Some judge books by their thickness, as though they had been written to exercise the arms, instead of the mind.

[Estiman algunos los libros por la corpulencia, como si se escriviessen para exercitar antes los braços que los ingenios.]

Baltasar Gracián y Morales (1601-1658) Spanish Jesuit priest, writer, philosopher

The Art of Worldly Wisdom [Oráculo Manual y Arte de Prudencia], § 27 (1647) [tr. Fischer (1937)]
    (Source)

(Source (Spanish)). Alternate translations:

Some value Books for their bulk, as if they were made rather to load the Arms than to exercise the mind.
[Flesher ed. (1685)]

Some reckon books by the thickness, as if they were written to try the brawn more than the brain.
[tr. Jacobs (1892)]

Some praise books for their girth, as if they were written to exercise our arms, not our wits.
[tr. Maurer (1992)]