With the opinion expressed at our last meeting by Mr. J. W.JAFFRAY, in his very valuable contribution to the literature of gold Extracting Machinery, that the subject is a very extensive one, I can here record my very cordial agreement; and in submitting the following notes on the results of my own experience, I hope to serve Mr. JAFFRAY'S purpose of promoting further discussion on a subject that deserves the serious consideration of every practical mining manager. I propose to deal with the subject purely from an economic point of view, and to advocate the use of the article that my own experience has convinced me to he the best suited for the particular work has to perform. Considering the almost numberless varieties of gold-saving machines now in use, I do not for a moment expect all my opinions to receive unqualified approval; and if the expression of them will but help to elicit from other millmen the results of their experiences, I will be satisfied that my humble effort has been of some material value.