Among the minor, but very useful inventions, are _water scoops_ for picking up water for a train while in motion, consisting of a curved open pipe on a car, the mouth of which strikes a current of water in an open trough between the tracks and picks up and deposits in a minute a car load of water for the engine. _Nozzles_ to emit jets of great velocity, and ball nozzles terminating in a cup in which a ball is loosely seated, and which has the effect, as it is lifted by the jet, to spread it into an umbrella-shaped spray, are of great value at fires in quenching flame and smoke. Next to pure air to breathe we need pure water to drink, and modern discoveries and inventions have done and are doing much to help us to both. Pasteur and others have discovered and explained the germ theory of disease and to what extent it is due to impure water. Inventors have produced _filters_, and there is a large class of that character which render the water pure as it enters the dwelling, and fit for all domestic purposes. A specimen of the latter class is one which is attached to the main service pipe as it enters from the street. The water is first led into a cylinder stored with coarse filtering material which clears the water of mud, sediment and coarser impurities, and then is conducted into a second cylinder provided with a mass of fine grained or powdered charcoal, or some other material which has the quality of not only arresting all remaining injurious ingredients, but destroys organisms, neutralises ammonia and other deleterious matter. From thence the water is returned to the service pipe and distributed through the house. The filter may be thoroughly cleansed by reversing the movement of the water, and carrying it off through a drain pipe until it runs clear and sweet, whereupon the water is turned in its normal course through the filter and house. In a very recent report of General J. M. Wilson, Chief of Engineers, U.S.A., the subject of filtration of water, and especially of public water supplies in England, the United States, and on the Continent, is very thoroughly treated, and the conclusion arrived at there is that the system termed “the American,” or mechanical system, is the most successful one. This consists, first, in leading the water into one or more reservoirs, then coagulating suspended matter in the water by the use of the sulphate of alumina, and then allowing the water to flow through a body of coarse sand, by which the coagulated aluminated matter is caught and held in the interstices of the sand, and the bacteria arrested. All objectionable matter is thus arrested by the surface portion of the sand body, which portion is from time to time scraped off, and the whole sand mass occasionally washed out by upward currents of water forced through the same. By this system great rapidity of filtration is obtained, the rate being 120,000,000 gallons a day per acre.