Experimental notes of the mechanical origine or production of fixtness.

CHAP. V. (Book 5)

ANother particular, I am unsatis∣fied with in the Hypothesis of Alcali and Acidum, is, that 'tis in divers cases either needless or useless to ex∣plain the Phaenomena of Qualities, there being several of these produ∣ced, destroyed, or altered, where there does not appear any accession, recess, or change of either of those two Principles; as when fluid water by hard beating is turn'd into consistent froth, and when transparent red Co∣ral is, barely by being beaten and sifted finely, changed into a white and opacous powder; and as when a very flexible piece of fine silver being hammer'd is brought to have a brisk spring, and after a while will, instead

of continuing malleable, crack or cleave under the hammer; and as when (to dispatch and omit other in∣stances) a sufficiently thin leaf of Gold, held between the Light and the Eye, appears green.

Another thing (of kin to the for∣mer,) that I like not in the Doctrine of Acidum and Alcali, is, that though the Patrons of it, whilest they would seem to constitute but two Principles, are fain (as I lately intimated) to make I know not how many differing sorts of Acids, besides some variety of Alca∣lies; yet their Principles are too few and narrow to afford any satisfactory explication of the Phaenomena. For I fear, 'twill be very difficult for them to give a Rational Account of Gravi∣ty, Springiness, Light, and Emphatical Colours, Sounds, and some other Qualities that are wont to be called manifest; and much more of several that are confest to be occult, as Ele∣ctricity, and Magnetism; in which last I see not, how the affirming that

there is in the Magnet an Acid and an Alcali, and that these two are of contrary Natures, will help to explain, how a Load-stone does, as they speak, attract the same end of a poised needle with one of its Poles, which 'twill drive away with the other, and determine that needle when freely placed, to point North and South, and enable it to communicate by its bare touch the same Properties, and abun∣dance of other strange ones, to ano∣ther piece of Steel. But I forbear to alledge particular Examples refer∣rable to the several Qualities above∣mentioned, whether manifest or hid∣den, because that in great part is al∣ready done in our Notes about parti∣cular Qualities, in which 'twill appear how little able the employing of Al∣cali and Acidum will be to afford us an account of many things. And though I enlarge not here on this objecti∣on, yet I take it to be of that impor∣tance, that, though there were no o∣ther, this were enough to shew that

the Hypothesis that is liable to it, is Insufficient for the explication of Qualities; and therefore 'twill not I presume be thought strange that I add, that, as for those that would ex∣tend this narrow Chymical Doctrine to the whole object of Natural Philo∣sophy, they must do more than I ex∣pect they will be able before they can make me their Proselyte, there being a multitude of Phaenomena in nature (divers whereof I elsewhere take no∣tice of in reference to the Chymists Philosophy) in which what Acidum and Alcali have to do, I confess I do not understand.