The Roman History · Amm. 22.15.29

And their shape received this name from the geometricians because they rise in a cone like fire (πῦρ). And huge as they are, as they taper off gradually, they throw no shadow, in accordance with a principle of mechanics.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
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