168 COMPOSITION OF VEGETABLES. 
with chlorine, forming chloride of sodium or common 
salt. 
Iodine (forming, with hydrogen, Hydriodie Acid). 
- Potassium (in union with oxygen, in the state of Potassa). 
Sodium (in union with oxygen, forming Soda). 
Calcium (with oxygen, forming Lime). 
Magnesium (with oxygen, forming Magnesia). 
Silicum (with oxygen, forming Silica). 
Aluminum (with oxygen, forming Alwnina). 
Iron (with oxygen, forming Ozide of Iron). 
Manganese (with oxygen, forming Oxide of Manganese). 
The last eight are metals, existing in vegetables in the 
state of oxides, mostly in union with some acid, and in very 
small quantities. 
622. Many plants contain silica. Clover yields sulphate _ 
of lime in its ashes. Nitrate of potassa is found in the sap 
of the sun-flower ; and nitrate of soda in barley. Oats and 
some seeds yield a little phosphate of lime. Sea weeds and 
plants growing near the shore contain a considerable quantity 
of chloride of sodium. 
623. The sap is the watery fluid found in the alburnum ;— 
it varies much in different trees ; it always contains a large” 
quantity of water ; and generally some sugar and mucilage, 
some acetate of potassa, carbonate of lime, acetate of lime, 
~ or acetate of alumina, and sometimes an uncombined acid. — 
Sometimes tannin and gallic acid are present in the sap 
but sugar and mucilage are the principal vegetable ingre- 
dients. Mr. Adams found twelve fluid ounces of the sap_ 
of the rose tree to contain 
Oxalate of Lime, : : . 2.900 grains. 
Acetate of Lime, 3 yes RO 
Acetate of Potassa, . : 5 OF 
Gum and Extractive, 2 ery | 
Sugar, &c. (soluble in Alcohol), i Ok 
MO ae oe ; = ~.. 0353 
