With the death of Lord Kelvin on the 17th of December, in the 84th year of his life, there was ended a career full of usefulness to mankind. To wonderful scientific attainments he united a faculty of practical achievement that placed him in the first rank of those who were pushing back the boundaries of the unknown. In his work the creative imagination played a remarkable part, but ever ruled and guided by rare mathematical perception and insight. Although his discoveries were perhaps not so sensational or so startling to the layman, they were fraught with a scientific worth that only his colleagues could fully appreciate. His work often blazed the trail, making the way for those who were to follow, as well as providing them with the means of pressing on to a more distant goal than was ever before reached. Nor did he lack the companionable qualities that are so falsely thought to be destroyed by a too close devotion to science, but kept up his interest in happenings outside of his chosen sphere. No better summing up of his life can be given than that of Thomas A. Edison, a friend of thirty-five years' standing: "Lord Kelvin certainly had the master mind in science, for the world seldom sees such a man as he was. First of all he was great as a mathematician, and then he developed into the greatest of scientists. He was also of a practical turn, and the application he made of his researches enabled the human race to make rapid strides. I think it is safe to say that he gave more attention to such subjects as the power of the tides and the properties of the crust of the earth than any other scientist. "With his great ability as a mathematician, he compiled the results of his numerous experiments and gave to us many of the fundamental laws of science, which we are putting to practical test in our everyday lives." William Thomson, first Baron Kelvin, was born in Belfast on the 26th of June, 1824. His father, James Thomson, was professor of mathematics at Glasgow University, from which seat of learning he held the degree of LL.D. The younger Thomson always had taste for science, in fact, his scientific education commenced at the age of ten, for in 1834 he was a matriculated student of the University in which his father was professor. From Glasgow he went to St. Peter's College, Cambridge, better known as "Peterhouse," where he was graduated in 1845 as Second Wrangler; he was also first "Smith's Prizeman." In 1846 he was made a fellow of St. Peters and professor of natural philosophy at Glasgow, serving in the first capacity until 1852, and in the second for a space of over fifty years. He was again made a fellow of St. Peters in 1872. During the period of the laying of the various transoceanic cables, Thomson was called upon to lend his assistance, enjoying, as he did, even at that time, the reputation of England's greatest electrician. From 1857 to 1858, and from 1865 to 1866, he acted as electrician of the Atlantic cables, inventing in this capacity the mirror galvanometer and the siphon recorder. His achievements in connection with the Atlantic cable gave him a worldwide reputation, so that many other cable services next claimed his attention, notably the French Atlantic in 1869, the Brazilian and River Plate in 1873, the West Indian in 1875, and the Mackay-Bennett Atlantic in 1879. When the utilization of the water power of Niagara for manufacturing purposes was first discussed, Sir William Thomson was made chairman of the advisory board that had the matter in charge. His views on this subject, while in more or less direct opposition to American public opinion, are quite characteristic of the man. In 1902, at a reception at Columbia University, he spoke as follows: "Beautiful as is that wonderful work of nature, it would be more beautiful still if those waters fell upon turbine wheels, every one of which was turning the wheels of industry." Five visits in all were made to America by the scientist, two of a purely professional nature, connected with the laying of the cables, in 1865 and 1866, and three othersin 1884, in which year he delivered the Baltimore Lectures at Johns Hopkins, in 1897 and in . 1902. During the last trip, he visited a number of our universities, fronx several of which he received degrees, among them that of LL.D. from Yale. The honors showered upon Lord Kelvin bear witness to the appreciation of his work. In 1866, on the successful completion of the Atlantic cable, he was knighted by Queen Victoria, and received the freedom of the city of Glasgow. In 1892 he was made a baron, because of his services to mankind, although it is rumored that the nature of his politics may have assisted in the matter. In the year 1896, a jubilee was held in honor of his having occupied the chair of natural philosophy at Glasgow University for fifty years. Upon this occasion, the universities of Dublin, Cambridge, and Edinburgh each conferred upon him the degree of LL.D., while Oxford made him a D.C.L. He was a fellow of both the London and the Edin- burgh Royal Societies, receiving from the former the Royal medal, and from the latter the Keith prize. At one time or another he held the presidency of nearly every important learned society in England; of the mathematical and physical section of the British Association he has been the head five times. From abroad he received a great number of decorations. He was a grand officer of the Legion of Honor, a commander of the Order of Leopold, and a possessor of the Prussian Order pour le Mrite, and of the Order of the First Class of the Sacred Treasure of Japan. In December of the year 1877, he was elected foreign associate by the Paris Academy of Sciences. He was also a foreign member of the Berlin Academy of Science. The scientific achievements of this remarkable man are largely in the nature of inventions; in them mechanical complexity is noticeably absent, owing to remarkable grasp of the underlying theoretical principles. As has been mentioned above, he invented the reflecting galvanometer and the siphon recorder, neither of which, it is interesting to note, he wished to patent, desiring to give them to the world as a physician gives his discoveries. Others of his inventions are the compensated mariner's compass now generally in use, a tide gage, a tidal harmonic analyzer, and a tide pre-dicter. He also simplified Sumner's method of determining the position of a ship at sea. A very well-known apparatus of the greatest usefulness devised by him is the deep-sea sounder. By its use soundings can be made in one hundred fathoms of water by a steamer traveling at a speed of sixteen knots. Its essential parts are a piano wire and a detachable weight. His greatest work was done in the realm of electrical measurement, and there is practically no electrical quantity in existence for which he did not produce the necessary measuring device. Lord Kelvin's written works are in seven volumes, not including a "Treatise on Natural Philosophy," written in conjunction with Prof. P. C. Tait. Of these volumes, one consists of "Electrostatics and Magnetism," three of "Mathematical and Physical Papers," and three of "Popular Lectures and Addresses." His theoretical work is largely found in the monographs of the "Papers" for general physics, and in the "Electrostatics" for electricity. Army Dirigible Airships. We are gratified to note that Brigadier-General James Allen, chief signal officer of the United States Army, has issued specifications for the construction and supply of dirigible balloons for use of the army. It is the expectation, after experiments with this class of air vessels have proven their utility and value for signaling and other purposes, that the War Department will issue other specifications for the construction of aeroplanes and other heavier-than-air machines, capable of traveling through the air at a greater speed. The balloon specifications will be found in detail in the current SUPPLEMENT. Briefly, they provide for a gas bag not more than 120 feet in length, made of aluminium-coated silk, and containing two ballonettes, suitable valves, rip cord, etc., and a suspended body framework that can be easily taken apart". The balloon must be able to carry two men weighing 175 pounds each, plus 100 pounds of ballast. Suitable power must be installed to maintain a speed of twenty miles an hour in still air. The balloons are to be delivered at Fort Meyer, Va., where the trial tests are to be made. Applications should be sent to the Signal Office of the U. S. A., Washington, D. C, prior to January 15, 1908. Scale drawings of the proposed airship and a description of the engine to be used, as well as a certified check for 15 per cent of the price asked, must be submitted by every bidder. Living Flali on Board Ocean Steamers. An interesting departure has been recently made on the "Amerika" of the Hamburg-American Line by taking on board a special tank for keeping about a ton of living river fish for table use. It was an interesting question whether or not the fish would stand the fatigue of the sea voyage. A large tank of 5.85 cubic yards capacity (14.76 feet in length, 3.28 in width, and 3.28 in height) had been constructed on the boat deck of the steamer. This tank, which is of iron, and divided into two compartments, was protected against the escape of the water in case of heavy oscillations by roofing, as well as by perforated sheet-metal partitions similar to bulkheads The two main compartments of the tank are intended, one for housing trout, and the other for larger fish. As this experiment has been entirely successful, ocean steamers will in future be able to carry fresh fish instead of the fish preserved on ice, as much as two tons being readily stored in tanks of the kind described.