In the Rosenkreutz Database there is described how an old Greek Philosopher found a way to test it. Do a search for the term Flat Earth here - have a look at his results.
"A "flat-Earth" map drawn by Orlando Ferguson in 1893.
The main text reads:
MAP OF THE
SQUARE AND STATIONARY EARTH.
BY PROF. ORLANDO FERGUSON,
HOT SPRINGS, SOUTH DAKOTA.
Four Hundred Passages in the Bible that Condemn the Globe Theory, or the Flying Earth, and None Sustain It.
This Map is the Bible Map of the World.
Copyright by Orlando Ferguson, 1893.
The four corner angels each have the note:
Four Angels standing on the Four Corners of the Earth—Rev. 7: 1.
The Orlando Ferguson medallion note reads
PROF. ORLANDO FERGUSON,
HOT SPRINGS, S. DAKOTA.
The Globe Earth medallion note reads
These men are flying on the globe at a rate of 65,000 miles per hour
around the sun, and 1,042 miles per hour around the center of the earth
(in their minds). Think of that speed!
The footnote on the left reads:
SCRIPTURE THAT CONDEMNS THE GLOBE THEORY
And his hands were steady until the going down of the sun—Ex. 17:
12.
And the sun stood still, and the moon stayed.—Joshua 10: 12–13.
The
world also shall be stable that it not be moved.—Chron. 16: 30.
To him
that stretched out the earth, and made great lights (not worlds).—Ps.
136: 6–7.
The sun shall be darkened in his going forth.—Isaiah 12: 10.
The four corners of the Earth.—Isaiah 11: 12. T
he whole earth is at
rest.—Isaiah 14: 7.
The prophecy concerning the globe theory.—Isaiah:
29th chapter. Woe to the rebellious children, sayeth the Lord, that take
counsel, but not of me.—Isaiah 30: 1.
So the sun returned ten
degrees.—Isaiah 38: 8–9.
It is he that sitteth upon the circle of the
earth.—Isaiah 40: 22.
He that spreads forth the earth.—Isaiah 52: 5.
That spreadeth abroad the earth by myself.—Isaiah 54: 24.
My hand also
hath laid the foundation of the earth.—Isaiah 58: 13.
Thus sayeth the
Lord, which giveth the sun for a light by day, and the moon and stars
for a light by night (not worlds).—Jer. 31: 35–36.
The sun shall be
turned into darkness, and the moon into blood.—Acts 2: 20.
The footnote on the right reads:
Send 25 cents to the Author, Prof. Orlando Ferguson, for a book
explaining this Square and Stationary Earth. It Knocks the Globe Theory
Clean Out. It will Teach You How to Foretell Eclipses. It is Worth Its
Weight in Gold."