X PREFACE. may be, perhaps, arranged in a different manner, as the fa6ts will always keep their value. It will contain likewife, an explanation of the belt ellablilhed me thods of making chemico-pharmaceuth cal preparations, with an advantage both for the operators, and for phyficians, who are to make ufe of them. Many medicines, or preparations, have loft their reputation, owing to the improper manner of preparing them. I have alfo noticed the methods of difcovering the adulterations of the different articles. The whole will be comprifed in one Volume. Before I conclude, I beg leave to mention a faft which I lately afcertained, and which relates to the experimental part of this Work, in making the che mical analyfis of minerals. It. is the method