A use for white mice is mentioned in a paper read before the Chemical, Metallurgical, and Mining Society of South Africa by Messrs. Macaulay and Irvine, who suggest that the law should provide that a supply of white mice should be kept at all collieries. It is well known that these animals are peculiarly susceptible to poisoning by CO (carbon monoxide), their susceptibility being so great that they can be employed as a reliable test for dangerous quantities of the gas. The respirating exchange in a mouse is twenty times as rapid as in a man, and consequently the mouse exhibits symptoms of blood saturation much more rapidly. Dr. Haldane proved that with 0.4 per cent CO in the air, a mouse gave symptoms of illness - a staggering gait - in 1 1/2 minutes, and that it becomes roticious in three minutes, whereas lie himself did not feel discomfort for half an hour. This gives a sufficient interval to allow a miner to escape. Dr. Haldei e says that air must be regarded as dangerous the moment the test mouse becomes incapable of motion. The law should therefore provide that whenever there is a suspicion of an accumulation of CO in collieries or metalliferous mines these animals should be used as a test.

The Quebec cantilever bridge, now being built over the St. Lawrence River, is to beat all the bridges in the world in having a single span of 1800 ft. The Williamsburg suspension bridge over the East River has a span of 1600 ft., only 5 ft. greater than that of the Brooklyn bridge; and asidefrom suspension bridges, of which these are the greatest, there is the Forth railway bridge, with two spans of 1710 ft. each. This new bridge at Quebec is the only one over the St. Lawrence River below Monreal, 130 nautical miles distant.

To draw a fine gold wire, the gold may be enclosed a covering of copper, and the whole drawn down to the finest mechanical limit; then the copper layer is dissolved off, leaving the fine gold nucleus.

Speaking of industrial education in the United States, Heinrich Back, of the industrial school at Frankfort-on-the-Main, Germany, expresses surprise that our government has taken no steps towards providing systematic training of its citizens in industrial lines. This is at present entirely in the hands of philanthropic individuals, and no schools intended for teaching trades have been established by government effort. In the larger cities, good schools such as the Drexel Institute of Philadelphia, Pratt Institute in Brooklyn, and Lewis Institute in Chicago, have been established, but there are large sections where it is impossible for boys to obtain any industrial training. This is in direct contrast to the policy of the German government, which maintains in every part of the empire good trade, industrial and technical schools.

The proper site for a windmill, where there is no danger of its being blown over, has been generally supposed to be a place sheltered by trees or barns. Actually, however, the safest place is on a hill, where the wind can strike it equally from all directions. In such a location shifting winds are less pronounced than behind buildings or hills, and it is also found that there is less lifting force to the wind in the open than behind structures.

A new development in electric welding is the automatic production of continuous rolls of wire fencing, says the "Iron Age. " A number of galvanized wires are fed from reels arranged vertically and parallel to each other, and from another reel placed transversely to these are cut off lengths of wire, which are fed horizontally across the vertical wires. Where the horizontal and vertical wires intersect, these are welded together by means of small transformers. The welded section then moves forward a predetermined distance, and the operation is repeated.