ACER. 



product than belongs to more southern situ- 

 ations. 



Every view that we can take of this 

 interesting subject, every fact within our 

 knowledge, whether drawn from the actual 

 state' of cultivation, or from physiological in- 

 vestigations into the habits, nature, and con- 

 struction of plants, goes to show that plants 

 do become acclimated, both in the natural and 

 artificial way, to a great extent. Enough has 

 been witnessed to prove that plants have a phy- 

 sical conformation, that does accommodate 

 itself to circumstances, and have capacities 

 more extensive than are generally ascribed to 

 them : enough has been realized to encourage 

 farther efforts, and to give us hopes of much 

 future benefit." 



As allied to this subject see Climate, influ- 

 ence of, on the Fruiffulness of Plants.] 



ACCOUNTS, FARM. See FARM ACCOUNTS. 



ACER. The Roman name for a genus of 

 trees, comprehending different species of the 

 large deciduous kind, as the sycamore, &c. 

 See MAPLE TREE. 



ACETIC ACID, and ACETUM, .terms em- 

 ployed to signify Vinegar, which see. 



ACETOSA. See SORREL. 



ACHILLEA. A genus of plants consisting 

 of sixty or seventy species, found exclusively 

 in the colder climates of the northern hemis- 

 phere. They are all herbaceous, perennial 

 weeds of little importance, except to botanists, 

 and are only seen in cultivation in the collec- 

 tions of the curious. 



ACIDS (Lat. acefum , Goth, aceit , Sax. 

 aecet>). Liquids and other substances are 

 called acids, which commonly, but not always, 

 affect the taste in a sharp, piercing, and pecu- 

 liar manner. The common way of trying 

 whether any particular liquor hath in it any 

 acid particles is by mixing it with syrup of 

 [blue] violets, when it will turn of a red colour; 

 but if it contains alkaline or lixivial particles, 

 it changes that syrup green. [The blue liquor 

 obtained by steeping purple cabbage leaves in 

 hot water, is also a convenient test liquor for 

 acids as well as alkalies.] They combine 

 with various earths, alkalies, and metallic ox- 

 ides, and form the peculiar class of bodies 

 called salts. (Todd's Johnson.) 



[In agricultural chemistry, the acids are di- 

 vided into the inorganic and organic. The first 

 kind, or inorganic, are derived from sources 

 wholly mineral. The second kind, or organic, 

 are derived from animal or vegetable orga- 

 nized substances. The sulphuric acid, or oil 

 of vitriol, is one example of a mineral or in- 

 organic acid. It exists abundantly in nature, 

 combined with mineral bases, as iu plaster of 

 Paris, where it is combined with lime, forming 

 the sulphate of lime, or gypsum. Muriatic 

 acid is another very abundant inorganic or mi- 

 neral acid, and abounds in sea-salt, combined 

 with soda, forming the muriate of soda or com- 

 mon salt. Nitric acid, or <K/uafurtis, is another 

 of .this class of acids, existing abundantly in 

 the well known substance called saltpetre, or 

 nitrate of potash. These three constitute the 

 principal inorganic or mineral acids. 



As all vegetables contain acids, these may 

 be regarded as essential to their life. But these 

 22 



ACIDS. 



acids do not always exist in a free state, being 

 generally combined with some of the alkalies or 

 alkaline substances, such as potash, soda, lime, 

 and magnesia. "These bases evidently regulate 

 the formation of the acids, for the diminution of 

 the one is followed by a decrease of the other: 

 thus, in the grape, for example, the quantity of 

 potash contained in its juice is less, when it 

 is ripe, than when unripe ; and the acids, under 

 the same circumstances, are found to vary in a 

 similar manner. Such constituents exist in 

 small quantity in those parts of a plant in 

 which the process of assimilation is most ac- 

 tive, as in the mass of woody fibre ; and their 

 quantity is greater in those organs whose of- 

 fice it is to prepare substances conveyed to 

 them for 'assimilation by other parts. The 

 leaves contain more inorganic matters than 

 the branches, and the branches more than the 

 stem. The potato plant contains more potash 

 before blossoming than after it. 



" Now, as we know the capacity of saturation 

 of organic acids to be unchanging, it follows 

 that the quantity of the bases united with them 

 cannot vary, and for this reason the latter sub- 

 stances ought to be considered with the strict- 

 est attention both by the agriculturist and 

 physiologist. 



"We have no reason to believe that a plant in 

 a condition of free and unimpeded growth pro- 

 duces more of its peculiar acids than it re- 

 quires for its own existence ; hence, a plant, 

 on whatever soil it grows, must contain an in- 

 variable quantity of alkaline bases. Culture 

 alone will be able to cause a deviation. 



"In order to understand this subject clearly, 

 it will be necessary to bear in mind, that any 

 one of the alkaline bases may be substituted 

 for another, the action of all being the same. 

 Our conclusion is, therefore, by no means en- 

 dangered by the existence of a particular al- 

 kali in one plant, which maybe absent in others 

 of the same species. If this inference be cor- 

 rect, the absent alkali or earth must be sup- 

 plied by one similar in its mode of action, or 

 in other words, by an equivalent of another 

 base. 



"Of course, this argument refers only to those 

 alkaline bases, which, in the form of organic 

 salts, form constituents of the plants. Now, 

 those salts are preserved in the ashes of plants, 

 as carbonates, the quantity of which can be 

 easily ascertained. 



"From these considerations wemustperceive, 

 that exact and trustworthy examination of the 

 ashes of plants of the same kind growing upon 

 different soils would be of the greatest import- 

 ance to vegetable physiology, and would decide, 

 whether the facts above mentioned are the re- 

 sults of an unchanging law for each family of 

 plants, and whether an invariable number can 

 be found to express the quantity of oxygen 

 which each species of plant contains in the 

 bases united with organic acids. In all proba- 

 bility, such inquiries will lead to most import- 

 ant results ; for it is clear, that if the produc- 

 tion of a certain unchanging quantity of an 

 organic acid is required by the peculiar nature 

 of the organs of a plant, and is necessary to 

 its existence, then potash or lime must be ta- 

 ken up by it, in order to form salts with this acid 



