322 ANNUAL OF SCIENTIFIC DISCOVERT. 



each square contimotre of the surface of the corona would rocc4ve 

 several tlion-aml units of heat per minute. 1 am well aware tliat 

 my results are ai \ arianee with those obtained by previous ob- 

 servers, ineludinj^ some of the most eminent astronomers of the 

 day; but, as tar as 1 can learn, this form of polariscop(i has not 

 been used for the purpose, and therefore hope that my experiment 

 may be n'peated durinic the next (M'lipsc, 



Since wriiinic the above, 1 learn, from Prof. F. II. Smith, that 

 an excellent Ara<^o\s polariseope was used in Eden Ridge, Tenn., 

 in observing the eclipse. The result agreed with mine, nami'ly, 

 that no traees ot polarization could be detected in the corona with 

 this instrument. 



OBSERVATIONS ON THE PROTUBERANCES OF THE SUN. 



ZoUncr has conmiunicated to the Royal Society of Sciences of 

 Saxony the results of obseivations of the solar protuberances 

 made by a new method, tlie details of which are, however, not 

 given in the paper IVom which this abstract is taken. The author 

 states that by this method the; prouiberanees can be observed with 

 great sharpness and distinctness, and gives a number of figures 

 of much interest, representing various forms of the red eruptive 

 flames. The method of observation employed gives the same 

 protuberance in thri'e dill'erent colors at the same time, corre- 

 sponding to the three homogeneous lines of the spectrum, red, 

 yellow, and blue. A marked difference is observed between the 

 yellow and the other two images. The yellow image is very in- 

 tense near to the edge of the sun's disc, where it corresponds with 

 the other images, wliile at a greater distance the liner details are 

 lost. Zollner infers from this, either that the rays to which the 

 yellow image is dtie proceed from a gas specifically heavier than 

 hydrogen, and, therefore, occupying a lower stratum, or that the 

 increase in the temperature and pressure of the hydrogen near 

 the surface of the sun determines the emission of the yellow rays 

 in question. The author remarks that the protuberances, as seen 

 by his method, for the most part strongly resemble the various 

 forms of terre^trial clouds, the cumulus type being most distinctly 

 exhibited. There are, however, some exceptions; in certain cases 

 the phenomena resemble those of eruption of volcanoes or of hot 

 springs. Zollner suggests that it may hereafter be possible to ob- 

 serve at the same time all the protul)eranees as in the case of a 

 total eclipse. In conclusion the author mentions another observa- 

 tion of great interest. On the 27th June the slit of the spectro- 

 scope was made to approach a part of the sun's disc where the 

 speetral lines of the protuberances were particularly long and 

 bright. At a distance of o or 4 minutes above the sim's edge, the 

 whole length of the spectrum was crossed by bright linear flashes. 

 These flashes extended over the whole portion of 5>pectrum in the 

 field of view, and w<n*e so abundant at one; point of the sun's edge 

 that it seemed as if the whoh; spectrum were crossed by the 

 straight paths of rapidly following electric discharges. This phe- 



