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INDUSTRIAL A X D E;L’GIAVEERING CHEMISTRY
Vol. 18, Xo. 9
A Half-Century of Artificial Lighting’ By M. Luckieshz NATIONAL LAMPWORK5
OF
GENERAL ELECTRIC Co , NELAPARK,CLEVELAND, OHIO
H E past fifty years have witnessed practically all the development which has taken place in electric lighting. A half-century ago only a few factories were using arc lamps, although they had been installed to some extent in lighthouses for a number of years. The first industrial installation of arc lamps was made in Paris in 1873 and by 1876 they were in use in a number of factories in France. I n 1878 some streets in Paris, notably the Avenue de l’opera, were lighted by arcs, this being the first street lighting by electricity. Previously many types of arc lamps had been invented, but progress had been seriously handicapped by lack of suitable mechanical generators of electricity. I n 1876 homes were lighted by candles, kerosene lamp?, and flat-flame gas jets. Two years later it was reported in the newspapers that Edison had succeeded in inventing an incandescent lamp and “subdividing” the current so that every householder could have electric light where and when it was wanted. This was a problem which had been attacked by other inventors, but without success. Up to that time gas had been used principally for lighting, and these reports had the effect of seriously depressing the market value of gas company stocks. The reports were premature, however, for the carbon incandescent lamp was not a practical success until three years later. By this time many had become skeptical as to the practicability of an electric filament lamp. It is interesting to read the comments of scientists of that day who were, or later became, famous. For example, Sylvanus P. Thompson is quoted in the Electrical World, September 9, 1922, as having made the following statement about the time of Edison’s invention:
T
I think that any system of electric lighting depending on incandescence will utterly fail from an economic point of view and will be the more uneconomic the more the light is subdivided.
Hyppolyte Fontaine, in an article in the Revue Zndustrielle, in 1878 discussed Edison’s carbon-filament lamp as compared with earlier inventions and ended his discussion thus : Now, if anyone wishes to know what we think of this affair, we will tell him that the journalistic scribes have no object beyond that of preparing for the creation of a company with a fabulous capital, which company will never, to the end of eternity, pay a dividend to its shareholders.
Fifty years ago not a single home was wired for electricity and only a few factories were wired. At the beginning of 1926 more than 50 per cent of the homes in the United States were wired for electrical service, and these constitute about 75 per cent of all homes within easy reach of centralstation service. The average present wattage of all lamps in the sockets of the average home is nearly one kilowatt. Industry in the United States is a t present approximately 65 per cent electrified. Last year there were sold in the United States 278,600,000 large incandescent lamps, 123,000,000 automobile lamps, 30,000,000 flash-light lamps, and 43,000,000 Christmas tree lamps, a total of nearly half a billion lamps of all sizes. I n 1876 gas lighting had not reached its peak of development, for the Welsbach mantle was not invented until a decade later. It gave a new impetus to gas lighting and 1 Received
May 29, 1926. Illuminating Engineering Society; Director, Lighting Research Laboratory.
* President,
prolonged its period of competition with electric lighting for many years. With the introduction of the drawn-wire tungsten lamp in 1010, and the gas-filled tungsten lamp in 1914, gas lighting has been rapidly superseded by electricity. In 1876 practical lighting by electric arc lamps was also in its infancy. As previously stated, the electric arc had been installed in some factories, but its successful application probably dates from the introduction of the Jablockoff “electric candle” just a half-century ago. This was also an electric arc employing carbons, but differed from others in that it required no adjusting mechanism. The two carbons were maintained vertically, side by side, with a thin insulator such as porcelain between them. As the carbons burned away the insulator melted a t the same rate, thus keeping the arc constant in length. This system found successful commercial application for several years. Varieties of Electric Lamps
During the past fifty years many ingenious incandescent and arc lamps have been introduced. Those which attained some degree of commercial application included the open and enclosed carbon arcs, the magnetite arc, and the mercury arc. Incandescent filament lamps have included carbon, osmium, metallized carbon, tantalum, Nernst, and vacuum and gas-filled tungsten lamps. The carbon and metallized carbon filament lamps have had the greatest period of usefulness, as they did not have serious competition for about thirty years. Since the introduction of the more efficient tungsten lamps the use of carbon lamps has declined, until now relatively few are used. The low-pressure discharge tube a t one time appeared promising and some large installations were made. But these have disappeared and this type of light source is now confined to very small units that are more or less markers, with the exception of some uses in display lighting. Recent developments seem destined to return it to certain specialized fields, since it can now be made in units consuming less than one watt. During these fifty years the arc lamp has received a great deal of attention and attained a high degree of usefulness, particularly for street lighting. However, even in this field it is gradually being displaced by high-intensity tungsten filament lamps. It will probably remain preeminent in the searchlight field for some time, inaemuch as the high intensity available in a very concentrated light source makes it possible to obtain enormous beam candlepowers. The mercury arc is used to some extent in the industries. From the time of its introduction early in the past halfcentury, the incandescent filament lamp has been improved by leaps and bounds, until finally it has far outstripped other electric light sources for general lighting purposes. I n a brief comparison of artificial lighting in 1926 with that in 1876 we may confine our considerations to the electric filament lamp of the present time and the feeble gas flames of fifty years ago. One outstanding difference between the present and the past is the extreme controllability of light from filament lamps as compared with very little control over the light from flames. The electric filament has won in this fifty-year battle owing to (1)its divisibility into almost any desired size; (2) the possibility of shaping the filament so that advantage can be taken of optical principles in the
design of lighting cqiiipmciit; ( 3 ) tlin e n t h u r o the filament Ixilh which makes it possible to operate the light source wiili safety almost, aisywlrcrc; (4) the relatively great progrcss in the c&icncy of light production; and ( 5 ) the light soiircc as compared with the ie arc Lanip, lo\v-presmrc discharge Luminous Efficiency
US intawst to notc hore tlic a~)proxiinnteluminous nnd filament t.emperatiires of some clear-bulb vacuum lamps of one of the most commonly used wattages: i~
T y p e O i lamp Sidisun'r early Fars>o,,ia,,,ps '&watt
lnoilern rrriron
io-,vatt gem
50-wilti tantal",,, ao-watt LUliXStPn (gls-fiiied)
Pilament fcmpeiatiire 1840 18115 1885 242.5
Ap,,*ox. lumens per watt
1. a
5.3 4.n
4.9 11.1
Tire Inmetis per watt of some filament l a m p is more tharr twice the highest value in this table. The average lumens per watt of all lamps sold in 1907 was 3.5. I n 1925 the merage was 12.5 lumens per watt.
to piy his till for lighting. This great difference is duo to tllc diffimnc,e in crwt of prodrreing light, sixice tho 1926 laborer receives apj~roximat,ely83.22 per day as COISSpared with 91.43 fifty years ago. At tlie present tinre the average family is spending sewn writs per day for electric light in the honle. On the same basis of comparison, if the 1876 laborer had used tallow candles he would have been alile to buy nothing but light, and would have had to labor aimoat twenty-four liours pcr day to pay for that. Tlic nverage luminous elficieiicy of all filament lamps which will tic sold in the irriitcd Statcs in 1926 will be approximately ten times that of the early carlion lamps. This great, inwrase in hnninous efficiency is rcsponsiMe for a large part oi tlie decrease in cost of light. during this period, ani1 this rlecreasc in cost has greatly increased t.he amount of light used. However, the intensities of artificial illusnination commonly encountered today are still far below what is known to be best for vision and economy iiigeiicral, and orrly a very small fract,ion of tlie average intensity of illurniiiatiolr under wliich the eyes evolved outdoors. Another effect of the inereased eiliciency of light production is the possibility of sacrificing some energy to ohtaiii a more desirable color or quality of light. The gas flames and carbon lamp? gave light whi& was very yellow, differing greatly in spectral character from that of dayiight. Now it is possible to obtain lamps in blue-green bulbs whioh give light approximating daylight. in color. If a very accurate reproduction of daylight is desired, as in color discrimination, it may be obtained by the use of colored glass accessories and gas-filled tungsten lamps. If we wish to revert to the warmer tints of the candle flame or the fireplace, superficially coated lamps producing the are availahle. Hence we see that we c and quality of light a t loai cost. Economic Effects of Illumination
l l i e cost of light today from tungsten filament lamps is only a sinal1 fraction of tlic cost fifty years ago. If the unskilled labnrer of a half-cent.ury ago ha,d used as much light as is now used daily in tlie average American home, he would have had to work two and one-half hours daily to pay his gas-lighting bill alone, as compared with approximately ten minutes daily for tlie average unskilled laborer in 1926
Artificial light turns night into day. We can now see the time ahead when there is the possibility of a 24hour industrial day. We have long had the 24-hour day on the railrnads, but it has not yet come generally in our offices and factories. A two-shift day is now in use in many factories, and helps materially to reduce costs of production by spreading the overliead o ~ e greater r production. Many tests have been made to determine the effect of illumination upon production. Practically without exception they have shown that a considerable increase in proriuctioii has rcsulted from increased illumination. I n every case the value of the increased production ha3 far exceded the increase in cost of the light furnished. Fifteen years ago factory and officeillumination intensities of three or four foot-candles represented the best practice, but intensities of ten to twenty foot-candles are now in common use. On the tiasis of t.ests already made it has becn estimated that if all factories and offices in the United States were brought up to an average illumination of twenty foot-candles or more, the net econondo gain would be sufficient to pay off our war debt in one year. Good lighting also decreases spoilage of materials, decreases accidents, conserves eyesight, and makes us healthier and happier. Whereas there was lit.tle or no illuminat.ion of streets fifty years ago, most of our important street,s are now illuminated and the lighting is being steadily improved. Our preseiit, white ways were not economically possible a halfcentury ago. In our homes we can have eontmllahle light in every room, not only for ultilitarisn purposes but for the charm and decorative value of light,. Fifty years ago light in the theater was principally used t.o revcal the action on the stage, but now in many cases the lighting effects furnish
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
a large part of the entertainment. Both the production and projection of motion pictures are dependent on our modern electric illuminants. Altogether, we owe a great deal of our
Vol. 18, KO.9
progress to the improvements in electrical illumination during the past fifty years. It is constantly contributing to our prosperity, progress, safety, comfort, and happiness.
Fifty Years’ Progress in Aluminum’ By Junius David Edwards ALUMINUM COMPANYOF AMERICA, NEWKENSINGTON, PA.
I
N LOOKIKG back fifty years to the date of the founding
of the AXERICANCHE~V~ICAL SOCIETY,we are struck by the fact that, practically speaking, the aluminum industry did not then exist; it has reached its present state of development within the lifetime of the SOCIETY. I n contradistinction to the other common metals, aluminum can only be produced by methods involving chemical and electrochemical discoveries and technic, and these are the reasons why it remained totally unknown to the human race until the early part of the last century. While its progress has been rapid in many ways, it nevertheless has made but a beginning, and the future is one of great promise. Aluminum is the only common metal whose ores require an extensive and exhaustive chemical refining treatment to produce a chemically pure compound before its reduction to metal. Every other material consumed in its reduction must also be of the highest purity. The production of aluminum is particularly dependent, therefore, on chemical manufacturing and control processes. Men of an earlier age could and did produce iron, copper, gold, silver, lead, and tin by rule-of-thumb processes, but only the development of modern science makes possible the production of aluminum. Preparation First made by the Danish chemist and physicist, Oersted, in 1825, its early history was one of purely chemical development. The names of Wohler and Deville are closely associated with the production of aluminum by the reduction of aluminum fluoride and cryolite with metallic sodium. I n an effort to cheapen the production of aluminum, Castner discovered and developed his process for the production of sodium. Although the price of aluminum fell to about seven dollars a pound, this did not prove to be the solution of the problem. It remained for Charles M. Hall, an American chemist just out of college, to discover, early in 1886, the electrolytic process of reduction which marked the birth of an industry. The story of Hall’s persistent and successful fearch for a practical method of producing aluminum has already been told. I n France, and at almost the same time, P. V. Heroult discovered substantially the same process as did Hall. The United States Patent Office, however, awarded priority of invention to Hall. The preparation of a pure oxide of aluminum from the naturally occurring crude hydrate, bauxite, was worked out by Bayer. I n spite of the great variety of processes which have been studied and proposed by inventors in every land, substantially all of the aluminum oxide consumed by the industry is still prepared from bauxite by a chemical process involving the production of sodium aluminate (either by digesting bauxite with caustic soda or fusing it with soda ash) and its decomposition (by hydrolysis or precipitation with carbon dioxide) to form the pure hydrate, which is converted to the oxide by calcination. The numerous processes for extracting the oxide from clay, usually by digestion with acids, followed by purification and de1 Received May 27, 1926.
composition of the salts, seem to be inherently unable to compete with the Bayer process except under very exceptional conditions. The electric furnace processes for refining bauxite have not been a commercial factor up to this time, but seem to have important possibilities of future development. The preparation of purified alumina is in itself an immense chemical industry. The estimated production of 300 million pounds of aluminum in 1925 required the preparation of more than 600 million pounds of purified alumina. One works alone in the United States produces over 400 million pounds of alumina annually with a n average impurity content of only about 0.5 per cent, of which less than 0.1 per cent (silica and iron oxide) is reduced and appears in the metal. The early years of the aluminum industry were largely occupied in solving the technical and engineering problems incident to establishing the electrolytic process on a commercial scale. To the versatile genius of Charles M. Hall, aided by the enthusiastic support of his associate, Alfred E. Hunt, is due much of the credit for this development. Many inventions, some patented but most of them not, were Hall’s contribution to the art. His faith in the future of aluminum was such that he confidently urged continued expansion, even though no immediate market for the metal was in sight. I n recognition of his achievements Hall was presented with the Perkin Medal by the Society of Chemical Industry in conjunction with the AMERICANCHEMICAL SOCIETY and the American Electrochemical Society in 1911. When hydroelectric power became available in quantity a t Niagara Falls, the aluminum industry of this country moved there. However, with the constantly increasing demand for power, in and around our large cities, the center of production has moved to lower cost water-power cites. The latest of these developments is the establishment of new works on the Saguenay River, Province of Quebec, Canada, where there is a potential 800,000 horsepower waiting to produce aluminum. Uses
Having learned how to make aluminum, there still remained the formidable problem df finding a stable market. For many years practically every use of aluminum was a new use. The producer was frequently forced into a manufacturing business in order to prove that aluminum could be satisfactorily employed for this purpose or that. Fabricating methods had to be devised or adapted, and the industry still finds it has countless problems to solve in the melting, casting, rolling, drawing, spinning, extruding, forging,,pressing, machining, welding, soldering, and finishing of aluminum and its alloys. The aluminum cooking utensil formed one of the first and best known outlets for aluminum. Singularly, one of the latest uses has been its extensive employment in electric household devices, such as the vacuum cleaner and washing machine. Through the vision and inventive ability of William Hoopes the practicality of aluminum conductors for electric power
