36 



ASTRONOMICAL PHENOMENA AND PROGRESS. 



less Prof. Tyndall's opinion is correct, that the 

 earth, in common with the other planets, 

 must " creep in, age by age, toward the sun." 

 But, -in that case, the pace is so slow that, in 

 Captain Ericsson's view, his calculations are 

 not seriously affected. He remarks that the 

 computed diminution of solar intensity, 67 

 54 = 13, during the next 2,000,000 years, 

 will probably be deemed extravagant by those 

 who do not bear in mind that the computa- 

 tion is founded on the assumption that a con- 

 stant power is being exerted, during the stated 

 period, capable of developing, as at present, 

 the stupendous energy of 240,000,000 foot- 

 pounds, in a single minute, for each square foot 

 of the surface of a sphere whose diameter 

 exceeds 850,000 miles, all this effect being 

 produced, on the author's theory, ^by the 

 shrinking of the sun, the intensity of its heat 

 being gradually lowered in the process. By 

 the same rule of estimating, he finds that the 

 diminution of temperature during "historic 

 times," or, say, 4,000 years since the building 

 of the Pyramids, has not exceeded ^ of a de- 

 gree of Fahrenheit. 



Elements in the Solar Spectrum. Prof. C. 

 A. Young, who had charge of the spectro- 

 scopic work at the Observatory in Sherman, 

 "Wyoming Territory, under direction of the 

 United States Coast Survey, in July and Au- 

 gust, 1872, made an important report of his 

 labors upon the spectrum of the sun, to Prof. 

 Peirce, superintendent of that service. In 

 addition to the elements before quite conclu- 

 sively demonstrated to reside in the chromo- 

 sphere, the following seem to be positively 

 indicated: sulphur, cerium, and strontium; 

 and the following with a somewhat less degree 

 of probability : zinc, erbium and yttrium, lan- 

 thanum and didymium. There are some coin- 

 cidences also with the spectra of oxygen, ni- 

 trogen, and bromine, but not enough, consid- 

 ering the total number of lines in the spectra 

 of these elements, or of a character, to war- 

 rant any conclusion. One line points to the 

 presence of iridium or ruthenium, and only 

 three lines are known in the whole spectrum 

 of these metals. The coincidences are too 

 many and too close in the associated spectra 

 of iron and calcium, or iron and titanium, to 

 be all the result of accident. Prof. Young 

 gives a complete catalogue of all the bright 

 lines observed by him, at Sherman, to the 

 number of 273, and also a list of the coinci- 

 dences between the observed lines of the spec- 

 tra of the chemical elements. His instruments 

 were a telescope, of 9^ inches aperture (fur- 

 nished by Dartmouth College), and a spectro- 

 scope, automatic, with a dispersive force of 

 12 prisms. The approximate geographical 

 position of Sherman is, longitude, l h 53. 2 m 

 west of "Washington; latitude, 41 0.7'; alti- 

 tude, above sea-level, 8,280 feet; mean height 

 of barometer, about 22.1 inches. 



Signor Tacchini, of Palermo, in a letter to 

 M. Faye, says that, on the 6th of May, he 



found, in the sun, some regions, of great ex- 

 tent, remarkable for the presence of magne- 

 sium, stretching over an arch from 12 to 

 168 ; and that, on the 18th of that month, he 

 presented to the Spectroscopio Societ} r of Pa- 

 lermo a design of the whole border, with in- 

 dications as to the position of the magnesium, 

 and its unaccountable predominance along the 

 western border. On the 18th of June, the 

 magnesium began to show itself, in the spec- 

 troscope, around the whole border, that is, 

 the whole chromosphere was invested with 

 vapors of the metal. Under this general ebul- 

 lition, there was an absence of protuberances, 

 while the flames of the chromosphere were 

 very marked and brilliant, and the more brill- 

 iant the flames, the greater the amount of 

 magnesium indicated. 



Solar Outbursts and Magnetic Storms. 

 Royal Astronomer Airy addressed a note to 

 Nature, commenting upon the supposed coin- 

 cidence between a violent solar outburst, seen 

 by Father Secchi, at Rome, and a magnetic 

 storm, recorded at Greenwich, about the same 

 time. Father Secchi reported having noticed 

 the remarkable solar disturbance on July Yth, 

 and that it lasted from 3 h 30 m to 7 h 50 m (Ro- 

 man time), or nearly 2 h 40 m to 6 h (Greenwich 

 time). Now, a magnetic storm commenced, 

 at Greenwich, at 5 h , precisely, on the same 

 day. Its indications began at that time with 

 unusual suddenness and strength, on all the 

 magnetic indicators, namely, the declination- 

 needle, the horizontal force magnetometer, 

 the vertical force magnetometer, the earth- 

 current wire, in an approximate northeast and 

 southwest direction, and, on the earth-current 

 wire, in an approximate northwest and south- 

 east direction. The disturbance lasted, grad- 

 ually diminishing, to the evening of July 9th. 

 During a part of the time, it was accompanied 

 with aurora. Prof. Airy says: "I do not 

 venture upon the question whether there 

 really was any connection between the solar 

 outburst and the terrestrial magnetic storm, 

 but I will remark that, if there was such con- 

 nection, the transmission of the influence from 

 the sun to the earth must have occupied 2 h 

 20 m , or a longer time if Father Secchi did not 

 see the real beginning of the outburst. This, 

 if established, would be an important cosmical 

 fact; and, at any rate, the notification of this 

 apparent retardation may direct the attention 

 of observers of similar phenomena in future to 

 a new element in their interpretation." 



The Sun's Temperature. There is the 

 widest variance among physicists of high rep- 

 utation regarding the true'temperature of the 

 sun, and every year adds some new view to 

 the great number of theories, already totally 

 irreconcilable. Nearly all the estimates, how- 

 ever far .ipart, are derived from observations 

 upon radiant heat, and some of the experi- 

 menters, who employ almost identically the 

 same apparatus, are millions of degrees away 

 from each other in their conclusions. Cap- 



