the historians of science have only recently learned of the existence of a sixth volume of the grandly conceived work of the abbé raffaello caverni entitled storia del metodo sperimentale in italia. five volumes had already been published between 1891 and 1898. the sixth volume was published, one might say, in an almost furtive way. in fact, the first notice of it was given in a journal by aldo mieli just a few months ago. among materials he is collecting under the heading, “for a biography of the italian historians of science,” in addition to other things already said about caverni in a previous issue, mieli has published the following “information received from g. vacca”: “the printing of the sixth volume of the history of the experimental method in italy dealing with the history of hydraulics had been started but was interrupted by the author's death. about 450 pages have been printed, the greater part of the copies of the loose sheets have been lost.”