Lighting and Artificial Illumination

In the United States there were several pioneer arc light sys tems. The earliest were those of William Wallace, of Ansonia, Conn., who became associated with Prof. Moses G. Farmer; Edward Weston, of Newark, N.J. ; Charles F. Brush, of Cleveland, 0., and Prof. Elihu Thomson, who became associated with Edwin J. Houston. Brush announced his first arc lamp in 1877 and in a few years Brush arc lights were all over the world. Early in 1879 the first Thomson-Houston arc dynamo was built in Phila delphia. In the United States also four men attacked the problem of producing incandescent lamps popularly named "sub-dividing the electric light." These were: William E. Sawyer, Prof. Moses G. Farmer, Hiram S. Maxim and Thomas A. Edison. Sawyer be came associated with Albon Man, his patent attorney. The Sawyer-Man Electric Company developed several lamps con sisting of a piece of graphite, operating in nitrogen, covered by a glass globe cemented to a metal holder. The lamps were designed so that they could be renewed by opening the joint and putting in a fresh burner. Farmer made a lamp consisting of a graphite rod which also operated in nitrogen gas. Maxim made two lamps. One consisted of a piece of sheet platinum operating in air and the other of a graphite rod operating in a rarefied hydro-carbon vapour.

Edison gave his famous display of a complete incandescent lighting system late in Dec. 1879 at Menlo Park. As far back as 1838, Prof. Jobard, of Brussels, suggested that a small piece of carbon incandesced in a vacuum by electricity, might be em ployed as a lamp. Edison, on account of his work on his telephone receiver, was eminently qualified to experiment with carbon for lamps. He estimated that the carbon should be not over in in diameter, or about the size of ordinary heavy sewing thread. Then he saw the possibility of carbonizing a piece of sewing thread by heating it in an air-tight crucible. There has been some misconception of exactly what Edison did invent. He was not the first man to make an incandescent lamp, as indicated in the f ore going summary. He concluded, however, that such lamps must be connected to the circuit in multiple so each one would be independent of the others. He also realized that lamps connected in multiple must be of high resistance, and he named this high resistance carbon burner a "filament." Finally he realized that continuous high vacuum was essential and produced it by making the glass container closed at all points by fusion of the glass.

Edison's basic lamp patent No. 223,898, which the courts upheld as covering the modern incandescent lamp, covered (1) a high resistance filament of carbon, in (2) a chamber made entirely of glass and closed at all points by fusion of the glass, which con tained (3) a high vacuum and through which (4) platinum wires passed to carry current to the filament. It was a patent on a combination of old elements which produced a new thing—a lamp suitable for multiple distribution over large areas. The first commercial installation of the lamp was made on the steamship "Columbia" of the Oregon Railway and Navigation Company. The original installation of about 180 lamps ran for 15 years. During the two years, 1881-82, over 150 other installations were made, aggregating over 30,000 lamps. These installations included steam ships, machine and car shops, mills, stores, offices, theatres, hotels, residences, etc. ; all of them were entirely successful.

The enclosed arc was patented in 1894 by L. B. Marks and for about ten years was the favourite unit for high candle-power electric lighting in America. Five years later came the Bremer flame arc lamp, which was followed by other types of lamps using special electrodes, designed to increase the luminous efficiency and intensity. The best known of all, the luminous arc, or the magnetite, developed in 1900, was largely due to Steinmetz. The electrodes are composed of metals and metallic oxides, without any carbon "body." The magnetite is essentially a direct-current lamp. Arons in 1892 originated the mercury-vapour arc, although it was not used as an illuminant until April 1901, when Peter Cooper Hewitt displayed his mercury-vapour lamp before the American Institute of Electrical Engineers. The first practical installation was made in the composing room of the New York Evening Post in 1903. Dr. Nernst in 1899 produced commercially a new form of incandescent lamp which during the first decade of the present century made considerable headway in the lighting field. The filament of the Nernst lamp was a solid electrolyte composed principally of rare earth oxides.

Improvements on the manufacture and construction of the carbon lamp proceeded from the time of its first successful use.

The filaments instead of being bolted or clamped were pasted to the leading-in wires. The "squirted cellulose" replaced bamboo for the carbon filament. The turn-down lamp made it possible to conserve energy when the full light value of the lamp was not needed. Evidence of a tendency toward a complete displacement of the cellulose filament by a metal filament was given in the appearance of Dr. Welsbach's osmium lamp in 1898. Then in 1905 the "Gem," a metallized carbon filament lamp, appeared in America. The first tantalum laboratory lamp was made by on Bolton and Feuerlein in 1901. It was placed on the market in 1906 but soon disappeared due to the advent of the nigher efficiency tungsten filament lamps. The pressed filament tungsten lamp (1907) was the invention of Alexander Just and Franz Hanaman of Vienna. The filament was very fragile. From it in 1910 was evolved the drawn wire tungsten lamp, developed by Dr. William D. Coolidge; this filament has proved strong, durable and cheap. Improvements in this lamp have resulted in obtaining high efficiencies. The gas-filled lamp developed in 1913 by Dr. Irving Langmuir, an associate of Dr. Coolidge in the research laboratories of the General Electric Company, has an efficiency many times that of the old carbon lamp.

The efficiency of the early carbon lamp produced in 1879 was about 1.4 lumens per watt. In 188o the carbonized bamboo fila ment had an efficiency of 1.6 lumens per watt; the squirted cellulose filament introduced in 1886 2.5 lumens per watt; the treated cellulose filament of 1896 about 3.3 lumens per watt and the metallized carbon filament of 1905 4 lumens per watt. The tantalum filament lamp, commercially introduced in 1906, gave 5 lumens per watt, while the first tungsten lamp sold had an efficiency of 8 lumens per watt, or double that of the best type of carbon lamp. Modern tungsten filament lamps operate at efficiencies ranging from 8 lumens per watt for the small sizes up to 3o lumens per watt for the higher wattage types.