Page:The New International Encyclopædia 1st ed. v. 18.djvu/695

* STORAGE BATTERY. 599 STORK. lead is applied mechanically. The former are known as the Plante type, and the latter as the 'pasted' or Faure type. The Plants cell is the simplest form of storage battery. The earliest cells were formed of two lead plates immersed in dilute sulphuric acid in water. The solution should have a specific grav- ity of 1.17 before charging, and as the charge proceeds the specific gravity increases to 1.195 at full charge. At each successive charge the pero.ide formed on the positive plate sinks deeper into the metal, and this action continues until the metal is covered to a sufficient thick- ness to jiroteet tlie lead from electrolytic action. There is no difficulty in forming the positive plate in a Plant6 cell, but with the negative plate the action is very slow. The latter is the great difficulty with all Plants cells. The usual meth- od of forming the spongy lead is to charge the cell, allow it to rest, then reverse the charge through the cell. At each reversal of current the peroxide is liberated at the surface, leaving me- tallic lead in a very finely divided state. The voltage of a lead-sulphuric acid cell is about two volts. The above description is applicable in a general way to all cells of the Plante type, of which there are a great many varieties. Most of the modifications introduced by the different manufacturers are mechanical changes with a view to exposing more surface of lead to the action of the electrolyte. The Plante aceu- nuilator is a very efficient cell when once formed, but the great amount of time it requires for forming is its chief drawback. To avoid the great loss of time consumed in forming the Plants cells, Faure in 1S80 devised the method of pasting a layer of chemically prepared o.ide of lead to the surface of the plates. This was done by spreading the plates with minium, or litharge, made into a thick paste by the addition of acidulated water. After drying these plates were placed in a bath of dilute sulpliuric acid, and then subjected to an electric current. A piece of felt was placed between the plates to prevent the lead salts from disintegrating. After charging, the salt on the positive plate is reduced to pei-oxide of lead, while that on the negative plate is converted into porous le.id. The chief fault of the early Faure cells was the dis- integration of the active material, which would drop away from the plate. Many methods have been devised for holding the active material on the plates, the most common of which is to cast a grid, or plate with cells or perforations, into which the active material is pressed. All the modern cells are made with perforated plates of this description. Besides these two types of ac- cumulators, which are the most important ones, there are a number of others, in which the ele- ments are composed of lead, zinc, copper, etc., none of which are in very extensive use. Storage batteries are employed in many cen- tral stations to aid the dynamos at the time of the maximum output and to act as equalizers or reservoirs of electrical energy. The efficiency varies from 80 to 85 per cent, in laboratory tests, but in commercial pi-actice it is about 70 per cent, or less. The depreciation, however, may be very rapid if the batteries are not op- crated with care. It is very important not to discharge accumulators faster than the rate for which they are built, as it results in the speedy destruction of the plates. They are not well adapted to traction purposes, as the motion of the car jars out the active material from the plates, and in starting the car a liigli rate of discliarge is required. The weight and bulk of accunmlators is also against their use on cars. With light ■N chicles, as well as with delivery wagons and trucks, accumulators have been em- ployed very successfully, while for telephone and telegraph work in large cities they are rapidly supplanting primary cells, the change being at- tended not only with economy, but also with in- creased cleanliness and available space. Consult: Benjamin, ^'oltaic Cell (New York, IS'J'3) ; Treadwell, The Storage Battery (ib., 1898). STORAX (Lat. stnrnx, styrax, from Gk. aripai, sort of fragrant resin, from Heb. sori, heart of the mastic or of the turpentine-tree). A fragrant resinous substance, the styrax of the ancients, obtained from the storax-tree {Styraai ofjianale) of the natural order Styracacea?, na- tive of the Mediterranean region. Storax, which exudes from wounds in the bark and hardens in the air, appears in the form of reddish-yellow, opaque, soft, adhesive tears about the size of a pea, or in dry, brittle masses, wrapped in the leaves of a kind of reed. It has a fragrant odor and an aromatic taste, and was formerly much used in medicine. Benzoin (q.v. ) is the product of a species of Styrax. Liquid storax is doubt- fully regarded either as produced by Htyrax offi- cinale or by a species of liquidambar (q.v.). It seems probable that there are two kinds. STO'RER, D.A.VID HrMPHREYS (1804-91). An American physician and naturalist. He was born in Portland, Me., and graduated at Bowdoin in 1822. After studying medicine he settled in the practice of his profession in Boston and continued there until his death. In 1S54 he was called to the chair of obstetrics and medical jurisprudence in the Harvard Medi- cal School. Storer was for many years as- sociated with Louis Agassiz in his studies of zoiilogy and herpetology. He published: Report on the Ichthyology and Herpetology of Massa- chusetts (1839) ; Synopsis of the Fishes of North America (1846) ; and a History of the Fishes of Massachusetts (1853-67). STO'REY, MooRFiELD (1845—). An American lawyer, born in Eoxbury, Mass. He graduated at Harvard in 1866, studied at the Harvard Law School, and in 1869 was admitted to the bar. In 1867-69 he was private secretary to Senator Charles Sumner, and in the latter year began the practice of his profession in Boston. An Independent in polities, he was prominent in the "Mugwump' movement of 1884, and after the Spanish War became an ardent Anti-Imperialist and was defeated for Congress in 1900. He pub- lished the Life of Charles Sumner (1900) in "American Statesmen Series." STORK (AS. store, OHG. storah, Ger. Starch, stork; connected with Gk. rdpyoc, torgos, vul- ture). The popular name for a family of birds, the Ciconiid!P, allied to the herons and ibises. They are large birds, with long legs, half-webbed toes; the bill longer than the head, straight, strong, pointed, and without any groove; the nostrils pierced longitudinally in the horny sub- stance; the eyes surrovmded by naked skin. The species are about twenty-five in number and are of very wide geographic distribution. The common