the letters do matter, you need guidance of which ones to use

i found a different year than 1804

not my favorite puzzle in the book. the earlier clue about refraction ultimately led me to reversing the sequence of numbers at the top and reversing the direction of the "pipes" below as well.

look at the top horizontal black portion of the image and focus on all the white parts within the black

there are two colors of letters on page 113 and two colors of hands on page 109

the image three posts above has all you need

i understand that a glass of water will refract light and distort objects, but how do i apply that here?