Description.--A A A is a ring of thin wood; B B B, several spokes, movable round the fixed points C C C, and only allowed to move one way by the construction of the openings D D D; E E E, heavy weights fixed to the ends of the spokes. From the position in which the wheel is at present, it is evident that the weights on the right-hand side (1 and 2) acting at a greater distance from the center than those (4 and 5) on the other side, will cause that side to descend until the spoke 1 reaches the position 3, when it will exert no moving influence, but by which time the weight 8 will have fallen into the position 1, when a similar effect will take place, and so on with the rest. Leonardo da Vinci It is with a mingled feeling of sorrow and exaltation that we note the Perpetual Motion labors of the great Leonardo da Vinci. Of all of the men who ever gave the subject more than a passing notice he is the most famous. Leonardo da Vinci was an Italian, born in 1452, and died in 1519. He was the illegitimate son of Florentine, lawyer. His mother has been variously described as a peasant, and as of gentle birth. Little about her is known. The father belonged to a family of lawyers, and never repudiated the son, but took him, educated him, and cared for him. It is well for the world that he did, for Leonardo da Vinci has perhaps contributed more to art and learning in the world than any other single individual that ever lived. He was a painter, a sculptor, an architect, a musician, a mechanician, engineer and natural philosopher. Each subject in art or science that he touched he not only mastered, but improved and embellished. He painted the original of the well-known picture of the Christ and His twelve Apostles, known as the "Last Supper," or the "Last Supper of Our Lord." This, and Mona Lisa, are perhaps the paintings by which he is known to the greatest number of people, and are considered by many connoisseurs the highest perfection in art ever attained by mortal man. But, as painter and sculptor, he is to be regarded as among the greatest, if not the very greatest that ever lived. In art he ranks beside, if not ahead of Michelangelo and Raffael, and yet they are known only as artists, while he was preeminent in both art and science. The work he did in natural science was entirely original and emanated from an inherent initiative and originality, and as a scientist, he is entitled to rank below only Newton, Gallileo and Copernicus, and very few others. In all the history of the world he is the only man of whom it can be said that he attained the apex of eminence in both art and science. The information concerning Leonardo da Vinci's devices for obtaining Perpetual Motion is extremely meager. There does not seem to be extant any detailed explanation of just how he expected his different designs to work. All that is known concerning his efforts is sufficiently illustrated by the following cuts and language from Dircks: