variation of the height of the _Mercury_ will be made exceeding visible by the motion to and fro of the small Index KL. But this is but one way of discovering the _effluvia_ of the Earth mixt with the Air; there may be perhaps many others, witness the _Hygroscope_, an Instrument whereby the watery steams volatile in the Air are discerned, which the Nose it self is not able to find. This I have describ’d in the following Tract in the Description of the Beard of a wild Oat. Others there are, may be discovered both by the Nose, and by other wayes also. Thus the _smoak_ of burning _Wood_ is _smelt_, _seen_, and sufficiently _felt_ by the eyes: The _fumes_ of burning _Brimstone_ are _smelt_ and discovered also by the destroying the Colours of Bodies, as by the _whitening of a red Rose_: And who knows, but that the Industry of man, following this method, may find out wayes of improving this sense to as great a degree of perfection at it is in any Animal, and perhaps yet higher. ’Tis not improbable also, but that our _taste_ may be very much improv’d, either by _preparing_ our taste for the Body, as, after eating _bitter_ things, _Wine_, or other _Vinous liquors_, are more sensibly tasted; or else by _preparing_ Bodies for our tast; as the dissolving of Metals with acid Liquors, make them tastable, which were before altogether insipid; thus _Lead_ becomes _sweeter_ then Sugar, and _Silver_ more _bitter_ then Gall, _Copper_ and _Iron_ of most _loathsome_ tasts. And indeed the business of this sense being to discover the presence of dissolved Bodies in Liquors put on the Tongue, or in general to discover that a fluid body has some solid body dissolv’d in it, and what they are; whatever contrivance makes this discovery improves this sense. In this kind the mixtures of Chymical Liquors afford many Instances; as the sweet Vinegar that is impregnated with Lead may be discovered to be so by the affusion of a little of an _Alcalizate solution_: The bitter liquor of _Aqua fortis_ and _Silver_ may be discover’d to be charg’d with that Metal, by laying in it some plates of Copper: ’Tis not improbable also, but there may be multitudes of other wayes of discovering the parts dissolv’d, or dissoluble in liquors; and what is this discovery but a kind of _secundary tasting_.