"To this I answer, that do but intensly observe any one of the former spots or clouds, and you shall see it go quite along from the tail to the head, keeping alwayes an equal distance from the precedent and subsequent spot: so that it is far more ingenious to believe it to be a gale of Animal Spirits, that, moving from her head along her back to her tail, and thence along her belly to her head again, is the cause of her progressive motion."
— Power, Henry (1623-1668)
Henry Power, Experimental Philosophy, in Three Books Containing New Experiments Microscopical, Mercurial, Magnetical: With Some Deductions, and Probable Hypotheses, Raised from Them, in Avouchment and Illustration of the Now Famous Atomical Hypothesis. (London: Printed by T. Roycroft, for John Martin and James Allestry, 1664). <Link to EEBO-TCP>