The great difficulty, especially in hot climates like that of India, which besets the movements of British troops in a campaign, whether on the march or in camp, is that of getting a pure supply of drinking water. The invention of the Patent American Tube Wells, which proved so useful to our army in Abyssinia, is one great step towards securing this object in future. A second, which seems likely to be of great value, is the adoption of travelling filters. We give an Illustration of the Army Filter-Van constructed by Messrs. E. H. Bayley and Co., of the Steam Wheel Works, Newington causeway. This filter-van, which is specially designed for our army in India, holds 250 gallons of unfiltered water in a tank, inclosed in a wood casing, by which the water is kept cool in the hottest weather. The water is drawn in through suction-hose screwed on. A well-cistern is attached beneath the tank, through which the water passes to the filters. At the bottom of the well is a sediment-trap, in which mechanical impurities settle, and whence they are drawn off by a cock at the bottom; in the same way, also, impurities are collected and drawn off from the filters. The filters are composed of a layer of sand, a body of charcoal, and another layer of sand. They are cleaned by attaching an air-pump to the sediment-cocks, and sending a stream of atmospheric air through them. The water passes to the filters through sponges, and thence upward through the filtering material, flowing over into a receiver, from which it is drawn off pure by cocks at the tail of the van. The tanks and filters can be examined through manholes. By employing the ascension principle of filtration, a much better result is believed to be obtained than by the downward system. Each of the two receivers will hold 25 gallons, which ensures a constant supply of 50 gallons of pure water. If the water be very bad it can be passed from one filter to another. The filters are also so arranged that they can be used singly or together. The military authorities are investigating the merits of Bayleys' filter-van; and, by desire of the Commander-in-Chief, two of the vans were brought to the Horse Guards for his inspection. His Royal Highness, who feels a kind interest in the comfort of the soldier, examined and tested the invention, and expressed to Mr. Bayley his full approbation of it. It has been said that during the Italian campaign more French soldiers died from want of water than fell in battle. It is well, therefore, for our Government to provide the commissariat department with the best appliances for ensuring an abundant supply of pure water. Any negligence in this respect is not only cruel to the men, but injurious to the interests of the country. Notwithstanding the precautions that are taken, cholera and other epidemics are brought on amongst our men at India by the bad water they are obliged to drink, and for every death that ensues this country suffers a direct pecuniary loss of the sum expended upon the soldier's training, outfit, and transport. There is now sitting a Commissariat Committee, which has hitherto not been over prompt in studying the sanitary requirements of our Indian army, and it is high time for this great and crying evil to be remedied. The peculiar merits of Messrs. Bayley's filter-van are the ease with which it can be filled, as shown in the Illustration; the manner in which the water is kept cool in the van, and subjected to a thorough filtration before being drawn off by the taps at the back; and, lastly, the method by which the large filters can be easily cleansed without removal from the van.
Source: The Illustrated London News, Vol. LIV, Jan. 9, 1869, p.45