Et hæc scientia certificat omnia naturalia et artificialia in particulari et in propria disciplina, per experientiam perfectam; non per argumenta, ut… - Roger Bacon

Oh how delightful is the taste of wisdom to those who are thus steeped in it from its very fount and origin. They who have not tried this cannot feel the delight of wisdom, just as a sick man cannot estimate the flavour of food. But because they are affected with this sort of mental sickness, and their intellect in this matter is as it were deaf from their very birth, so as not to appreciate the delight of harmony, on this account they grieve not at this so great loss of wisdom, though indeed without doubt it is an infinite loss.

For the things of this world cannot be made known without a knowledge of mathematics. For this is an assured fact in regard to celestial things, since two important sciences of mathematics treat of them, namely theoretical astrology and practical astrology. The first … gives us definite information as to the number of the heavens and of the stars, whose size can be comprehended by means of instruments, and the shapes of all and their magnitudes and distances from the earth, and the thicknesses and number, and greatness and smallness, … It likewise treats of the size and shape of the habitable earth … All this information is secured by means of instruments suitable for these purposes, and by tables and by canons .. For everything works through innate forces shown by lines, angles and figures.

Mix together saltpetre, luru vopo vir con utriet [powdered charcoal], and sulphur, and you will make thunder and lightning, if you know the method of mixing them.