678 PHILOSOPHICAL TRANSACTIONS. [[anNO 1702. 



volatile oil and essential salt, the seed a volatile oil and salt : but since the roots 

 and leaves have a pungent taste, there is also a volatile salt in them, though the 

 chemists do not observe it. All the parts of carraways have the odour of 

 punaises, except the seed ; from whence I may infer, that the foetid plants have 

 the same principles as the aromatics, viz. a volatile oil and salt ; and this is con- 

 firmed by other foetids which have them, as rue and assafoetida and vulvaria. 

 Peucedanum is described of a bitter acid taste, with the odour of pitch, and 

 must have a volatile salt, though Lemery describes only its essential salt and 

 oil : so in smallage he describes only the essential salt and oil, but its acrid taste 

 manifests the volatile salt. 10. The sweet gums; as manna, sarcocolla, con- 

 tain much oil and essential salt ; though honey and sugar have more essential 

 salt than oil ; by which we may observe how much essential salt is in all sweets, 

 and why they are apt to turn sour and ferment ; and from such sweet gums all 

 sweet plants have their acid and oil on distillation. 1 1. Citrulls, melons, gourds, 

 cucumbers, which are bitter sweets, and very mucilaginous, contain much oil 

 and little salt. 



Since the whole classes of sweet plants contain an oil and essential salt, some 

 more some less of both, the virtues of the several sweet tastes can never be ex- 

 plained by the chemical principles, and no new virtues by them are discovered ; 

 therefore all the advantage we have obtained by these chemical distillations, is 

 only to show the nature of sweetness in general, by discovering the principles 

 contained in sweet plants, and this is a greater advantage to natural philosophy 

 than to physic, to which the tasting of plants is more useful. By the taste we 

 distinguish the sweets into their several classes, and we discern tempers and 

 digestion, and mixture of their principles, and thence easily guess at their 

 effects in animals ; and by the taste we distinguish the different state of both the 

 oil and acid in plants of different sweet tastes ; whereas the chemists observe no 

 difference of the tartar acid, whether it be acerb or vinous, or volatile ; nor of 

 the sweet oils from the bitter and slimy. By the taste we distinguish the acrid 

 and the acid salts, which mix in distillation ; and they are not well distinguished 

 by the chemists. By the taste we discern when the fire makes new products 

 and mixtures, not naturally found in plants ; for in corn, beans, peas, bread, 

 fire produces a volatile salt, not observable in them before : and a volatile salt is 

 drawn from the lees of wine by the fire ; and leven yields also a volatile salt ; 

 whereas before in corn only an oil and acid were observed ; and it is probable 

 that the tartar is volatilised, both by the fermentation and the fire. Coffee is a 

 bean* by its taste and cods, and acquires a volatile salt by roasting ; but Lemery 

 only mentions its oil and fixed salt upon distillation, but the fixed salt is the 



* Coffee is the seed of the berries of the coffea arabica, Linn. Each berry contains 2 seeds. 



