92 



A HISTORY OF 



of salts and menstruums ; and, therefore, it is 

 capable of dissolving all kinds of bodies. It 

 is well known, that copper and iron are 

 quickly covered, and eaten with rust; and 

 that, in the climates near the equator, no art 

 can keep them clean. In those dreary coun- 

 tries, the instruments, knives and keys, that 

 are kept in the pocket, are nevertheless 

 quickly incrusted ; and the great guns, with 

 every precaution, after some years, become 

 useless. Stones, as being less hard, may be 

 readily supposed to be more easily soluble. 

 The marble of which the noble monuments 

 of Italian antiquity are composed, although 

 in one of the finest climates in the world, 

 show the impressions which have been made 

 upon them by the air. In many places they 

 seem worm-eaten by time; and, in others, 

 they appear crumbling into dust. Gold alone 

 seems to be exempted from this general state 

 of dissolution ; it is never found to contract 

 rust, though exposed never so long : the rea- 

 son of this seems to be, that sea-salt, which 

 is the only menstruum capable of acting up- 

 on, and dissolving gold, is but very little mix- 

 ed with the air ; for salt being a very fixed 

 body, and not apt to volatilize, and rise with 

 heat, there is but a small proportion of it in 

 the atmosphere. In the elaboratories, and 

 shops, however, where salt is much used, and 

 the air is impregnated with it, gold is found 

 to rust as well as other metals. 



Bodies of a softer nature are obviously de- 

 stroyed by the air.* Mr. Boyle says, that 

 silks brought to Jamaica, will, if there expo- 

 sed to the air, rot, even while they preserve 

 their colour ; but if kept therefrom, they both 

 retain their strength and gloss. The same 

 happens in Brazil, where their clothes, which 

 are black, soon turn of an iron colour; 

 though, in the shops, they preserve their 

 proper hue. b In these tropical climates also, 

 such are the putrescent qualities of the air, 

 that white sugar will sometimes be full of 

 maggots. Drugs and plaisters lose their vir- 

 tue, and become verminous. In some places 

 they are obliged to expose their sweetmeats 

 by day in the sun, otherwise the night air 

 would quickly cause them to putrefy. On 

 the contrary, in the cold arctic regions, ani- 



a Button, vol. iii. p. 62. 



mal substances, during their winter, are ne- 

 ver known to putrefy ; and meat may be kept 

 for months without any salt whatsoever. This 

 experiment happily succeeded with the eight 

 Englishmen that were accidentally left upon 

 the inhospitable coasts of Greenland, at a 

 place where seven Dutchmen had perished 

 but a few years before ; for killing some rein- 

 deer for their subsistence, and having no salt 

 to preserve the flesh, to their great surprise 

 they soon found it did not want any, as it re- 

 mained sweet during their eight months con- 

 tinuance upon that shore. 



These powers, with which air is endued 

 over unorganized substances, are exerted in 

 a still stronger manner over plants, animals 

 of an inferior nature, and, lastly, over man 

 himself. Most of the beauty, and the luxuri- 

 ance of vegetation, is well known to be de- 

 rived from the benign influence of the air; 

 and every plant seems to have its favourite 

 climate, not less than its proper soil. The 

 lower ranks of animals, also, seem formed for 

 their respective climates, in which only they 

 can live. Man alone seems the child of every 

 climate, and capable of existing in all. How- 

 ever, this peculiar privilege does not exempt 

 him from the influences of the air; he is as 

 much subject to its malignity as the meanest 

 insect or vegetable. 



With regard to plants, air is so absolutely 

 necessary for their life and preservation, that 

 they will not vegetate in an exhausted re- 

 ceiver. All plants have within them a quan- 

 tity of air, which supports and agitates their 

 juices. They are continually imbibing fresh 

 nutriment from the air, to increase this store, 

 and to supply the wants which they sustain 

 from evaporation. When, therefore, the ex- 

 ternal air is drawn from them, they are no 

 longer able to subsist. Even that quantity 

 of air which they before were possessed of, 

 escapes through their pores, into the ex- 

 hausted receiver; and as this continues to be 

 pumped away, they become languid, grow 

 flaccid, and die. However, the plant or flow- 

 er thus ceasing to vegetate, is kept, by being 

 secured from the external air, a much longer 

 time sweet than it would have continued, had 

 it been openly exposed. 



b Buffon, vol. iii. p. 68, 



