_Effect of Winds on Health._--Save only in so far as it necessarily raises and transports dust, and that the latter may consist not only of mineral particles but may contain also deleterious organic matter and the germs of certain diseases, the action of wind, being equivalent to so much the freer ventilation, may always be considered desirable in hot climates. Given a free current of air, the highest air temperatures are borne with comparative comfort, whereas in stagnant air the sense of oppression is unbearable. The existence of a steady breeze from a known direction also makes it possible to artificially cool houses by placing in the doorway facing the direction of the wind wetted mats, which cool the air passing through them by the agency of evaporation. It further makes it possible to live in comfort without the use of punkahs and other artificial means of keeping up a free current of air; indeed, as a matter of fact, the habitability of places situated in the Tropics depends largely on the amount and continuity of the breeze. As has already been remarked, the amount of dust present in the atmosphere depends mainly, in the first place, on dryness of the air, and in the second on the force of wind; but it is also a fact that under certain conditions, dependent probably on electrical manifestations, a very still atmosphere may yet carry in suspension a large amount of dust, and its presence may become inimical to health by causing irritation to the respiratory organs as well as to the eyes and lining membrane of the nostrils. This is specially liable to be the case when the suspended particles are sharp and angular, as in the case of the micaceous dust, with which, during the dry, hot weather, the air is often loaded in certain sub-Himalayan stations, producing in many persons soreness of the eyes and troublesome, dry cough. Systematic observations on the amount of solid matter suspended in the air are as yet entirely wanting, but there can be little doubt that they would, if available, be valuable to the student of public health; for the high mortality among tradesfolk whose occupations involve the respiration of a constantly dusty atmosphere is thoroughly well known, and it is most improbable that what is true of dusty trades is not also true of dusty places. Although generally admitted, especially as an article of popular belief, the influence of the varying electrical states of the atmosphere is as yet so ill-understood that nothing definite can be stated on the subject. SECTION II. On the Special Characteristics of the Climates of Certain Hot Countries. There is perhaps no one topic of human conversation that comes in for more discussion than that of the weather, and yet it is no exaggeration to say that there is no other as to which exact information is so scanty or so little accessible, and it is believed that even the following scanty notes are more complete than can be found in any one work in the English language.