I have stumbled upon the following alleged Newton's quotes, but I could not find them in any of their works.
No great discovery was ever made without a bold guess.
No sciences are better attested than the religion of the Bible.
What we know is a drop, what we don't know is an ocean.
I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.
Where exactly do they come from? Are they apocryphal? Is there anywhere a comprehensive compilation of alleged Newton quotes indicating their authenticity and source?