Three Dots between paragraghs

Could anyone explain why there are occasionaly three dots between two paragraphs, though not every two, in a chapter in a book? Thanks!

(The dots are in the middle.)

but the architectural project was abandoned, and the library of over six thousand volumes, annotated by Voltaire page by page in the margins, was placed in a hall of the Hermitage in St. Petersburg. In the center of this space, the place of honor, was an exact copy of Houdon’s remarkable statue of Voltaire seated. It is there today.

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Voltaire was interested in Russia. In 1757, he had persuaded Empress Elizabeth to commission him to write a history of Russia under her father, Peter the Great. The first volume had been published in 1760; he was still