A B *c* D E F A B *c* D *e* F A *b* C D *e* *f* A *b* *c* D E *f* A *b* *c* D *e* *f* A *b* *c* *d* E F A *b* *c* *d* *e* F *a* B *c* D E F *a* B *c* D *e* F *a* B *c* *d* E F *a* *b* C D E F *a* *b* C D *e* F *a* *b* C D *e* *f* *a* *b* *c* D *e* *f* *a* *b* *c* D E *f* *a* *b* *c* *d* *e* F
PROBLEM IX.
From The Principles of Science: A Treatise on Logic and Scientific Method by William Stanley Jevons.