IT is not intended in this paper to deal with the reduction and the dressing of ores generally; it will be restricted to the methods practised on several of the goldfields of Victoria, but especially to the systematical treatment of "slimes," with the expectation that thereby less gold will be lost in them than has been the case hitherto. With this aim in view it was essential as a preliminary, to ascertain the actual loss of gold, as carried away in the "waste tailings" of some of the principal crushing establishments in this colony. To do so satisfactorily, evidently the first step, and the one on which would depend the true value of the results obtained by the inquiry, was to collect, in each case, exact and fair average samples of the ultimate " waste tailings " from each crushing plant.