Note on the distribution of energy in the visible spectrum of a cylindrical acetylene flame

Note on the distribution of energy in the visible spectrum of a cylindrical acetylene flame

NOTES FROM NELA RESEARCH LABORATORY.* N O T E ON T H E D I S T R I B U T I O N OF E N E R G Y IN T H E V I S I B L E S P E C T R U M OF A C Y L I...

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NOTES

FROM

NELA

RESEARCH

LABORATORY.*

N O T E ON T H E D I S T R I B U T I O N OF E N E R G Y IN T H E V I S I B L E S P E C T R U M OF A C Y L I N D R I C A L A C E T Y L E N E F L A M E . By Edw. P. Hyde, W. E. Forsythe and F. E. Cady.

*3t KNOVv'LEDGEOf the distribution of energy in the visible spectrum of an acetylene flame has become important within the last few years through the use of this flame, in cylindrical form, in investigations of the visibility of radiation. It can be shown by computation that the data on acetylene published by Coblentz form a curve in the visib!e spectrum which will not agree with that of a black body at any temperature to better than 7 or 8 per cent. As this would mean that no color-match could be obtained and as previous experience of the authors had led to the conclusion that the energy curve of acetylene differed in shape from that of a black body only in the extreme red, a short investigation was undertaken to verify this conclusion. Tungsten lamps whose current color-temperature relation was carefully determined in this laboratory were sent to the Eastman Kodak Company and to the Bureau of Standards with the request that they be compared with the acetylene flame and the current for color match be found. The results gave an average value of 236o: K. ± IO ° K., and neither laboratory reported any difficulty in obtaining a match in color. However, the Bureau of Standards reported a difference amounting to about 75° K. between the flame as given by the Eastman standard burner and that given by the " Crescent Aero burner, the latter being higher. The spectral distribution of the flame was measured by means of a speetrophotometer and a spectral-pyrometer and the results gave a curve agreeing within the limits of error with that of a black body at 236o ° K. In the extreme red, beyond o.7o/, there was indication of a higher emissivity for the acetylene. A photographic method gave results corroborating those just mentioned. A test of the sensibility of the color match method to show differences in the spectral energy curve, showed that if two spectral curves matched at o.5/. and o.7/. and differed by as little as "

* Communicated by the Director. 122C/

I30

NELA RESEARCH LABORATORY NOTES.

[J. F. I.

4 per cent. in the middle of the spectrum, the two light sources could not be made to match in color. In conclusion, it is recommended that the relative emission intensities of a cylindrical acetylene flame, at least for that type represented specifically by the Eastman standard burner and for the wave-length interval from o.4~ to o.7~, should be taken as identical with those of a Mack body at 236o ° K. CLEVELAND,OHIO,June, 1919.

American Peat Industry. A~ON. (U. S. Geological Survey Press Bulletin, June, 1919. )--The output of crude peat in the United States in 1918 far exceeded that of any preceding year and the general increase, which was stimulated by the war, was shared by practically all branches of the industry. Though extensively used as fuel in Europe and widely known in the United States as a potential source of heat and power, peat has been unable in most parts of the country to compete with coal and many peat operators have therefore directed their attention to the utilization of peat in agriculture with gratifying results. Use of Peat in .4griculture.--Peat fertilizer was first marketed in commercial quantities in 19o8, and stock-food peat in 1912, and though there is still some prejudice against the use of these products the agricultural branch of the peat industry has been successful and the quantity of fertilizer and stock-food peat annually produced is increasing. Large quantities of these products were made in 1918, but the most striking development of the year was the production of more peat fuel in the New England States than has been manufactured commercially in the entire United States in all preceding years. Almost equally striking was the widespread interest manifested in our peat resources which had heretofore been generally regarded as of doubtful value. Large quantities of peat or sphagnum moss were produced and utilized in this country in 1918 for stable litter, packing material, and surgical .dressing, and several hundred thousand acres of peat soils were used for the growth of both general and truck crops. The peat litter was produced by the owners of small bogs for their own use, but the packing material was sold to florists for $25 a ton. According to J. W. Hotson, of the American Red Cross, more than half a million peat moss p~ds were prepared in this country from October, 1917, to November II, 1918, by the Northwest and Atlantic divisions of that organization. Most of the moss was gathered by volunteer labor from bogs in Washington, Oregon, and Maine, and the pads were used in American military hospitals, both at home and abroad. The quantity of crude peat produced in the United States in 1918 "was 151,521 short tons. The total number of p|ants at which peat was commercially produced was 25 .