I have often attempted the composition of such tables, but could not finish them through failure of means and the folly of those whom I had to employ." Books were difficult and sometimes even impossible to procure.

"The scientific works of Aristotle, of Avicenna, of Seneca, of Cicero, and other ancients cannot be had without great cost; their principal works have not been translated into Latin, and copies of others are not to be found in ordinary libraries or elsewhere.

The admirable books of Cicero de Republica are not to be found anywhere, so far as I can hear, though I have made anxious enquiry for them in different parts of the world, and by various messengers.

I could never find the works of Seneca, though I made diligent search for them during twenty years and more.

And so it is with many more most useful books connected with the science of morals." It is only words like these of his own that bring home to us the keen thirst for knowledge, the patience, the energy of Roger Bacon.