Wooden board with pegs
Book III, Chapter 2, Paragraphs 25 to 50
In this experiment a wooden board is marked with lines showing its width and length and the two diagonals from corner to corner. A notch is engraved on one of the short sides to allow the observer to hold the board up to their eyes, with the width of the board equal to the eye seperaton. Objects are then placed at various positions on the board and the observer focuses their vision on each and the results are recorded.
The effects on display here are entirely a result of the positions of the two eyes and the fact that some objects will be closer to one eye etc. Therefore to see the effects two images are rendered in POV-Ray and then stacked ontop of each other to replicate what one might see with their eyes.
al-Haytham describes 6 different combinations of the pegs on the board to observe in paragraphs 28 to 33, click the buttons below the first two images to view the results from each.
Top view of the board with points marked as in Figure III.I in paragraph 26.
Side view of the board. Three coloured pegs may be placed on the surface of the board.
Click the button below to show the results from paragraph 28:
Click the button below to show the results from paragraph 31:
Click the button below to show the results from paragraph 32:
Click the button below to show the results from paragraph 33:
Copyright © Tom Bickley and Tom Lancaster, Durham University.