Page:Petty 1647 Advice to Hartlib.djvu/25

 amongst men: He needeth not to describe every punctilio in making all the aforementioned particulars, and yet leave no more defects, then may be supplyed by every common understanding. For we question whether (if he should engage himselfe in such an endlesse labour) a man by the bare light and instruction of the Book could attaine to a dextrous practice of a trade, whereunto hath been required seven yeares Autopsia. But are confident that the help of this Book will lessen the former tæditum by more then half. He should not so abridge the Work as not to distinguish between Instruments of the same name, as between a Loome to weave Kersies, and another, wherein to weave silk Ribbands or Stockings.

He should all along give the Mechanicall reason of every Instrument Materiall and operation, when the same is sensible and cleere. He should all along note his own defects in setting down these Histories, in case he had not at the time of the writing thereof sufficient information, and withall the deficiencies of the Trades themselves.

Now whereas there be divers Wayes and Methods of working most Manufactures, he should in each thing stick close to the way of some one Mr. but note al the diversities he Knoweth, & give his Opinion of the use and goodnes of each.

Moreover the Oeconomy, Sive Ars augendas rei familiaris in all Professions ought to be enquired into. viz. What seasons of the yeare are most proper to each Worke, which the best places and times to buy Materials, and to put off the Commodities when finished, how most thriftily to hire, entertaine, and oversee servants and Workmen, how to dispose of every excrement and Refuse of Materials, or of broken, worne, or otherwise unserviceable Tooles and Utensils, with all Cauteles, Impostures and other sleights good or bad, whereby men use to over-reach one another.

There ought to be added to this work many and various indices besides the Alphabeticall ones, as namely one of all the Artificials mentioned in the whole worke.

Another of all the Naturall Materials or Elements of Artifials, by what Artificers used, from whence they come, Rh