transmute Metals, make Butter and Cheese without Milk; and (as their own Ballad hath it) make Leather without Hides ) by asserting the usefulness of even all your preparatory and luciferous Experiments, being not the Ceremonies, but the substance and principles of useful Arts. For, I find in Trade the want of an universal measure, and have heard Musicians wrangle about the just and uniform keeping of time in their Consorts, || and therefore cannot with patience hear, that your Labours about Vibrations, eminently conducing to both, should be slighted, nor your Pendula  called Swingswangs with scorn. Nor can I better endure, that your Exercitations about Air should be termed fit imployment only for Airy Fancies, and not adequate Tasks for the most solid and piercing heads. This is my Opinion concerning you: and although I am none of your number, nor have the least ambition to be so, otherwise than to become able
The first, fifteenth and seventeenth stanzas are:
If to bee rich, & to be learnd
Be every nations chiefest glory,
How much are Englishmen concerned
Gresham to celebrate in story
Who built th' Exchange t' inrich the Citty
And Colledge founded for the Witty.
A second hath described at full
The Philosophy of making Cloth
Tells you, what Grass doth make course Wooll
And what it is that breedes the Moth
Great learning is 'ith art of Clothing
Though vulgar People think it nothing.
A new designe how to make Leather
A third Collegiate is now scanning
The question's most debated whether
Since without Barke there may be Tanning
Some cheaper way may not be tryed
Of making Leather without a Hyde.
- A ballad of twenty-eight stanzas, "In praise of the choice Company of Philosophers and Wittes who meet on Wednesdaies weekely at Gresham Colledge," is in Ashmole MS. 36, 37, f. 310-312.
- Petty was among those interested in the experiments upon pendulums which were made in January, 1662. Birch, i. 70, 74, also 46, 53.