ABNEY et FESTING. - Atmospheric absorption in the infra-red of the solar spectrum (Absorption atmosphérique de la partie infra-rouge du spectre solaire); Proceedings of the Royal Society, vol. XXXV, p. 80; 1883

1884 ◽  
Vol 3 (1) ◽  
pp. 219-219
Author(s):  
G. Foussereau
Keyword(s):  
Royal Society ◽  
Solar Spectrum ◽  
Atmospheric Absorption ◽  
Infra Red

scholarly journals VII. The influence of water in the atmosphere on the solar spectrum and solar temperature

1883 ◽  
Vol 35 (224-226) ◽  
pp. 328-341 ◽  
Keyword(s):  
Solar Spectrum ◽  
Absorption Bands ◽  
Atmospheric Absorption ◽  
Infra Red ◽  
Influence Of Water

In our paper on “Atmospheric Absorption in the Infra-red of the* Solar Spectrum” (“Proc. Roy. Soc.,” vol. 35, p. 80), we stated that the absorption by water coincided with the absorption bands to be found in the solar spectrum, and our proof rested in photographs which had been taken for some time back. In the diagram which we published (and in which are slight errors in shading at some parts, and which we here correct) we showed the coincidences as far as λ10,000, that being the limit to which we could accurately fix the wave-lengths.

scholarly journals II. On the atmospheric lines of the solar spectrum, illustrated by a map drawn on the same scale as that adopted by Kirchhoff

1875 ◽  
Vol 23 (156-163) ◽  
pp. 201-202
Keyword(s):  
Sea Level ◽  
Royal Society ◽  
Solar Spectrum ◽  
The Sun ◽  
Atmospheric Absorption ◽  
Spectroscopic Observations ◽  
Clear Atmosphere

The spectroscopic observations described in this paper were made with instruments belonging to the Royal Society, and in accordance with certain suggestions which had been made to the author by a committee appointed in consequence of a letter of his to Sir Edward Sabine, President, dated 13th February, 1866. In view of his residence at a considerable height above the sea-level, and of the exceedingly clear atmosphere prevailing at some periods of the year, it was suggested that the locality was peculiarly favourable for a determination of the lines of the solar spectrum due to atmospheric absorption, and that, for this purpose, the solar spectrum when the sun was high should be compared with the spectrum at sunset, and any additional lines which might appear in the latter case should be noted with reference to Kirchhoff’s map. Accordingly the author set to work with the spectroscope first supplied to him, and in the autumns of 1868 and 1869 mapped the differences in question from the extreme red to D. These results appeared in the 'Proceedings of the Royal Society' for June 16,1870, and the map of the spectra, sun high and sun low, of the region in question forms plate 1 of the 19th volume.

scholarly journals II. Atmospheric absorption in the infra-red of the solar spectrum

1883 ◽  
Vol 35 (224-226) ◽  
pp. 80-83 ◽  
Keyword(s):  
Prolonged Exposure ◽  
Solar Spectrum ◽  
Degree Of Saturation ◽  
Atmospheric Conditions ◽  
Absorption Bands ◽  
Atmospheric Absorption ◽  
Easterly Wind ◽  
Infra Red ◽  
The Difference ◽  
Hot Weather

Any investigations on the subject of atmospheric absorption are of such importance in the study of meteorology, that we have deemed it advisable to present a preliminary notice of certain results obtained by us, without waiting to present a more detailed account which will be communicated at a future date. From 1874, when one of us commenced photographing the spectrum in the above region, till more than a year ago, the extremely various manners in which the absorptions took place caused considerable perplexity as to their origin, and it was only after we had completed our paper on the absorption of certain liquids, that a clue to the phenomena was apparently found. Since that time we have carefully watched the spectrum in relation to atmospheric moisture, and we think that more than a year’s observations in London, when taken in connexion with a month’s work, at an altitude of 8,500 feet on the Riffel, justify the conclusions we now lay before the Society. A study of the map of the infra-red region of the solar spectrum, and more especially a new and much more complete one, which is being prepared for presentation to the Royal Society by one of us, shows that the spectrum in this part is traversed by absorption lines of varying intensity. Besides these linear absorptions, photographs taken on days of different atmospheric conditions, show banded absorptions superposed over them. These latter are step by step absorptions increasing in intensity as they approach the limit of the spectrum at the least refrangible end. In the annexed diagram, fig. 4 shows the general appearance of this region up to λ 10,000 on a fairly dry day : the banded absorption is small, taking, place principally between λ 9420 and λ 9800 : a trace of absorption is also visible between λ 8330 and λ 9420. On a cold day, with a north-easterly wind blowing, and also at a high altitude on a dry day, these absorptions nearly if not quite disappear. If we examine photographs taken when the air is nearly saturated with moisture (in some form or another) we have a spectrum like fig. 1. Except with very prolonged exposure no trace of a spectrum below λ 8330 can be photographed. Fig. 2 shows the absorption bands, where there is a difference of about 3° between the wet and dry bulb, the latter standing at about 50°. It will be noticed that the spectrum extends to the limit of about λ 9420, when total absorption steps in and blocks out the rest of the spectrum. Fig. 3 shows the spectrum where the difference between the wet and the dry bulb is about 6°. Figs. 5 and 6 show the absorption of thicknesses of 1 foot and 3 inches of water respectively, where the source of light gives a continuous spectrum ; ⅛ inch water merely shows the absorption bands below 9420. It will be seen that there is an accurate coincidence between these “ water bands” and the absorption bands seen in the solar spectrum, and hence we cannot but assume that there is a connexion one with the other. In fact, on a dry day it is only necessary to place varying thicknesses of water before the slit of the spectroscope and to photograph the solar spectrum through them, in order to reproduce the phenomena observed on days in which there is more or less moisture present in the atmosphere. It is quite easy to deduce the moisture present in atmosphere at certain temperatures by a study of the photographs. There does appear a difference, however, in the intensity of the banded absorptions in hot weather and in cold about up to 50°. In the former they are less marked when the degree of saturation and the length of atmosphere traversed are the same as in the latter.

scholarly journals II. The wave-lengths of A, a , and of prominent lines in the infra-red of the solar spectrum

1883 ◽  
Vol 36 (228-231) ◽  
pp. 137-138
Keyword(s):  
Solar Spectrum ◽  
Ultra Violet ◽  
Infra Red

M. Fievez has recently sent me a map of the solar spectrum from C to A* inclusive, and as part of this region is one which I have been measuring, I have examined the new publication with great interest. Photography and eye measurements do not exactly coincide in the detail of the grouping of the little a group as far as A, and A itself is shown by M. Fievez’s map as wanting some details which appear in the photographs. Thus in the photographs there are some seventeen lines, whilst in M. Fievez’s map there are but thirteen. Between A and a there are several lines of marked intensity in the photograph which are not shown in the new map. The wave-lengths of the different lines from above “ a ” to A are not the same as those given by Fievez, when they are taken from comparison photo-graphs of the 1st order of the red and 2nd of the ultra-violet on the same plate, or when checked by photographs of the 2nd order of the red with the 3rd order of the green taken in a similar manner. In my paper, “Phil. Trans.,” Part II, 1880, I gave a method of using mirrors by which this could be effected, but since Professor Rowland introduced his concave gratings this is much more readily carried out. He has kindly furnished me with gratings for the purpose, having about 14,400 lines to the inch, with focal distances of 7 feet 6 inches and 12 feet 6 inches respectively. These have been employed in determining the wave-lengths of this part of the spectrum. Cornu’s map was used as a reference for the ultra-violet wave-lengths, and Ångström’s map for those in the blue and green. The two maps may be taken as equally exact. The determination of A has been made by Maseart, Smyth, and others, besides Ångström and Langley, with discordant results. I think the above may be taken as accurate as are Cornu’s and Ångström maps.

scholarly journals VI. Corrections to the computed lengths of waves of light published in the Philosophical Transactions of the year 1868

1872 ◽  
Vol 162 ◽  
pp. 89-109
Keyword(s):  
Spectral Line ◽  
Royal Society ◽  
Wave Length ◽  
Solar Spectrum ◽  
Spectral Lines ◽  
Fifth Order ◽  
Principal Lines ◽  
General Table

In a paper communicated to the Royal Society in the year 1867, and printed in the Philosophical Transactions for 1868, I attempted the computation of the Lengths of Waves of Light for all the lines which Kirchhoff had observed in the Solar Spectrum, by adopting an algebraical formula of the fifth order, and substituting in it for every spectral line the value of Kirchhoff’s measure for that line, the numerical bases of the formula being derived from Fraunhofer’s and Ditscheiner’s measures of the wave-lengths for six principal lines. Subsequently I obtained the means of comparing many of my computed results with measures of wave-lengths by Ångstrȍm and Ditscheiner, and l found that the discordances were far larger than I had anticipated. I remarked, however, “By means of the comparison........ there is no difficulty in computing for any other line the correction that ought to be applied to the wave-length in the principal Tables, in order to exhibit the true wave-lengths on Ditscheiner’s scale, without appreciable error.” Want of leisure long prevented me from entering upon the examination necessary for preparing, in a form easy for applications, the correction which my numbers required. Lately, however, I have taken it up; and I have constructed a Table of corrections to the numbers of my Table generally, and I have applied them, both to the general Table of wave-lengths and to the values of wave-lengths for the spectral lines of the atmosphere and several metals (the accurate exhibition of which was, in fact, the first object of my computations). I now offer these corrections and corrected numbers for the acceptance of the Royal Society.

scholarly journals The preparation of eye-preserving glass for spectacles

1914 ◽  
Vol 214 (509-522) ◽  
pp. 1-25 ◽  
Keyword(s):  
Royal Society ◽  
Molten Glass ◽  
Ultra Violet ◽  
Metallic Oxides ◽  
Infra Red ◽  
Glass Plates ◽  
Glass Workers ◽  
The Invisible

Since March, 1909--in connection with the Glass Workers' Cataract Committee of the Royal Society--I have been experimenting on the effect of adding various metallic oxides to the constituents of glass in order to cut off the invisible rays at the ultra-violet and the infra-red ends of the spectrum. The work has been done chiefly in my own laboratory. I have been aided by Mr. Harry Powell, of the Whitefriars Glass Works, who prepared several pots of coloured glass from my formulae on a much larger scale than could be made outside a glass works. From these glasses cylinders and sheets were made. The main object of this research is to prepare a glass which will cut off those rays from highly heated molten glass, which damage the eyes of workmen, without obscuring too much light or materially affecting the colours of objects seen through the glass when fashioned into spectacles, but the work necessitated an examination of the screening properties of glass plates for ultra-violet and luminous light, and therefore the research was enlarged so as to embrace the three forms of radiation.

scholarly journals XIX. On the photographic arc spectrum of iron meteorites

1894 ◽  
Vol 185 ◽  
pp. 1023-1028
Keyword(s):  
Royal Society ◽  
Solar Spectrum ◽  
British Museum ◽  
Iron Meteorites ◽  
Electrolytic Iron ◽  
Comparison Spectrum ◽  
Size And Shape ◽  
Previous Communication ◽  
Oxyhydrogen Flame ◽  
Made In

In a communication to the Royal Society in 1887, I gave an account of certain experiments which I had made in connection with the spectra of various meteorites at various temperatures. The spectra were observed at the temperature of the oxyhydrogen flame and the electric spark without jar, and when glowed in vacuum tubes. Some larger specimens of the iron meteorites, Nejed and Obernkirchen, cut so that they were of a size and shape suitable for forming the poles of an arc lamp, having afterwards been kindly placed at my disposal by the Trustees of the British Museum, it became possible to study the arc spectra of these meteorites under very favourable conditions, all impurities introduced by the use of the carbon poles being thus avoided. The region of the spectrum photographed extends from K to D, in the case of each meteorite, and in addition to the solar spectrum, that of electrolytic iron, prepared by Professor Roberts-Austen, referred to in a previous communication, has been used as a comparison spectrum in one case.

The Design of an Infra-Red Interferometer

1972 ◽  
Vol 2 (2) ◽  
pp. 113-114
Author(s):  
K. Harwood
Keyword(s):  
Fourier Transform ◽  
Chemical Composition ◽  
Physical Properties ◽  
Fourier Transform Spectrometer ◽  
Atmospheric Absorption ◽  
Amount Of Information ◽  
Earth’S Atmosphere ◽  
Maximum Resolution ◽  
Infra Red ◽  
Earth's Atmosphere

Spectrometers give information on the chemical composition and physical properties of celestial objects. The Earth’s atmosphere restricts the observable spectra to windows in the absorption. Most of these windows are less than one octave wide. To increase the amount of information gained, it is necessary to increase the resolution of the spectrometers. With the advent of balloons, rockets and spacecraft, it is possible to make observations free from atmospheric absorption and it is possible to gain more information by increasing the bandwidth of spectrometers. This paper describes an infra-red Fourier transform spectrometer. The interferometer has a bandwidth of over one decade, from 500 to 5,000 cm-1, with a maximum resolution of 10 cm-1. The resolution can be electronically controlled. There are no absorbing or refracting parts in the interferometer and the resolution is limited by mechanical considerations.

scholarly journals IX. On the lines of the solar spectrum

1860 ◽  
Vol 150 ◽  
pp. 149-160 ◽  
Keyword(s):  
Nitrous Acid ◽  
Royal Society ◽  
Solar Spectrum ◽  
Human Vision ◽  
The Sun ◽  
Continuous Line ◽  
Acid Gas ◽  
Principal Lines

In a paper published in the Transactions of the Royal Society of Edinburgh for 1833, Sir David Brewster stated that by various means he had examined the lines of the solar spectrum, and those produced by the intervention of nitrous acid gas, and had delineated them on a scale four times greater than that employed in the beautiful map of Fraunhofer. Some portions also, which were more particularly studied, had been drawn on a scale twelve times greater. "Fraunhofer,” he continued, "has laid down in his map 354 lines, but in the delineations which I have executed, the spectrum is divided into more than 2000 visible and easily recognized portions, separated from each other by lines more or less marked, according as we use the simple solar spectrum, or the solar and gaseous spectrum combined, or the gaseous spectrum itself, in which any breadth can be given to the dark spaces.” None of these drawings, however, were published at the time. Frequent observations were continued during the years 1837, 1838, and 1841; and now, after a lapse of many years, the various delineations, having been collated and arranged by Dr. Gladstone, form the principal diagrams in the Plate accompanying this paper. Fig. 1 of Plate IV. represents the lines observed when the sun was at a considerable altitude above the horizon, and its light was examined by means of a good prism and telescope. The spectrum is delineated on so large a scale that it was necessary to divide it into two portions, the upper diagram representing the part between the least refrangible end and the line designated F 7, the lower diagram the part between F 7 and the most refrangible end. On a comparison with Fraunhofer’s large map, the principal lines and features will be easily recognized; but it will be seen that every portion of the spectrum contains lines wanting in the earlier drawing, and that parts which Fraunhofer has marked by one line are resolved into groups of bright spaces alternating with dark lines. The figure of the spectrum extends at the more refrangible or violet end to about the same distance as that of the Bavarian philosopher, but it exhibits a considerable extension at the red or less refrangible end. The principal lines are indicated by those letters, A, a , B, C, &c., which were assigned to them by him, and the larger intermediate lines are marked by numbers, 1, 2, 3, &c., beginning afresh on the more refrangible side of each letter; so that any one of these may be expressed by a combination of a letter and numeral; as, for instance, C 6, a remarkable line in the orange, of which much will be said hereafter. The extreme violet is lettered, both in this and in a map to be subsequently described, by that continuation of the alphabet which has been adopted by M. Becquerel. It was necessary to indicate in some similar manner the newly published, though not newly discovered, lines at the red end of the spectrum; and as the alphabet has not been appropriated by M. Becquerel beyond P, and it is not likely that further research will largely extend the spectrum in that direction, it was thought safe to take the end of the alphabet, and denoting the first strongly-marked line before A by Z, to work backwards into those slightly refrangible rays, which have been as yet unresolved by human vision. Some of the dark spaces of the spectrum are of an appreciable breadth, in which case they are represented as bands; and where the observation of a line was indistinct or uncertain, it is marked by an interrupted instead of a continuous line.

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