Page:Philosophical Transactions - Volume 003.djvu/230

 47. Of an attempt made to measure the Force of the Spring of included Air, and examine a Conjecture of the difference of its strength in unequally broad-mouth'd Vessels.

48. About an easie way of making a small quantity of included Air raise in the exhausted Receiver 50 or 60 pounds, or a greater weight.

49. Concerning the Weight of Air, and the estimating thereof, both by the help of a seal'd Bubble, and by weighing the Receiver it self: together with an Advertisement of the variation of the Gravity of the Air, and that, by Experiments made at different times or places, there are obtain'd different proportions betwixt It and Water,

50. About the disjoining of two Marbles (not otherwise to be pull'd asunder without a great weight) by with-drawing the Pressure of the Atmosphere.

Which Experiments are, where 'twas necessary, illustrated with Figures, to the number of 30 in 8 Plates.

The whole is concluded with some Notes and Trials about the Atmospheres of Consistent Bodies (here below) shewing, that even Hard and Solid Bodies (and some such, as one would scarce suspect) are capable of emitting Effluvia, and so of having Atmospheres; which is prov'd first a priori, both by the Atomical and Cartesian Hypothesis; and then demonstrated by particular Examples in several Bodies: where, instancing in those, that are most fixt, the Author examines the Argument of DesCartes against Electrical emanations, drawn from the fixedness of Glass.

Whereunto are subjoined not only some Observations about the Electricity of Bodies, as that of Amber by the Sun, and that of Glass by the Heat of the Fire; but also some Considerations, that may induce us to believe, that very many other Bodies, not yet discover'd to do so, emit their Effluviums.

N this Curious and Experimental Treatise the Reader will First meet with some Animadversions upon Dr. Witties Tract of the Scarbrough-Spaw; our Author affirming, that upon Rh