British Library MS. Sloane 3730. Paper. Quarto. 12 folios. 17th Century. 'Questions and answers concerning the Philosophers' Stone; the coppy whereof I had from my Lord Sheffield at Hammersmith, August the 1st, 1623'. Written 3 April, 1679. Begins: 'Question. First shewe me in what thing, of what thing, or by what thing is the multyplycation of mettals to be made'.