As it does not appear probable that the tubes are produced by successive distinct shocks, we must believe that the lightning, shortly before entering the ground, divides itself into separate branches.
The neighbourhood of the Rio Plata seems peculiarly subject to electric phenomena.

In the year 1793, one of the most destructive thunderstorms perhaps on record happened at Buenos Ayres: thirty-seven places within the city were struck by lightning, and nineteen people killed.

(3/12.

Azara's "Voyage" volume 1 page 36.) From facts stated in several books of travels, I am inclined to suspect that thunderstorms are very common near the mouths of great rivers.

Is it not possible that the mixture of large bodies of fresh and salt water may disturb the electrical equilibrium?
Even during our occasional visits to this part of South America, we heard of a ship, two churches, and a house having been struck.