British Library MS. Sloane 480. Parchment. Duodecimo. 162 folios. 15th Century. At one time belonged to Johannis Postylthwayt, de Pomfret, co. Ebor., later to Francis Bernard and numbered 124. 2. 'Liber de quinta essentia', or 'The mirour of Filosofie,' in two books; the first, 'of the consideracioun of the fythe beyng', the other, 'of general remedies.' f.26. Begins: 'Gracious Kyng Salamon in ye 7 chapiter of Sapience sayde, God gaf to me ye trew science', etc. Ends: 'than the foresaid noble fifth beyng, or ellys in hys absence brennyng water.' 'Here endith this tretys of soveryne medycines de quinta essencia.'