Jim, in a way i am glad that you are no expert in both artillery dynamics and photography ... for obvious reasons
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If you cared for the details narrated here on the effects of (solid shot) artillery, you wouldn't be surprised that a mid size cannon ball can penetrate a lamp post ... naturally a hollow one, as they all used to be. Neither would we be surprised that the post did not collapse because, being made of some sort of cast iron, would not bend.
Two reasons would explain the impressive quantity of holes in the post. Considering that the rioters had been equipped with nine cannons, after a few hours the number of volleys shot in the same direction would be fairly numerous, those shots on the post not being so implausible. Besides, this was an encounter between nationals; they would either avoid to aim at their keen with precision or, as untrained civilians, didn't have the ability to aim correctly at the target ... adding that the avenue where they were firing from (Liberdade) is rather inclined, a good reason to explain the high aiming.
One last reason to rely on the veracity of this photo is that, in a tiny country like Portugal, there is no Times magazine with their bucks or enough audience to justify a photographer to make up such a fantasy.
And by the way, i don't discern in the picture any background behind the crowd to check for collateral damage in the architecture.
To say that, the only unnatural fact i would admit, is that the (unknown) photographer invited those people to gather behind the post for an historic portrait.
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