_Fig. 8._ Is a Number of Jet d'Eaus, or Fountains, made by condens'd Air, in a large Copper Vessel C D, pressing on the Surface of Water at the Bottom of the Vessel; into which Water a hollow Brass Pipe is immers'd. For if there be then a Stopcock at G, to open or shut the hollow Pipe at Pleasure; and several smaller Pipes at I K, communicating therewith, turning upon Balls or Joints, and plac'd in Order, we shall have a very pleasant Set of these _Jet d'Eaus_, or Fountains; all whose Water will be caught by the Bason A B, which Water may be again let into the Vessel C D, by unscrewing the Pillar in the Center of the Bason. [[Plate VI. ― I. Senex sculp.^t]] PNEUMATICKS. 20 An Explication of the Sixth PLATE. This Plate is in Reality but one compound Instrument or Apparatus, for trying the Electricity of Glass, and its Luminousness, when put into Motion, and rubb'd upon to heat it. Wherein B C is a Wheel, with its String A B C. D E is a Sphere of Glass, whose Air has been drawn out by the Air-Pump: This is turned round by the former Wheel-string at A. F is a Stopcock, whereby the Air is exhausted, and may be readmitted at Discretion. In _Fig. 1._ K L M is an Arch with Threads of Cruel or Yarn upon it, as they hang about the Glass D E, (here represented by a smaller Circle within the Arch) before it is turned round or heated by rubbing. _Fig. 2._ G H I is the same with the former; only the Threads are here represented as they hang at the Beginning of the turning round of the Globe, before it be heated by Friction; being plainly bent one way, by a Wind arising from that Convolution. _Fig. 3._ N P O is the same; only with the Threads pointing towards the Sphere, or its Center, when the Arch is in an upright Posture, and some of the Threads hang partly downwards, and this upon the Spheres being heated sufficiently. _Fig. 4._ Q S R is the same, with its Threads pointing the same way, though in a downward Posture, when some of the Threads thereby are forc'd to stand erect. _Fig. 5._ T U is a Circular Arch, in an horizontal Position, when the Threads point towards the same Center, in the same horizontal Plain.