_I desire the Lovers of =Chymistry= to accept my Labours, with the same good will that I have undergone them, having no other end but to serve my Country. And I hereby return thanks to all those generous spirited Gentlemen and others, who have Subscribed to, and promoted this Work, without whose assistance (the Charge being very great, as well as the labour (to me) almost insupportable) it must yet have remained hid and unserviceable to the =English= Reader. But I am in an especial manner obliged to that publick spirited Gentleman (whom I ought to name, were it lawful to do it without his leave) who freely offered me and put into my hands a not inconsiderable part of the Materials for this Work, which part also had been more considerable than it was, had not the Spirit of some, (who unjustly hinder’d it) been as Mean and Sordid, as his was Generous. But that Loss was, in part, made up to me, by a well-minded Artist, to whom I also return Thanks._ _I have Printed this Book upon far better and larger Paper than I proposed to do it in; for at the time of setting forth my first Proposals, I had not the =German= Pieces, but when they came to my hands, upon a more accurate computation of the matter, I found that if I should go on to do the Work upon the Paper I had proposed, the Book would swell to too great a thickness for its breadth and length, and not be only ill shaped, but inconvenient to be read. By this means my Subscribers have a much better Book than I promised them, although the Charge hath also been Considerably greater to me, than I at first expected._