ATMOSPHERE IN RELATION TO HUMAN LIFE AND HEALTH. 281 



the impracticability of colonizing the equatorial zone with the races 

 of the cooler temperate regions. Even the high stations on the hills, 

 where the temperature may not be above that of the home country, 

 are not sufficiently favorable to the continuance of the family and to 

 permanent settlement. The air, though cool at niglit and agreeably 

 warm by day, is somewhat too much rarefied, and the sun shines verti- 

 cally. At 7,500 feet the pressure and density of the air are lessened 

 by one-fourth, and the sun's heat increased by many degrees. 



Australia is not yet proved to be equal to the Mother Country as a 

 permanent home for the Anglo-Saxon race; indeed, there is some evi- 

 dence that the British standard is uot maintained, but this is largely 

 accounted for by causes which may be considered within human 

 control. 



Hot climates are not favorable to emigrants above 44 years of age or 

 to children under 10, and field labor can not well be undertaken. 



While Europeans visiting hot, moist climates are apt to be attacked 

 in the bowels, the inhabitants of hot climates visiting Europe and 

 North America are especially attacked by, and often succumb, to dis- 

 eases of the respiratory organs. The cold countries are unfavorable 

 to the establishment of tropical races. A similar relation seems to 

 hold here between cold and respiratory diseases and heat and bowel 

 diseases, as we have seen to prevail in winter and summer in temperate 

 climates, but the effect is accentuated when the subject is unacclnna- 

 tized. That the natives of tropical Africa can increase and multiply 

 in subtropical or moderately warm climates is proved by their increase 

 in the Southern States of North America. 



Tropical islands are not in general well adapted for colonization by 

 northern Europeans, for though their climate is more moderate than 

 that of the mainland and tempered by sea breezes, fever often infects 

 the valleys, and the moisture of the atmosphere has a relaxing influ- 

 ence. But many islands not considered wholesome would be far more 

 congenial if proper hygienic measures were taken and the most suit- 

 able food and clothing habitually used. The Sandwich Islands are 

 favorable for settlement, and may be compared with tropical highlands 

 of moderate elevation. 



The most remarkable instance of the permanent settlement of English 

 people in the tropics is that of the inhabitants of the Barbados and of 

 Tuagua, one of the Bahama Islands. The former are descendants of 

 rebels sent from England for slavery between 1050 and 1700. They 

 have survived through conditions of great misery and severe exposure. 

 The islanders are now chiefly occupied in fishing. Deterioration there 

 has been, but this may fairly be ascribed to poverty and improper food 

 rather than to climate. In Tuagua the people, some of whom belonged 

 to families settled there since the time of Charles II, appear to have 

 maintained somewhat better health and physique. 



It is noteworthy how in some circumstances a seemingly small change 

 of climate does harm or good and in others a very great change has no 



