Great as Bacon was, he was far from being free from the mistakes and prejudices of those who went before him. Even some of the most wild and absurd o… - Joseph Priestley

In his Opus Majus he demonstrates, that if a transparent body, interposed between the eye and an object, be convex towards the eye, the object will appear magnified. This observation our author certainly had from Alhazen... this writer [Bacon] gives us figures, representing the progress of rays of light through his spherical segment, as well as endeavours to give reasons why objects are magnified... From the writings of Alhazen and these observations and experiments of Bacon together, it is not improbable that some monks gradually hit upon the construction of spectacles, to which Bacon's lesser segment, not withstanding his mistake concerning it, was a nearer approach than Alhazen's... Whoever they were that pursued the discoveries of Bacon, they probably observed, that a very small convex glass, when held at a greater distance from a book, would magnify the letters more than when it was placed close to them, in which position only Bacon seemed to have used it. In the next place, they might try whether two of these small segments of a sphere placed together, or a glass convex on both sides, would not magnify more than one of them. They would then find, that two of these glasses, one for each eye, would answer the purpose of reading better than one; and lastly they might find, that different degrees of convexity, suited different persons. It is certain that spectacles were well known in the 13th century, and not long before. ...It would certainly have been a great satisfaction to us to have been able to trace the actual steps in the progress of this most useful invention, without which most persons who have a taste for reading must have had the melancholy prospect of passing a very dull and joyless old age; and must have been deprived of the pleasure of entertaining themselves by conversing with the absent and the dead, when they were no longer capable of acting their part among the living. Telescopes and microscopes are to be numbered among the superfluities of life when compared to spectacles, which may now be ranked almost among the necessities of it; since the arts of reading and writing are almost universal.

The mind of man will never be able to contemplate the being, perfections, and providence of God without meeting with inexplicable difficulties. We may find sufficient reason for acquiescing in the darkness which involves these great subjects, but we must never expect to see them set in a perfectly clear light. But notwithstanding this, we may know enough of the divine being, and of his moral government, to make us much better and happier beings than we could be without such knowledge; and even the consideration of the insuperable difficulties referred to above is not without its use, as it tends to impress the mind with sentiments of reverence, humility, and submission.

It is the earnest wish of my heart, that your minds may be well established in the sound principles of religious knowledge, because I am fully persuaded, that nothing else can be a sufficient foundation of a virtuous and truly respectable conduct in life, or of good hope in death. A mind destitute of knowledge (and, comparatively speaking, no kind of knowledge, besides that of religion, deserves the name) is like a field on which no culture has been bestowed, which, the richer it is, the ranker weeds it will produce, If nothing good be sown in it, it will be dccupied by plants that are useless or noxious.