Fig. 3 illustrates a modified form of the apparatus of compact construction, which is more economical than that shown in Fig. 1 and occupies much less space. In this arrangement, it will be observed, there is only one filtering compartment (A), which, however, is quite sufficient for all practical purposes. The compartment (D) is filled with a layer of wool which is held in place by a wire-gauze cover, which arrests the floating particles of organic matter. Fig. 4 shows an arrangement for a country privy or for privies where there is no regular supply of water. Before using the apparatus the receptacle or "holder" (E), the compartment (B) and the bowl (F), which is of peculiar construction and separated from (B) by a partition, are all filled with pure water. Occasionally or daily a bucket of clean water may be cast into the bowl. A strainer or perforated plate extends across the compartment (B) from the partition to the filter in rear of the privy. (A) represents the filtering or overflow compartment, showing the layers of filtering material. This arrangement can be made double, as shown in (Fig 5), with only one "holder" and one filtering compartment for the two sides. WATER SUPPLIES. THE QUESTION OF POTABLE WATER. The question of good drinking water is one of the first and most important to all communities; for water, next to atmospheric air, is the first necessity of living beings. It is for this reason that aggregations of population are generally found near rivers or rivulets, which serve a double purpose. They supply the populations grouped upon them with water, and are utilized to carry away the filth; but when the populations increase the latter condition can no longer be fulfilled without detriment. It is a well recognized fact that the germs of infectious diseases are disseminated through the medium of water, and especially is this the case with reference to the germs of typhoid fever and cholera. These diseases have been known to pass from one community to another with a rapidity proportionate to the flow of the current of river or stream on which the towns are located. In a report made to the Academy of Medicine of Paris by M. Marey, in October, 1884, after the outbreak of cholera in France, a number of cases are cited to illustrate the rapidity and certainty with which the disease is communicated from village to village by water courses. But it is not only the small towns which are exposed to the reception of disease in this manner; large cities are also subject to the same prejudicial influence. In this manner cholera was carried to Genoa, Italy, during the epidemic of 1884. A week before the malady made its appearance in that city it prevailed at Bussola, a village |