Page:The New International Encyclopædia 1st ed. v. 18.djvu/859

* SWEET POTATO. 751 SWELL SHARK. prepared bed and when about four inches tall planted 18 inches asunder in rows SV^ feet apart in the field; the later vine cuttings, which are commonly used in the Gulf States and as far north as Virginia, require from 'JO to 105 days to mature their roots. The crop grows best in a warm, sandy, well-drained soil. It requires clean cultivation. Earl}- digging yields only one-half to two-thirds as nuich as may be obtained from the matured crop, which averages from 250 to 275 bushels per acre. The roots should be har- vested before frost and when the ground is dry. The roots must be stored in a rather warm, dry place, as otherwise heay losses are almost sure to occur from rotting. The so-called 'yams' grown in the United States are all sweet potatoes. The most serious diseases of the sweet potato destroy the tleshy roots. The black rot {Cera- toci/stis fimhriata), which appears as greenish black, irregular spots which increase in size and eventually destroy the whole root, may be spread through planting diseased tubers in the seed bed or through the presence of the fungus in the soil. At the New .Jersey Experiment Station sulphur in the soil has been used with success as a pre- ventive. Dry rot {Phoma hatalw) dries, wrinkles, and fills the roots with powder. It at- tacks the whole root in the field. Rotation of crops and destruction of diseased ni.aterial are recommended as preventives. A soft rot (Rlii^opus nigricans) attacks stored roots, usu- ally commencing at places where the skin has been broken. Since moisture favors its spread, sweet potatoes should be stored in well-ventilated, dry rooms. A leaf spot {Phi/llosticta batati- colli) often attacks and turns the foliage white, and a leaf mold {Cystoptis ipomcece-paiiduranw) turns the leaves, especially the older ones, brown. Spraying with Bordeaux mixture or other fungi- cide (q.v.) is recommended for these last two and the first disease. As ordinarily prepared for the table the skin constitutes on an average 20 per cent, and the edible portion 80 per cent, of the root. The edible portion has the following percentage composition: water, G9.0; protein, 1.8; fat, 0.7; nitrogen-free extract. 27.4; and ash, 1.1 per cent., the fuel value being 570 calories per pound. Like ordi- nary potatoes, sweet potatoes are a succulent food, the chief nutrient being carbohydrates, the principal of which is starch. Sugars are also found, 2.5 per cent, cane sugar and 3.4 per cent, invert sugar being the average amount found in a large number of analyses. In addition to the quantities consumed in the fresh state, sweet potatoes are also canned and evaporated. They are sometimes fed to farm animals, especially pigs. To secure the greatest profit the pigs should harvest the crop and some nitrogenous feed like cowpeas should also be fed. See Plate of Yam, Sweet Potato, etc. SWEET-POTATO INSECTS. The leaves of the sweet potato are punctured by a small bronzed flea-beetle {ChcFtocnemn cotjfinis), which eats channels along the veins soon after the plants have been set out and causes the leaves to shrivel. The most serious of the insect ene- mies of the crop are several species of tortoise- beetles. (See Toktoise-Reetle.) Among the commonest species are the two-striped tortoise- beetle {Cassida bivittata), which is pale yellow and has two black stripes on each wing-cover. The larva is dirty yellowish white and covers itself with cast skins and excrement. It gnawa irregular holes in the leaves underneath which it transforms to pupa. The golden tortoise- beetle {Coplocycla aurichalcea), which is more abundant, resembles gold tinsel and is beauti- fully resplendent. The larva is dark brown and feeds like the previous species. Arsenical sprays have been recommended. SWEET-SCENTED SHRUB. See Cai,y- CA>II11S. SWEET SOP {Ancma squamosa). A bush or small tree ot the natural order Anonaceaj, a na- tive of tropical America and introduced in other warm countries. The scaly greenish fruit has a soft, somewhat mealy, sweet, and luscious pulp with a musky aromatic odor and flavor. It is much used, generally raw, but sometimes cooked, and has proved valuable during famines in Hindustan. SWEET SULTAN. A garden plant. See Centairea. SWEET VERNAL GRASS. A slender European grass {.Intlioxantliuin odoratum), about IS inches tall and bearing a loose cylindri- cal spike of flowers. It is noted for its pleasing odor due to coumarin, which is most noticeable when the plant is in flower. It is often mixed with other glasses to give flavor to hay. but is not considered equal in feeding value to timothy, orchard grass, etc. See Plate of Grasses. SWEET WILLIAM, Wild. See Phlox. SWELL (AS., OHG. swellan, Ger. sclncellen, to swell : possibly connected with Gk. <rafiJeti', saleuein, to toss, Lat. saluin, open sea). A term applied to a local thickening of a mineral de- posit. The phenomenon is not uncommon in many metalliferous veins, and is caused by local expansions of the ore-bearing fissure, due to dynamic action or solution. In coal seams a similar phenomenon is often met with, but the swell here is caused by movements of the floor and roof of the coal bed. SWELL. In music, a set of pipes in an organ, forming a separate department, which arc ca- pable of being increased or d>minished in in- tensity of sound by the action of a pedal, or by a scries of shades or shutters overlapping each other like Venetian window-blinds, within which the pipes in question are inclosed. The first recorded swell organ was made in 1712 by .Jordan, and in 1763 Shudi introduced the so-called Ve- netia swell, but the compass of all the early swells was vers- incomplete. See Oroax. SWELLFISH. One of the many names ap- plied to |>lcctognath fishes, esjiecially of the fam- ily TetraodontidiV. which inflate their bodies with air until they Income globe-like and the spines of their skin rigid, makinc them unplea-:an) morsels for an enemy to swallow. A familiar example is Tetrnodon turriidus. of the Eastern American coast-waters, also called 'swell-toad' and 'puflTer.' Compare Globkfish. See Plate of Plectognath Fishes. SWELL SHARK. A small, voracious pray shark (CatuHiif!' iitcr) of the family Scylliidie, common nn tlic Pacific Coast from central Oali- fornia to Chile, and often taken in lobster-pots. When caught it will inflate its stomach with air,