384 Conjiderations on Vegetable ExtraSli. 



4th, The nlalic acid : il is contained in apples, ftrawber- 

 ries, rafpherries, &c. 



5th, The oxalic acid : it exudes from the hair of vetches. 



6th, The acetous acid. .According to fome ehemifts, it is 

 not always the product of the fermentation known under that 

 name ; it is obtained fometimes by the action of the fulphuric 

 and muriatic acids on vegetable Jubilances. C. Vauqueliu 

 found it in the lap of trees. 



7th, The oxalic acidulum. Thi? is a non-faturated com- 

 bination of the oxalic acid with potafti : it is furniflhed by 

 i'orrel. 



8th, The tartarons acid. It is found cryftallizcd in large 

 quantity on the fides of cafks in which wine has remained $ 

 but it exifts alio in t unarinds, the barberry bufh, &c. 



Thefe acids are either infulated in vegetables or combined 

 with earths, cither calcareous or aluminous, and alkalies. 



To thefe faline combinations, which with the two acidula 

 may be confidered as the real eflential falts of vegetables, we 

 might add other falts which are often found in them : of this 

 kind are the fulphates of potafli and foda, the muriates of 

 potafh and foda, the nitrate of potafh. 



Thefe la(t falts, according to the obfervations of ehemifts, 

 are produces in vegetables merely b\ the power which refides 

 in them, and which have the faculty of compofing them 

 perfeel:, of uniting and combining the principles which can 

 conftitute them, but in different proportions, fmce it may de- 

 pend on a pre-exiiting famine atom. 



Certain plants in which nitrate of potafh is found are 

 fonder of e?rth which contains it : pellitory, in particular, 

 feems to choofe, that it may grow there at its eafe, the bot- 

 tom of a wall well fumrfhed with faltpetre. 



When the kd^ impelled by an impetuous wind, enters 

 through the mouth of a river at a time when it is lefs abun- 

 dant in water; when it penetrates very far into the country 

 through the fmall canals by which it is watered, and drenches 

 with brine the plaits that ufually grow on their banks; thefe 

 plants ceate to have a defrre for inhabiting them ; they die; 

 and their place is (ban fupplied by other vegetables to which 

 this moiflure is fuitcd, neceflary, and indifpen fable. 



This is exactly what has taken place at the mouths of the 

 Kile. One branch in particular of this river, that of Dami- 

 etta, oppofed for fome time, by a peculiar circiuniiance, lefs 

 Fefiftance to the waters of the lea : it received and Itill receives 

 them during that part of the year when it is lowed ; and 

 fuice that period ieveral of the plants which grew in the 



canaJi 



