The entire last flag should have been below the horizon in the experiment you are talking about. Surely the only mistake he could have made was to lie the flag flat instead of vertically?
Something is not adding up, literally.
In SBR’s ENAG Experiment #2, he describes the set up as follows:
"Along the edge of the water, in the same canal, six flags were placed, one statute mile from each other, and so arranged that the top of each flag was 5 feet above the surface. Close to the last flag in the series a longer staff was fixed, bearing a flag 3 feet square, and the top of which was 8 feet above the surface of the water”
Observer seems to be at 5 feet based upon the diagrams.
He claims that the last flag, at 6 miles out, at 8 feet tall (The others 5 feet tall) should be, on RE: "but the top of the last and largest flag, being 3 feet higher than the smaller ones, would have been 13 feet 8 inches below the line of sight at the point B.” Meaning, 13 feet 8 inches below the 5 foot observer line of sight.
But, instead, according to Bilsin’s calculator, the top of the 8 foot flag at 6 miles out still has about a foot visible. Meaning the top of the 8 foot flag in SBR’s experiment would only be about 4 feet below the 5 foot line of sight.
Why is is SBR saying 13 feet 8 inches when it should only be 4 feet?
Bilson’s Calc: