The most important development of the storage battery was made by Camille A. Faure, in 1880 (U. S. Pat. No. 252,002, Jan 3, 1882). In the early part of 1881 there was sent from Paris to Glasgow a so-called “box of electric energy” for inspection and test by Sir William Thomson, the eminent electrician. It was one of the first storage batteries of M. Faure. The illustration, Fig. 66, shows a battery of this type in which the lead plates covered with red lead (Pb₃O₄) replace the plain lead plates in the Planté cell. The action of the battery is that when a current of electricity is passed into the same, the red lead on one plate (the negative) is reduced to metallic lead, and that on the other is oxidized to a state of peroxide (PbO₂). These actions are reversed when the charged cell is discharging itself. The elements of this battery consist of alternate layers of sheet lead, and a paste of red oxide of lead. These are immersed in a 10 per cent. solution of sulphuric acid in water. Many minor improvements have been made in the storage battery, covered by 716 United States patents, most of which relate to cellular construction for holding the mass of red lead in place. The most notable are those of Brush, to whom many patents were granted in 1882 and 1883. [Illustration: FIG. 66.--STORAGE BATTERY--FAURE TYPE.] The storage battery finds many important applications. For furnishing current for the propulsion of electric street cars it has proved a disappointment, on account of the vibrations to which it is subjected, and the great weight of the lead, which in batteries of suitable capacity runs up into many thousands of pounds. The storage battery finds a useful place, however, for equalizing the load in lighting and power stations, and is there brought into action to supplement the engine and dynamo during those hours of the day when the tax or load is greatest. It is also used to keep up electrical pressure at the ends of long transmission lines; for telegraphing purposes; for isolated electric lighting; for boat propulsion; the propulsion of automobile carriages; and in all cases where a portable source of electric current would find application. The great growth of automobile carriages in the past year has greatly stimulated the output of storage batteries. One large company (The Electric Storage Battery Company), manufactured and sold storage batteries for the year ending June 1, 1899, to the amount of $2,387,049.91, and there are many other manufacturers. [Illustration: FIG. 67.--ELECTRIC WELDING.]