in the ConJhiiSt'ion of C'llies, 237 



to a powder. The pavements for the foot paflcngcrs are of 

 large marbles ; and, in many parts, the foil is calcareous 

 too: in other parts, as the ftreets are paved with fmall 

 round ftones or pehbles, the accumulation of the calcareous 

 pnwder makes a [Iratum above the furface of the ftreets and 

 public places. When the wind blows hard, there is fo great 

 a quantity of calcareous powder flying about that it is in- 

 conniiudious to the eyes, and fonietimes is fo fine that it 

 comes into the houfes even when the windows and fuflies 

 are ibut up. 



" Now, to v^hat can I impute the heahhinefs of that city 

 but the quality of its calcareous earth ? which neutralizes the 

 putrid exhalations, or feptic acid, which impregnates the 

 atmofphere, and thus prevents its bad and fatal etlefts, pre- 

 ferving that city, which otherwife would be the fountain of 

 peftilence, and the anti-chamber of death. 



" As no other caufe can be difcovcred of the healthlnefs o( 

 Lifbon, amongft its continual putrid infection, rccourfe may 

 be had to the climate, and to the temperature of the atmo- 

 fphere : but I believe it can be fufiicicntly proved, that the 

 caufe is the influence of the calcareous earth, and not of the 

 climate; becaufe, if this falubrity was owing to the climate, 

 all the neighbourhood of Lifbon, which enjoys the fame cli- 

 mate, would enjoy the fimie healthinefs : but this is not the 

 cafe. On the oppofite bank of the Tagus, over a^ainft Lif- 

 bon, there are. three or four villages, called Almada, Capa- 

 rica, and CaflTilhas, fituated on fmall hills, and furrounded 

 by beautiful farms: the buildings there are in general of 

 filiceous Itones, the foil is fandy and in fome parts clayey, 

 and the (Ireets in thefe villages infinitely cleaner than ia 

 Lifbon ; but intermittent and remittent fevers prevail in 

 thcfc villages and their neighbourhoods almofl; every fum- 

 mcr, while in the mean time Lilbon is perfedtly free. Near 

 the other part of the river, in the neighbourhood of Lifbon, 

 on the Hiore of the ocean, there are other fmall villaffcs, as 

 Cintra and CoUarcs, from whofc neighbourhoods the ftone 



of 



