Heat and Cold, according to your _Authors_ opinion, are made by Dilation and Contraction: for says he,[1] _When the Motion of the ambient æthereal substance makes the spirits and fluid parts of our bodies tend outwards, we acknowledg heat, but by the indeavour inwards of the same spirits and humors we feel cold: so that to cool is to make the exterior parts of the body endeavour inwards, by a motion contrary to that of calefaction, by which the internal parts are called outwards. He therefore that would know the cause of Cold, must find by what motion the exterior parts of any body endeavour to retire inwards._ But I desire you to consider, _Madam_, that there be moist Colds, and dry Heats, as well as dry Colds, and moist Heats; wherefore all sorts of Cold are not made by the retyring of parts inwards, which is contraction or attraction; neither are all sorts of Heat made by parts tending outwards, which is dilation or rarefaction; for a moist cold is made by dilation, and a dry heat by contraction, as well as a moist heat is made by dilation, and a dry cold by contraction: But your _Author_ makes not this difference, but onely a difference between a dilated heat, and a contracted cold; but because a cold wind is made by breath blown thorow pinched or contracted lips, and an hot wind by breath through opened and extended lips, should we judg that all heat and cold must be made after one manner or way? The contracted mouth makes Wind as well as the dilated, but yet Wind is not made that way, as heat and cold; for it may be, that onely the air pressed together makes wind, or it may be that the corporeal motions in the air may change air into wind, as they change water into vapour, and vapour into air; or it may be something else that is invisible and rare, as air; and there may be several sorts of wind, air, heat, cold, as of all other Creatures, more then man is capable to know. As for your _Authors_ opinion concerning the congealing of Water, and how Ice is made, I will not contradict it, onely I think nature hath an easier way to effect it, then he describes; Wherefore my opinion is, that it is done by altering motions; as for example, the corporeal motions making the figure of water by dilation in a Circle figure, onely alter from such a dilating circular figure into a contracted square, which is Ice, or into such a contracted triangle, as is snow: And thus water and vapour may be changed with ease, without any forcing, pressing, raking, or the like. The same may be said of hard and bent bodies; and of restitution, as also of air, thunder and lightning, which are all done by an easie change of motion, and changing into such or such a figure is not the motion of Generation, which is to build a new house with old materials, but onely a Transformation; I say a new house with old materials; not that I mean there is any new Creation in nature, of any thing that was not before in nature; for nature is not God, to make