In the study of a composite work, such as the _Liber Luminis_ is thus declared to be, our first problem is naturally to determine and separate the original text from the additions which have been made to it. Which then are those parts of the _Liber Luminis_ that represent the _Secreta Naturae_? Very fortunately the volume where the _Liber Luminis_ is found contains another treatise that throws considerable light on the matter. This is the _Liber Dedali Philosophi_. The correspondences between that book and the _Liber Luminis_ are so many, close, and verbal, that it is evident both have borrowed from the same source. This source can hardly have been other than the _Secreta Naturae_, so that a comparison of these two books such as is attempted in the Appendix[128] should go far to determine what that hitherto unknown text was. The question of the chemical doctrine contained in the _Secreta_ is an interesting one, and we shall return to it, but meanwhile, let us observe that the _Liber Luminis_ contains hints which seem to carry us further still, and throw some light upon the source from which the _Secreta_ was itself derived. One of the authors quoted is a certain ‘Archelaus.’ Now there was a veritable chemist of this name who lived during the fifth century. This author wrote a treatise on his art in Greek verse. In later times his name seems to have become common property, as did so many others distinguished in alchemy, and to have been freely used by some who wrote long after his day. Thus the Riccardian manuscript itself contains no less than three books ascribed to this author: the _Liber Archelai Philosophi de arte alchimiae_,[129] called also in the margin _Practica Galieni in Secretis secretorum_;[130] the _Summula_, ‘quam ego Archilaus transtuli de libro secretorum’;[131] and finally the _Mappa Archilei nobilis philosophi_.[132] The fact that these titles mention the _Secreta_ is enough to show us that in following up the alchemy of the Pseudo-Archelaus, we are on the right track. As we proceed the traces become still more interesting and significant. The _Summula_ offers the following curious passage: ‘Et hoc feci amore Dei et cuidam compatri meo, qui pauper sint [_sic_] et infortunatus, et postea fortunatus fortuna bona et amore Imperatoris Emanuelis et Frederici.’[133]