6

πλ
6

algabraic diagram presents to our observation the very identical object of mathematical research, that is, the form of the harmonic mean, which this equation aids one to study.
Not only is it true that by experimentation upon some diagram an experimental, or inductive, proof can be obtained of every necessary conclusion from a given premiss [I speak of premiss, in the singular, because two or more premisses can be reduced to a single correlative premiss, as is in fact done in my usual manipulation of logical algebra and other logical diagrams,] but what is more, no "necessary" conclusion is any more apodictic than inductive reasoning becomes, as soon as experiments may be multiplied, ad libitum, of no more cost than that of imagining a new diagram, and experimenting upon it in the imagination.
I might give a perfect

πλ
6