Sentence:  There are sulphurous Vapours which infect the Vegetables, and render the Grass unwholsom to the Cattle that feed upon it: Miners are often hurt by these Steams. Observations made in some of the Mines in "Derbyshire", describe four sorts of those <WSD>Damps</WSD>. 
Meaning of the word marked with <WSD> tags:  A gaseous product, formed in coal mines, old wells, pits, etc.