The property of cords contracting their length by moisture became generally known, it is said, on the raising of the Egyptian obelisk in the square facing St. Peter's, at Rome, by order of Pope Sixtus V. The great work was undertaken in the year 1586, and the day for raising the obelisk was marked with great solemnity. High mass was celebrated at St. Peter's, and the architect and workmen received the benediction of the Pope. The blast of a trumpet was the given signal, when engines were set in motion by an incredible number of horses; but not until after fifty-two unsuccessful attempts had been made, was the huge block lifted from the earth. As the ropes which held it had somewhat stretched, the base of the obelisk could not reach the summit of the pedestal, when a man in the crowd cried out, "_Wet the ropes!_" This advice was followed, and the column, as of itself, gradually rose to the required height, and was placed upright on the pedestal prepared for it. ------------------ THE DEATH OF DR. BLACK. In the society of friends such as Adam Smith, Hume, Carlyle, Home, Hutton, Playfair, and Dugald Stewart, the closing days of this great and gentle chemist wore tranquilly away. Towards the end, he sank into a low state of health, and only preserved himself from the severe shocks of the weather in the changeable climate of Edinburgh, by a degree of care and abstemiousness rarely surpassed even by the devoutest Brahmin. "It was his generous and manly wish, that he might never live to be a burden to his friends; and never was the wish more completely gratified. On the 26th November 1799, in the seventy-first year of his age, he expired without any convulsion, shock, or stupor, to announce or retard the approach of death. Being at table with his usual fare--some bread, a few prunes, and a measured quantity of milk diluted with water; and having the cup in his hand when the last stroke of the pulse was to be given, he had set it down upon his knees, which were joined together, and kept it steady with his hand in the manner of a person perfectly at ease; and in this attitude expired, without spilling a drop, and without a writhe in his countenance; as if an experiment had been required, to show to his friends the facility with which he departed. His servant opened the door to tell him that some one had left his name; but getting no answer, stepped about half way towards him, and, seeing him sitting in that easy posture, supporting his basin of milk with one hand, he thought that he had dropped asleep, which he had sometimes seen happen after his meals. The man went back and shut the door; but before he got down stairs, some anxiety that he could not account for made him return, and look again at his master. Even then, he was satisfied, after coming pretty near, and turned to go away; but again returned, and coming quite close, found his master without life."