reasoning, and the conclusions to which it had led him, to Boulton, in a letter written in December, 1782, and addressed a letter some time afterward to Priestley, which was to have been read before the Royal Society in April, 1783. The letter was not read, however, until a year later, and, three months after, a paper by Cavendish, making the same announcement, had been laid before the Society. Watt stated that both Cavendish and Lavoisier, to whom also the discovery is ascribed, received the idea from him. The action of chlorine in bleaching organic coloring-matters, by (as since shown) decomposing them and combining with their hydrogen, was made known to Watt by M. Berthollet, the distinguished French chemist, and the former immediately introduced its use into Great Britain, by inducing his father-in-law, Mr. Macgregor, to make a trial of it. The copartnership of Boulton & Watt terminated by limitation, and with the expiration of the patents under which they had been working, in the first year of the present century; and both partners, now old and feeble, withdrew from active business, leaving their sons to renew the agreement and to carry on the business under the same firm-style. Boulton, however, still interested himself in some branches of manufacture, especially in his mint, where he had coined many years and for several nations. Watt retired, a little later, to Heathfield, where he passed the remainder of his life in peaceful enjoyment of the society of his friends, in studies of all current matters of interest in science, as well as in engineering. One by one his old friends died--Black in 1799, Priestley, an exile to America, in 1803, and Robison a little later. Boulton died, at the age of eighty-one, August 17, 1809, and even the loss of this nearest and dearest of his friends outside the family was a less severe blow than that of his son Gregory, who died in 1804. Yet the great engineer and inventor was not depressed by the loneliness which was gradually coming upon him. He wrote: "I know that all men must die, and I submit to the decrees of Nature, I hope, with due reverence to the Disposer of events;" and neglected no opportunity to secure amusement or instruction, and kept body and mind constantly occupied. He still attended the weekly meetings of the club, meeting Rennie and Telford, and other distinguished men of his own and the succeeding generation. He lost nothing of his fondness for invention, and spent many months in devising a machine for copying statuary, which he had not perfected to his own satisfaction at the time of his death, ten years later. This machine was a kind of pentagraph, which could be worked in any plane, and in which the marking-pencil gave place to a cutting-tool. The tracing-point followed the surface of the pattern, while the cutting-point, following its motion precisely, formed a fac-simile in the material operated upon.