Sentences of a paragraph are given below in jumbled order. Arrange the sentences in the correct order to form a meaningful and coherent paragraph.

A. He repeated the experiment, increasing the amount until he had weighed up to a thousand pounds.

B. During the spring of 1717, the iron foundries in a remote district were often visited by a thin, middle-aged man with a notebook.

C. Three cauldrons were next prepared under his directions.

D. He would weigh out two pounds of iron, have them heated till they were red-hot and then weigh them again.

To arrange the sentences in a logical and coherent paragraph, let us analyze the context and chronological order of events described in the sentences:

1. Sentence B introduces the main character ("a thin, middle-aged man with a notebook") and the setting ("During the spring of 1717, the iron foundries in a remote district were often visited..."). This is the most logical opening sentence as it establishes the background and introduces the subject.
2. Sentence D explains what the man would do during these visits: "He would weigh out two pounds of iron, have them heated till they were red-hot and then weigh them again." This describes his initial experiment.
3. Sentence A builds directly on Sentence D by showing the progression of this experiment: "He repeated the experiment, increasing the amount until he had weighed up to a thousand pounds." The transition from weighing two pounds (in D) to repeating the experiment with larger amounts up to a thousand pounds (in A) is logically seamless.
4. Sentence C describes the next stage of his activities: "Three cauldrons were next prepared under his directions." The word "next" signals that this step follows the completed weighing experiments described in D and A.

Therefore, the logical sequence of the sentences is B-D-A-C.

The correct option is BDAC.