If you look at the complete verse, you'll notice that it says "Then soon with the emblem of truth overflowing, and dripping with coolness, it rose from the well"
Words like "overflowing and "dripping with coolness" point to the emblem of truth being water that rises from the well.
Technically it is true that Frederick Scott Archer introduced the concept of combining artificial and natural light in the studio, but it should be noted that this concept had been used before, just without much fame.
