And this will make probable my next Position, That _the parts of the Glass are under a kind of tension or flexure, out of which they indeavour to extricate and free themselves_, and thereby all the parts draw towards the Center or middle, and would, if the outward parts would give way, as they do when the outward parts cool leisurely (as in baking of Glasses) contract the bulk of the drop into a much less compass. For since, as I proved before, the Internal parts of the drop, when fluid, were of a very rarified Texture, and, as it were, tos’d open like a Lock of Wool, and if they were suffered leisurely to cool, would be again prest, as it were, close together: And since that the heat, which kept them bended and open, is removed, and yet the parts not suffered to get as neer together as they naturally would; It follows, that the Particles remain under a kind of _tension_ and _flexure_, and consequently have an indeavour to free themselves from that _bending_ and _distension_, which they do, as soon as either the tip be broken, or as soon as by a leisurely heating and cooling, the parts are nealed into another posture. And this will make my next Position probable, that _the parts of the Glass drops are contignated together in the form of an Arch_, cannot any where yield or be drawn inwards, till by the removing of some one part of it (as it happens in the removing one of the stones of an Arch) the whole Fabrick is shatter’d, and falls to pieces, and each of the Springs is left at liberty, suddenly to extricate it self: for since I have made it probable, that the internal parts of the Glass have a contractive power inwards, and the external parts are incapable of such a Contraction, and the figure of it being spherical; it follows, that the superficial parts must bear against each other, and keep one another from being condens’d into a less room, in the same manner as the stones of an Arch conduce to the upholding each other in that Figure. And this is made more probable by another Experiment which was communicated to me by an excellent Person, whose extraordinary Abilities in all kind of Knowledg, especially in that of Natural things, and his generous Disposition in communicating, incouraged me to have recourse to him on many occasions. The Experiment was this: Small Glass-balls (about the bigness of that represented in the _Figure &._) would, upon rubbing or scratching the inward Surface, fly all insunder, with a pretty brisk noise; whereas neither before nor after the inner Surface had been thus scratcht, did there appear any flaw or crack. And putting the pieces of one of those broken ones together again, the flaws appeared much after the manner of the black lines on the Figure, _&._ These Balls were small, but exceeding thick bubbles of Glass, which being crack’d off from the _Puntilion_ whilst very hot, and so suffered to cool without nealing them in the Oven over the Furnace, do thereby (being made