use in- the Producti 0l lof a continual and most powerful Bias VSteam y or vaporous Windy is a Phanome^equally curious and surprising, as will as"pear from the Experiment (LXXXIII.)

V. Th ^

whence the specific Gravity of elastic Steam is to ^of Air as 40 to 220, or as 1 to 5 nearly ; andthat of Air is to Water as 1 to 860, therefore the fp ecific Gravity of Steam is to that of the Water, as 1 c °

, 860 X 5 = 4300. >

13. Again, since t S of an Ounce of Water expelsnear 925 cubic Inches of Air; then one cubicof Water (which weighs feVe of an Ounce Troy) vf,expel about 4630 cubic Inches, but Mr. Payne4000 for a Standard in Calculation. .

(LXXXIII.) 1. The Æolipile is an Instrum®contriv’d for Use, as well as Jucundity. It has jName from the Fable of Æolus, the God ofand Tempests, who was defcrib’d as having his flace in the Caves, and locking up the Winds inHollows of the Mountains. The Word literally >n^preted is, the Gates of Æolus (’AioXts tst-jXch) bec^ ^of the Similitude of its Effect:. For it consists y jjCopper globular Body, in which is inserted aNeck or Pipe, with a very small Orifice, from wh^(when the Vessel has Water in it, and heated) a ^pour issues with prodigious Violence, Impetuosity? *Force, and blows m the Manner of a terrible temp elous Wind. ' £S)

PI.XXL 2. The Body of this Instrument consists of two

Fi». 7. A and B folder’d together with hard Solder, to en ,

0 a great Heat of Fire. On. the upper Part is ass 0 ' - s

der’d the Pipe C D, whose Orifice or Hole at f (jabout the 40th or 50th Part of an Inch in Di aIIie . pThe Way to fill it with Water is, to set it first? ^ 0 ^tempty, on the Fire, which will heat it, and drive ^