Now this discourse which might otherwise have been omitted, was therefore appointed, that the cause of the germination of vegetables might be made the more manifest; and that what things have been spoken of the attraction, and fixation of all things might the better be understood. The germination therefore, and multiplication of both minerals, vegetables and animals must be spontaneous, and not forced, as is that barren and frustraneous of the false Chymists, because preternatural. Wherefore when you fix any thing be cautious in the adding of any thing that should retain it, with which nothing can be fixed. Fire indeed doth always do its office; but it knows not how to help any preternatural thing; which it doth wholly destroy, against which nothing can be prevalent, unless it be rightly ordained according to Nature. And thus much is spoken for instruction sake, to thee that intendest to fix any thing, lest otherwise thou losest thy labour. _Of the making of the best crucibles._ The best crucibles that are requisite for the fourth furnace, not being found in every place, I thought it worth while to set down the manner of making them: for I am not ignorant how oftentimes many for want of these are constrained to be content with those that are useless, and truly with great loss of metals, whilest the crucibles are broken in the fire, and consequently with a tediousness in drawing them out of the ashes. Chymists have been in a great errour a long time, and not only they but also goldsmiths, and they that separate metals, as also others that need the help of crucibles, who perswade themselves that the best earth that is fit to make the best crucibles is to be found no where but in _Hassia_; and therefore with great charges have caused that Gibsensian crucibles be brought over; not considering that almost in every place in Germany such earth is to be found, which indeed is a very great folly of men, proceeding from the not knowing of good earth which is to be found almost every where. I do not deny but that the earth of _Hassia_ is very good for crucibles, tyles, retorts, and other vessels which are to be set in a very great Fire, for which cause also is commended Gibsensian, and Waldburgensian crucibles.