UMBEL. 



and milk ducts, all of which first unite into 

 eight or ten principal ducts, and these again 

 into one, which perforates the skin of the teat 

 at its apex. The granular part is the secreting 

 organ. 



UMBEL. In botany, a particular arrange- 

 ment of the flowers in certain plants, of which 

 the carrot is a familiar example ; the pedun- 

 cles and pedicles spring from a common centre, 

 and rise till they form a somewhat flat tuft. 

 The umbel is a loose inflorescence, the primary 

 axis of which is short, and the secondary long; 

 and the umbel becomes .compound when the 

 secondary axes are developed, in the same 

 manner as the primary. Both the primary and 

 the secondary umbel is generally furnished 

 with bractes at the point of its divergence. 

 The secondary umbel is termed umbdlule. The 

 difference between an umbel and a corymb is, 

 that in the latter the flowers form a flat head, 

 the secondary axes arising alternately from 

 different points of the primary, not, as in the 

 former, springing from a common centre. See 

 INFLORESCENCE. 



UMBELLIFEROUS PLANTS (Umbelli- 

 ferce). An extensive group of useful plants, 

 including those well-known garden vegetables 

 parsley, celery, carrots, fennel, caraway, cori- 

 ander, dills, anise, lovage, angelica, eryngo, 

 samphire, hemlock. The name of the class 

 was given from a fanciful resemblance to 

 some parts of an umbrella or parasol. The 

 flower-stem divides at the top into a number 

 of short, slender branches, which all run from 

 a common point or centre like the rays of an 

 umbrella from the ring sliding up and down 

 the stick. The class, though containing so 

 many useful plants, has many possessed of 

 extremely poisonous qualities, such as hem- 

 lock, the fool's parsley (JEthusa cynapium, PI. 

 10, g), dropwort, &c. The blossom of the elder 

 resembles at first sight those of umbelliferous 

 plants, to which, however, the elder does not 

 belong, because the rays of the flower do not 

 proceed from a common point, some being 

 higher and some lower. 



UNDERWOOD. A term applied to coppice, 

 or any wood not accounted timber. See COP- 

 PICE, FOREST, and PLANTATION. 



URINE. A saline fluid secreted from the 

 blood of animals by the kidneys, collected in 

 the urinary bladder, and emitted by the canal 

 of the urethra. Urine differs in different ani- 

 mals, and varies in its characters, according to 

 the kind of food employed. The usual salts 

 contained in it are, sulphates, phosphates, and 

 chlorides, all of which are fertilizing sub- 

 stances. The urine also of oxen and horses is 

 alkaline ; it undergoes decomposition less ra- 

 pidly than that of carnivorous animals : it 

 contains hippurates, but no lithic acid, that 

 substance which forms red gravel in man. 

 Hippuric acid contains 7 per cent, of nitrogen. 

 Urine, therefore, is of much use as a manure, 

 improving most kinds of soil. Columella has 

 asserted that, stale, it is excellent for the roots 

 of trees. And Hartlib commends the Dutch 

 for preserving the urine of cows as care- 

 fully as they do the dung, to enrich their 

 lands. 



1074 



VEGETABLE CHEMISTRY. 



It is a fluid capable of being employed with 

 great benefit both on meadows and on arable 

 land. See LIQ.UID MANURE and NIGHT-SOIL. 



URITH. Provincially the etherings or bind- 

 ings of hedges. 



USTILAGO (from ustus, scorched appear- 

 ance). A genus of fungi, parasitical, which 

 are found preying upon the cereal and other 

 grasses. See SMUT. 



V. 



VALLESNERIA (Spiralis). This plant 

 grows very abundantly from the bottoms of 

 fresh water rivers and lakes over the whole 

 United States, where the flow of water is not 

 very rapid. It goes by the different names of 

 eelgrass, tapegrass, and channehveed. It is 

 upon the roots of this grass, or a native spe- 

 cies of vallesneria, that the canvass-back 

 duck feeds, and to which its peculiarly delicate 

 flavour is ascribed, by Wilson, the ornitho- 

 logist. 



VALUATION. See APPRAISEMENT. 



VEGETABLE CHEMISTRY is that branch 

 of the science of chemistry which relates to 

 vegetable substances. Under the heads 

 ANALYSIS, CHEMISTRY, ORGANIC CHEMISTRY, 

 GASES, EARTHS, WATER, SALTS, &c., I have 

 endeavoured to include all the facts supplied 

 by this important science for the assistance 

 of the farmer with which I am acquainted; 

 I shall, therefore, merely insert in this place 

 the chemical analysis of the inorganic sub- 

 stances found in several of the commonly cul- 

 tivated crops of the farmer ; and this I take 

 from p. 318, of the valuable Lectures on Agri- 

 cultural Chemistry and Geology, by J. F. Johnston j 

 see also Liebig's Organic Chemistry. 



Besides the elements of the organs of plants, 

 other substances, obtained from inorganic na- 

 ture, are necessary for certain organs destined 

 to special functions peculiar to each family of 

 plants. In the ashes of the plants left after 

 burning them, these substances are found. 

 Almost all plants contain acids, in combination 

 with soda, potassa, lime, alumina, or magnesia. 

 The quantity of these salts varies at different 

 periods of the growth of the plant : thus unripe 

 grasses contain more bitartrate of potassa than 

 the ripe, and the potato more potassa before it 

 blossoms than afterwards. The nature of a 

 soil, as has already been detailed, alters the 

 quantity of salts found in plants. The Salsola 

 kali, raised from seeds of plants near the sea, 

 in an inland garden, contains both potassa and 

 soda ; but the plants from the seed of this con- 

 tain potassa only. But these facts are detailed 

 under the head SALTS, &c. 



In examining the results of these analyza- 

 tions, the farmer must remember, that the acids 

 and their bases do not exist in plants in aa 

 uncombined state, but in combination with 

 each other ; that is, as salts. 



1. Of the Jlsh of Wheat. According to the 

 analysis of Sprengel, 1000 Ibs. of wheat leave 

 11-77 Ibs. and of wheat straw 35-18 Ibs. of ash, 

 consisting of 



