isB3ss9Sl CHAPTER II. ON THE SELECTION OF BUILDING STONES, WITH SPECIAL REGARD TO CLIMATE AND THE NATURE OF THE ATMO SPHERE. The climate of countries where building stones are employed in modern times, may be conveniently di vided into dry and humid; and as regards atmo sphere, into pure and smoky, or acid. Rainless regions, being exceptional, may be dismissed with the remark that almost any kind of stone will be found durable in them. Passing, therefore, to the consideration of the subject under the heads above named, we commence with climates which may be called ‘ dry,’ in which rain is only periodical. Dry climates. In such climates the rain falls but sparingly, and only periodically ; the greater part of the year being rainless, and the temperature warm. Countries which enjoy such climates are tropical or sub-tropical, and include portions of Cen tral and Southern Europe, Asia Minor, India, Australia, and large tracts of Central America, both north and south of the Equator.