scholarly journals On the iron flame spectrum and those of sun-spots and lower-type stars

1911 ◽  
Vol 86 (583) ◽  
pp. 78-80
Keyword(s):  
Low Temperature ◽  
Royal Society ◽  
Electric Energy ◽  
The Other ◽  
Light Sources ◽  
The Sun ◽  
Metallic Elements ◽  
Solar Type ◽  
Higher Temperature ◽  
Sun Spots

In 1897 I announced to the Royal Society that the lines in the spectra of the metallic elements might be separated into two series, one seen best and sometimes alone in the hotter stars, and when higher temperature and electric energy were employed, these I termed "enhanced lines"; the other set, not visible in the hotter stars, but in stars of the solar type, and seen best with lower degrees of heat and electric energy in the laboratory, were referred to as "arc lines." In a previous paper, published in 1904, I pointed out that the similarity of spot spectra and that of Arcturus depended upon the equality in temperature of the vapours existing in these celestial light sources. At this time it was held by Prof. Hale and his colleagues, who had studied and published in detail the lines in these spectra indicated the presence on such stars of many spots like those on the sun. In a later publication, however, they state that their recent work has led them to the opinion that the comparatively low temperature of these stars offers the simplest explanation of the observations.

III. Spectroscopic observations of the sun

1867 ◽  
Vol 15 ◽  
pp. 256-258 ◽  
Keyword(s):  
The Other ◽  
The Sun ◽  
Chemical Action ◽  
Spectroscopic Observations ◽  
Gaseous Mass ◽  
Other Hand ◽  
Sun Spots ◽  
Physical Constitution ◽  
Upward Current

The two most recent theories dealing with the physical constitution of the sun are due to M. Faye and to Messrs. De la Rue, Balfour Stewart, and Loewy. The chief point of difference in these two theories is the explanation given by each of the phenomena of sun-spots. Thus, according to M. Faye, the interior of the sun is a nebulous gaseous mass of feeble radiating-power, at a temperature of dissociation; the photosphere is, on the other hand, of a high radiating-power, and at a temperature sufficiently low to permit of chemical action. In a sunspot we see the interior nebulous mass through an opening in the photosphere, caused by an upward current, and the sun-spot is black, by reason of the feeble radiating-power of the nebulous mass.

scholarly journals I. Researches on the spectra of meteorites. A report to the Solar Physics Committee. Communicated to the Royal Society at the request of the committee

1888 ◽  
Vol 43 (258-265) ◽  
pp. 117-156 ◽  
Keyword(s):  
Royal Society ◽  
Solar Physics ◽  
Solar Spectrum ◽  
The Sun ◽  
Metallic Elements ◽  
Chemical Constitution

Some years ago I commenced a research on the spectra of carbon in connexion with certain lines I had detected in my early photographs of the solar spectrum. I have been going on with this work at intervals ever since, and certain conclusions to which it leads, emphasising the vast difference between the chemical constitution of the sun and of some stars, recently suggested the desirability of obtaining observations of the spectra of meteorites and of the metallic elements at as low a temperature as possible. I have latterly, therefore, been engaged on the last-named inquiries. The work already done, read in conjunction with that on carbon, seems to afford evidence which amounts to demonstration on several important points.

2. On Sun Spots, and their connection with Planetary Configurations

1866 ◽  
Vol 5 ◽  
pp. 213-214
Author(s):  
Balfour Stewart
Keyword(s):  
The Other ◽  
The Sun ◽  
Other Hand ◽  
Sun Spots

The author was led to examine the sun pictures taken by the Kew Photoheliograph, with the view of ascertaining if any connection exists between the behaviour of sun spots and planetary configurations.It was found, that when any portion of the sun's disc recedes by virtue of rotation from the neighbourhood of Venus, it acquires a tendency to break out into spots, and, on the other hand, when such approaches Venus, there is a tendency towards the healing up of spots. Carrington's observations were then discussed, which seem to show that, on the whole, the sun's surface is fullest of spots when Jupiter is furthest from our luminary, and freest from spots when he is nearest.

scholarly journals An account of the heat of July, 1825; together with some remarks upon sensible cold

1833 ◽  
Vol 2 ◽  
pp. 260-261
Keyword(s):  
Low Temperature ◽  
Human Body ◽  
Atmospheric Temperature ◽  
The Other ◽  
The Sun ◽  
Powerful Effect ◽  
External Branch ◽  
Rate Of Cooling

The temperatures which Dr. Heberden wishes to record in this paper, are those observed on the 15th, 17th, 18th, and 19th of last July, and were respectively 92°, 90°, 96°, and 95°. On the 15th, the wind was S.W ., on the other days it blew from the East. The thermometer employed was sensible and accurately graduated, and was suspended upon a lawn, about 5½ feet from the ground; on the first day, in the shade of a laburnum tree, and afterwards from an external branch of a large Portugal laurel; always distinct from any building; exposed to the full influence of the wind, and at the same time sheltered from the actual rays of the sun, and from substances heated by them. The author adds, that the only instance on record of a corresponding elevation of atmospheric temperature was in July, 1808; on the 13th of which month, it appears from the Royal So­ciety’s register, the thermometer rose to 93°.5, and Mr. Cavendish’s thermometer, at Clapham, to 96°. By way of comparison, Dr. He­berden observes, upon the authority of the late Dr. Hunter, that in the hottest season, and during the hottest part of the day, the range of the thermometer, at Kingston, in Jamaica, is from 85° to 90°. To these remarks, Dr. Heberden adds some observations on the imperfection of the thermometer, as a measure of the degree of cold perceptible to the human body in its ordinary exposure to the atmo­sphere, and which depends upon the rapidity with which its own heat is carried off by the conducting power and currents of the at­mosphere. To estimate this insensible cold, the author raised the thermometer to 120°, and then carried it into the open air. As soon as the mercury had fallen to 100°, the rate of its further descent, during every 10'', was noted for half a minute, in different states of the atmosphere in regard to wind and moisture. These experiments, which are given in the form of tables, show the powerful effect of wind in increasing the rate of cooling, and consequently of exciting the sensation of cold in the human body, independent of any actual low temperature of the atmosphere.

scholarly journals XII. Spectroscopic observations of the sun.—No. II

1869 ◽  
Vol 159 ◽  
pp. 425-444 ◽  
Keyword(s):  
Royal Society ◽  
The Sun ◽  
Spectroscopic Observations ◽  
Sun Spots

In my first paper under the above title, kindly communicated by Dr. Sharpey to the Royal Society in 1866, was contained an account of the determination of the nature of Sun-spots by means of the spectroscope. The paper concluded as follows:— “May not the spectroscope afford us evidence of the existence of the 'red-flames’ which total eclipses have revealed to us in the sun’s atmosphere, although they escape all other methods of observation at other times? and if so, may we not learn something from this of the recent outburst of the star in Corona?”

scholarly journals On the periodicity of sun-spots

1911 ◽  
Vol 85 (575) ◽  
pp. 50-53 ◽  
Keyword(s):  
Magnetic Storm ◽  
Royal Society ◽  
September 11 ◽  
The Sun ◽  
Additional Material ◽  
Previous Communication ◽  
Sun Spots ◽  
The Mean

In the year 1906 I presented to the Royal Society an investigation in which it was shown that the frequency of sun-spots was subject to recurrent variations, not only in the well-known 11 years’ cycle, but also in other periods, which were determined. As we now possess additional material extending over 10 years, it is interesting to examine how far the minor maxima of the subsidiary periods can be traced in the more recent records. The accompanying figure gives diagrammatically the sun-spot areas measured at Greenwich between 1898 and 1909. The numbers plotted represent the sum of the mean areas during four successive rotations, beginning with the four rotations 593/596 of Carrington’s series. There is a period of 4.79 years, which in the previous communication was shown to be persistent during the whole time covered by sun-spot records, more persistent, in fact, than that of 11 years. I have marked on the diagram the predicted times of maxima of the period with an arrow pointing upwards. The first maximum, towards the end of the year 1898, which was timed to arrive during the rotation 604, actually took place three rotations, or about months, earlier. The second maximum (September, 1903) was predicted to take place during rotation 668. It actually took place during the rotation 671, though an almost equally strong maximum was observed during rotation 667. We may therefore say that there is here an almost absolute coincidence in the predicted and observed times. The maximum of July, 1908, was delayed by about two months, but the activity had already risen considerably at the predicted time. In all three cases the coincidences of the predicted and actual times are very satisfactory, if it be remembered how variable is the observed maximum of the 11 years’ period. This periodicity of 479 years seems characterised by one or two sharp outbreaks near the time of the maximum, and throughout the time that accurate records are available it nearly always shows itself in each cycle as a separate peak in the curve representing sun-spot frequencies. The outbreaks of sun-spots connected with this period can be traced also in the magnetic records. There were several disturbances during September and October, 1898, notably one on September 9. In 1903 there was a magnetic storm on October 12, and more violent ones at the end of the month. Finally, in 1908, we had strong distxirbances on September 11 and 29.

scholarly journals III. On the form of the sun-spot curve - On the connexion of sun-spots with planetary configuration

1871 ◽  
Vol 19 (123-129) ◽  
pp. 392-393
Keyword(s):  
The Other ◽  
The Sun ◽  
Real Form ◽  
Sun Spots ◽  
The Mean

Of these two series of investigations, one is by Professor Wolf, the other by M. Fritz, communicated to Wolf. In the first, Prof. Wolf has proposed to himself to find the mean cha­racter of the curve of sun-spots, i. e . its real form from one minimum to another.

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

1875 ◽  
Vol 165 ◽  
pp. 157-160
Keyword(s):  
Rainy Season ◽  
Royal Society ◽  
General Procedure ◽  
Solar Spectrum ◽  
The Other ◽  
The Sun ◽  
Single Group ◽  
Short Period ◽  
Clear Atmosphere ◽  
Do So

The spectroscopic observations hereafter discussed were made with instruments belonging to the Royal Society, and in accordance with certain suggestions which a Committee were good enough to make in connexion with my letter to Sir Edward Sabine, President, dated 13th February, 1866. In view of my residence at a considerable height, and the exceedingly clear atmosphere prevailing at some periods of the year, it was suggested that the locality was peculiarly favourable for comparing the solar spectrum when the sun was high with the corresponding spectrum at sunset; any differences between these aspects which might appear were to be noted on Kirchhoff’s well-known maps. Accordingly I set to work with the spectroscope first supplied to me (hereafter distinguished by the prefix old ), and during the autumns of 1868 and 1869 I mapped the differences in question from the extreme red to D: these results appeared in the ‘Proceedings of the Royal Society,’ No. 123, 1870, the Map being marked vol. xix. pl. 1; it is unnecessary, therefore, to dwell on this portion of my labours, excepting to add that the definitions and general procedure there adopted have been retained in the remarks which follow. 2. The observations hereafter noticed were always taken in the autumn , when, the rainy season having passed away, the atmosphere on these mountains is exceedingly clear, so that the sun, the object of inquiry, is bright even to his setting, and a spectrum may therefore be then obtained through a long stretch of terrestrial atmosphere corresponding to the height of the station of observation; on the other hand, with the sun about the meridian, the height of station places the observer above a relative amount of atmosphere, so that the spectrum obtainable at this time and about sunset are highly eligible for the comparison in view. Accordingly the two spectra are given in the accompanying map (Plate 25); and for easy comparison they are placed in juxtaposition. By “sun high” is to be understood any position for the sun within a couple of hours of the meridian; by “sun low” that the sun was within 3 or 4 diameters of his setting and yet quite bright. Indeed it is only when very near sunset that the marked alterations in the lines appear; so that the spectrum required is not only rarely obtainable, but it hardly lasts beyond 10 minutes of an evening. In this short period (when, moreover, the observer is fatigued with previous watching) changes from the sun-high spectrum must first be detected; then their position must be identified, and, failing this, found by measurement; next, the appearance should be drawn, and finally the drawing should be compared with the original: under these conditions a week may be easily absorbed by a single group. It is also to be borne in mind that no human eye will endure, without at least temporary injury, protracted watching of the bright solar spectrum for more than four or five weeks at a time; indeed, though I habitually used both eyes as a relief to one another, they both invariably suffered, and continued to do so for several weeks after every autumn. The following facts may be here mentioned:—

Pressure Dependence of Magnetic States of UGe2

2003 ◽  
Vol 802 ◽  
Author(s):  
Alexander B. Shick ◽  
Václav Janiš ◽  
Václav Drchal ◽  
Warren E. Pickett
Keyword(s):  
Low Temperature ◽  
Pressure Dependence ◽  
The Other ◽  
Scattering Data ◽  
Band Theory ◽  
Higher Temperature ◽  
Degenerate States ◽  
Magnetic States ◽  
Orbital Character ◽  
Polarized Neutron Scattering

ABSTRACTThe correlated band theory picture (LSDA+U) has been applied to UGe2, in which superconductivity has been found to coexist with robust ferromagnetism. Over a range of volumes (i.e. pressures), two nearly degenerate states are obtained, which differ most strikingly in their orbital character (on uranium). The calculated moment, and its separation into spin and orbital parts, is consistent with recent polarized neutron scattering data. These two states are strong candidates for the two ferromagnetic phases, one low-temperature -- low-pressure, the other higher-temperature -- higher pressure. Magnetic waves built from fluctuations between these uranium configurations provide a possible new mechanism of pairing in UGe2.

scholarly journals The absorption spectra of lithium and cæsium

1911 ◽  
Vol 85 (575) ◽  
pp. 54-58 ◽  
Keyword(s):  
Royal Society ◽  
Alkali Metals ◽  
Principal Series ◽  
Steel Tube ◽  
The Other ◽  
Absorption Tube ◽  
Glass Silica ◽  
Complete Series ◽  
Higher Temperature ◽  
Oscillation Frequencies

In a paper communicated to the Royal Society in February, 1910, I gave the results of measurements of absorption lines for the three alkali metals, potassium, rubidium, and cæsium. Up to that time I had not been able to obtain the corresponding spectrum for lithium vapour. This was owing to the fact that lithium vaporises at a considerably higher temperature than the other alkali metals, and at the high temperatures required for a sufficient density of vapour the lithium attacks the material of all tubes which I was able to use. Steel, brass, platinum, glass, silica, carbon are all attacked, and no satisfactory photographs could be obtained. Recently, however, by using a relatively large quantity of lithium in a steel tube sufficient vapour was obtained to give an absorption spectrum showing 27 lines of the principal series. The method was the same as that described in the paper referred to, with the exception that a second steel tube was placed in the outer steel absorption tube. This was simply for the protection of the outer tube, which would probably collapse after being acted on by lithium vapour at the bright red heat to which it was raised. The source of light used was the cadmium spark, as the limit of the series is so much further in the ultraviolet than in the case of the other alkali metals. The following table gives the wave-lengths and oscillation frequencies for the complete series of lithium lines. (See Table I opposite.)

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