each tended to twist the rod horizontally in the same direction. The force required to produce the observed deflection was calculated from the time of swing of the rod and balls when left to themselves. The force exerted upon either ball by a known spherical mass of metal, with its centre at a known distance, being thus determined, it was easy to calculate what mass, having its centre at the centre of the earth, would be required to attract one of the balls with the force with which the earth was known to attract it. Dr. Wilson sums up Cavendish's view of life in these words:-- His theory of the universe seems to have been that it consisted _solely_ of a multitude of objects which could be weighed, numbered, and measured; and the vocation to which he considered himself called was to weigh, number, and measure as many of these objects as his allotted three score years and ten would permit. This conviction biased all his doings--alike his great scientific enterprises and the petty details of his daily life. [Greek: _Panta metro, kai arithmo, kai stathmo_], was his motto; and in the microcosm of his own nature he tried to reflect and repeat the subjection to inflexible rule and the necessitated harmony which are the appointed conditions of the macrocosm of God's universe. COUNT RUMFORD. Benjamin Thompson, like Franklin, was a native of Massachusetts, his ancestors for several generations having been yeomen in that province, and descendants of the first colonists of the Bay. In the diploma of arms granted him when he was knighted by George III., he is described as "son of Benjamin Thompson, late of the province of Massachusetts Bay, in New England, gent." He was born in the house of his grandfather, Ebenezer Thompson, at Woburn, Massachusetts, on March 26, 1753. His father died at the age of twenty-six, on November 7, 1754, leaving the infant Benjamin and his mother to the care of the grandparents. The widow married Josiah Pierce, junior, in March, 1756, and with her child, now a boy of three, went to live in a house but a short distance from her former residence.