Note Book VIII. Chap. 4. Note (f) — BOOK VIII.

[f] There are, (I imagine,) divers Animals, as well as Spiders, that have some Way of Conveyance, as little known to us, as that of Spiders formerly was. Thus the Squillulæ, pulices Arborescentes, and microscopical Animalcules of the stagnating Waters, so numerous in them, as to discolour sometimes the Water, and make them look as if they were tinged Red, Yellow or Green, or cover’d with a thick green Scum; all which is nothing but Animalcules of that Colour. That these Creatures have some Way of Conveyance, I conclude: because most stagnating Waters are stock’d with them; new Pits and Ponds, yea, Holes and Gutters on the Tops of Houses and Steeples. That they are not bred there by æquivocal Generation, every ingenious, considering Philosopher will grant; that they have not Legs for travelling so far, is manifest from Inspection: And therefore I am apt to think, that they have some Faculty of inflating their Bodies, or darting out Webs, and making their Bodies buoyant, and lighter than Air; or their Bodies, when dry, may be lighter than Air, and so they can swim from Place to Place; or the Eggs of such as are oviparous, may be light enough to float in the Air. But then the Viviparous, (as my late ingenious Friend, Mr. Charles King, shew’d me the Pulices aquat. arbores. are; these I say,) can’t be this Way accounted for. The Cause of these latter Suspicions was, that in the Summer Months, I have seen the Pulices arbores. and the green Scum on the Waters, (nothing but Animalcules, as I said,) lie in a Manner dry on the Surface of the Waters; at which Time, (as I have shewn in Book IV. Chap. 11. Note (n),) those Animalcules copulate; and perhaps, they may at the same Time change their Quarters, and seek out new Habitations for their numerous Offspring, as well as themselves.