there is any considerable depth of it, that at the bottom is likely to be freer from organic impurities than that near the surface, and it will be better if drawn from the bottom by a pump than from the surface by a bucket, though the latter will probably taste the best from its being better aired. The water from drive wells is safer than that from dug wells, on account of being drawn from a greater depth beneath the surface of the underground water, and, so, less likely to be contaminated with surface impurities.

RAIN-WATER.

This is liable to be contaminated by gases absorbed from the air, by dust and dirt which accumulates on roofs, and by the smoke which escapes from chimneys. It is usually soft-water, and the impurities, though disagreeable, are not dangerous, and when the water is collected in cisterns, which are securely covered so as to keep out surfacewater, they furnish a safe supply for domestic use. Cisterns should be deeper than they are usually made, and more capacious. They would fill with cold water during the winter, and as the summer rain is warmer, it will remain on top of the winter water in the cistern, and if there is any overflow it will be of the warm water and not of the cold. In this way cistern water can be stored so as to be always cool, and from its low temperature it is nearly free from any changes which the organic matter in it might undergo at the usual summer heat. Filtering, however, improves rain-water. It holds back some of the impurities and leaves the water clear and bright. Filters for rain-water are made in a great many ways. They have been made of sand, of charcoal, of animal charcoal, of oxide of iron, of porous sandstone, of unglazed brick, etc. The filtering substance being placed in such a way as to require the water to pass slowly through it before being drawn out for use. A solid brick wall, laid carefully in cement mortar, makes a good filter. The bricks should be rather under-burned, and extending through from one side of the wall to the other, and the faces of the wall not covered with mortar. Water will filter through such a wall fast enough for the supply of a family, and if the rain all enters the cistern upon one side of the wall and is drawn out upon the other side, the water is clean and sufficiently pure. The storing of pure water in this way, for drinking, is worthy of more attention than it has received, and the quantity which can be stored from roofs is sufficient for all family use.

Wherever only unfiltered water from streams or wells or cisterns is to be had, its quality may be much improved by passing it through the small filters which are prepared for household use. There are great numbers of these, and it would not be profitable to discuss their merits at this time. The common bag of cotton flannel, or flannel, tied on the faucet of the water-pipe will greatly improve the appearance of drinking water, and will strain out many disagreeable objects. A tube or box with sponge in it will also be satisfactory in clarifying turbid water, and like the bags it is easily and quickly washed and replaced. Granulated animal charcoal in boxes or vessels where the water can filter slowly through it, improves its appearance and quality. Some of the best house filters are made essentially of this substance. Vessels having in them and near the bottom horizontal partitions made of porous brick or sandstone, so that the water can filter slowly through, and be drawn off below, serve a very useful purpose.

There are many filters for clarifying water for manufacturing purposes; their action is mechanical, and their description would be out of place here.

While the benefits arising from the filtration of water have been proved by many satisfying experiments and experiences, the chemical or mechanical changes which it undergoes are not well understood. By some, the changes which it undergoes are said to be due to oxidation, that is, to a chemical combination of the impurity with oxygen from the air, by which the original is destroyed and some new and harmless one is produced. Every chemist knows that substances which are porous or in fine grains have the power of attracting air or oxygen to their surfaces, and in the case of the porous substances, the amount absorbed is equal to a great many times the volume of the porous substance itself. This is notably true of animal charcoal, but it is very observable in sand or in fragments of glass. The organic matter in water, though it may be very active and dangerous, is in extremely small quantity, so that the amount of oxygen needed to consume it is very little. When the filters cease to act it is said to be because the oxygen on them is exhausted, and if they are taken out, cleansed, dried and put in their places again, they act as efficiently as at first. This explanation is plausible, and, though not entirely demonstrated, it applies to the known facts more closely than any other. Numerous chemical examinations have been made of samples of water before and after filtration. They generally show a small diminution

in the amounts of organic matter, but not by any means sufficient to explain the changes which appear to have taken place in the properties of the water. The dangerous effects of organic matter in water are due not so much to its quantity as to its quality. It may well be that in the process of filtration its dangerous properties are to some extent destroyed, while the elements of its substance still remain. This explanation seems consistent and may be accepted till some better one is found. The sanitary benefits of the filtration of water are so well sustained by experience, that we must advocate the adoption of plans for that end wherever water that is liable to contamination is used.

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NOTES ON POPULAR HEALTH RESORTS.

BY THE SECRETARY OF THE BOARD.

The sea-coast of New Jersey has not only become the most popular resort for the American people, but has so rapidly increased in permanent residents as to have cities and towns and villages which have an increasing population each year, and which are destined to grow as rapidly as towns in other portions of the State. Indeed, some of them have already so far established their claims as serviceable for winter resorts as to assure a sustained population of this class, even although as to individuals it may be transient. Both as a material interest of the State and as a care of the public health, the Board early recognized the duty of a close and accurate observation of all places offered to the public as having sanitary inducements. We claimed the duty of close inspection, of apprisal of those pecuniarly concerned as to defects either through carelessness or ignorance, and of report to the public if these defects were not remedied. We believed that while owners should not be hastily attacked, and while no sensational statements should be made, the policy of long concealment should be ignored. No one can realize as do members of this Board the need there was of such examination and advice, and the results which have been secured. We can point to place after place where our first visits were occasions of persuasion, of protest, and sometimes of local denunciation, but where Health Boards, and often owners, became convinced of the correctness of views expressed, and proceeded, with greater or less speed, to remedy the evils complained of. For any health officer, a sanitary inspection along the coast to-day is in most cheering contrast with the experience of six years ago. Not that all was then bad, or that all is now good, but there has been a great increase of intelligence as to necessity and methods; and there is a general determination to have the sanitary arrangements complete. This has not been merely as to the most leading and vital concerns,