former case, to the presence of ozone in the sea air. The fact that holiday-makers are able to endure the smell of slowly-decaying seaweed with a dash of putrescent fish about it, which is called "sea-air," without injury, and even to pick up health in the presence of it, is more due to the absence of carbon dioxide and other deleterious gases of the towns than to anything else. The beneficent effects of country air are practically all due to the power possessed by green vegetation of superoxygenating the surrounding air. The atmosphere of cities, or at all events of city homes, will presently be freed from the products of combustion and respiration, and endowed with a slightly-increased proportion of oxygen, by artificial means. And especially in bedrooms, rendered to-day stuffy and unhealthy by the idiotic fear of night air which an effete tradition has handed down to us, will this reform be in evidence. Prudent people to-day insist on large bedroom windows—preferably of the French-door pattern—and keep them wide open all night. But this is attended by inconveniences in cold and wet weather; and while our grandchildren will still keep their windows open all night in all weathers, they will not be content with this alone. There will be a chemical apparatus hidden away in some corner, or built into the wall, which will absorb carbon dioxide and at the same time slowly give off a certain amount
