27 Aug. 1814

Logic

Ch. │ │ Invention

'.2 Helps to all

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Memento 8. In such your survey of existing inventions, look out in preference for the latest of all, not looking backwards but for some special reason - Postrema exquirito.

Memento 9. Instruction - Quodlibet cum quolibet. To every thing forget not to apply any thing. Suppose an indefinite multitude of objects, which in consideration of certain properties or qualities, in respect of which they are found or supposed to agree, and certain others, in respect of which they have been found or supposed to disagree - having been all of them placed in one or other of two classes, some article belonging to the one class has with success, i.e. with some new effect which either has been found to be or affords a prospect of being found to be advantageous, been applied - no matter in what manner nor to what purpose in particular, to some article belonging to the other class: in like manner, frame a general resolution not to be departed from in any instance but for some particular cause to apply to each article belonging to the one class every article belonging to the other.

The sort of special cause here in question will be one of these two: viz. 1. Apparently preponderant probability of producing any new result at all. 2. Apparently preponderant probability that the new result if any will instead of proving preponderantly advantageous prove preponderantly disadvantageous.

N.B. Among physical arts and sciences, the branch of art and science to which this rule or memento is in a peculiar degree applicable, is the Chemical including in so far as they belong to it the several subordinate and practical and subordinate branches of art and science which come under its department: ex. gr. cookery, pharmacy, agriculture, architecture in so far as concerns materials.

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