The proposition, and demonstration, were fairly written on a thin wafer, with ink composed of a cephalic tincture.
The artist himself was at that time busy upon two great designs; the first, to sow land with chaff, wherein he affirmed the true seminal virtue to be contained, as he demonstrated by several experiments, which I was not skilful enough to comprehend.
He said, "that new systems of nature were but new fashions, which would vary in every age; and even those, who pretend to demonstrate them from mathematical principles, would flourish but a short period of time, and be out of vogue when that was determined."
He had performed many eminent services for the crown, had great natural and acquired parts, adorned with integrity and honour; but so ill an ear for music, that his detractors reported, "he had been often known to beat time in the wrong place;" neither could his tutors, without extreme difficulty, teach him to demonstrate the most easy proposition in the mathematics.
There are no more uses of "demonstrate" in the book.