94 



A HISTORY OF 



rather by the means which he has discovered 

 pf obviating their effects, than by the ap- 

 parent strength of his constitution. Most 

 other animals can bear cold or hunger better, 

 endure greater fatigues in proportion, and 

 are satisfied with shorter repose. The varia- 

 tions of the climate, therefore, would pro- 

 bably affect them the less, if they had the 

 same means or skill in providing against the 

 severities of the change. However this be, 

 the body of man is an instrument much more 

 nicely sensible of the variations of the air, 

 than any of those which his own art has pro- 

 duced ; for his frame alone seems to unite all 

 their properties, being invigorated by the 

 weight of the air, relaxed by its moisture, 

 enfeebled by its heat, and stiffened by its 

 frigidity. 



But it is chiefly by the predominance of 

 some peculiar vapour, that the air becomes 

 unfit for human support. It is often found, 

 by dreadful experience, to enter into the 

 constitution, to mix with its juices, and to 

 putrefy the whole mass of blood. The ner- 

 vous system is not less affected by its opera- 

 tions; palsies and vertigoes are caused by 

 its damps ; and a still more fatal train of dis- 

 tempers by its exhalations. In order that 

 the air should be wholesome, it is necessary, 

 as we have seen, that it should not be of one 

 kind, but the compound of several sub- 

 stances; and the more various the compo- 

 sition, to all appearance the more salubrious. 

 A man, therefore, who continues in one place, 

 is not so likely to enjoy this wholesome va- 

 riety, as he who changes his situation ; and, 

 if I may so express it, instead of waiting for 

 a renovation of air, walks forward to meet 

 its arrival. This mere motion, independent 

 even of the benefits of exercise, becomes 

 wholesome, by thus supplying a great variety 

 of that healthful fluid by which we are sus- 

 tained. 



A thousand accidents are found to increase 

 these bodies of vapour, that make one place 

 more or less wholesome than another. Heat 

 may raise them in too great quantities ; and 

 cold may stagnate them. Minerals may give 

 off tHeir effluvia in such proportion as to 

 keep away all other kind of air; vegetables 

 may render the air unwholesome by their 

 supply ; and animal putrefaction seems to 



furnish a quantity of vapour, at least as 

 noxious as any of the former. All these 

 united, generally make up the mass of respi- 

 ration, and are, when mixed together, harm- 

 less ; but any one of them, for a long time 

 singly predominant, becomes at length fa- 

 tal. 



The effects of heat in producing a noxious 

 quality in the air, are well known. Those 

 torrid regions under the Line are always un- 

 wholesome. At Senegal, I am told, the na- 

 tives consider forty as a very advanced time 

 of life, and generally die of old age at fifty. 

 At Carthagena," in America, where the heat 

 of the hottest day ever known in Europe is 

 continual, where, during their winter season, 

 thesedreadful heats are united with a continual 

 succession of thunder, rain, and tempests, 

 arising from their intenseness, the wan and li- 

 vid complexions of the inhabitants might make 

 strangers suspect that they were just recover- 

 ed from some dreadful distemper; the ac- 

 tions of the natives are conformable to their 

 colour; in all their motions there is some- 

 what relaxed and languid ; the heat of the 

 climate even affects their speech, which is 

 soft and slow, and their words generally 

 broken. Travellers from Europe retain their 

 strength and ruddy colour in that climate, 

 possibly for three or four months ; but after- 

 wards suffer such decays in both, that they 

 are no longer to be distinguished from the 

 inhabitants by their complexion. However, 

 this languid and spiritless existence is fre- 

 quently drawled on sometimes even to eighty. 

 Young persons are generally most affected 

 by the heat of climate, which spares the 

 more aged ; but all, upon their arrival on the 

 coasts, are subject to the same train of fatal 

 disorders. Few nations have experienced 

 the mortality of these coasts, so much as our 

 own ; in our unsuccessful attack upon Car- 

 thagena, more than three parts of our army 

 were destroyed by the climate alone ; and 

 those that returned from that fatal expedition, 

 found their former vigour irretriev;>l ty gone. 

 In our more fortunate expedition, which gave 

 us the Havannah, we had little reason to 

 boast of our success; instead of a third, not 

 a fifth part of the army were left survivors of 



Ullo, vol. i. p. 42. 



