THE APPROACHING TOTAL SOLAR ECLIPSE. 



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THE APPROACHING TOTAL SOLAE ECLIPSE. 



By EICHAED A. PKOCTOE. 



A TOTAL solar eclipse will occur on July 

 29th. It will not be visible in the British 

 Isles or anywhere in Europe, even as a partial 

 eclipse. But it will not be the less closely stud- 

 ied by zealous and experienced astronomers. For 

 the track of the moon's shadow lies athwart the 

 North American Continent, and there are no as- 

 tronomers more zealous or more skillful than the 

 American. In fact, European astronomers have 

 not shown of late an equal earnestness in the 

 study of special astronomical phenomena of in- 

 terest. America went far ahead of all other coun- 

 tries, for example, in her expeditions for the ob- 

 servation of the transit of Venus in 1874. But, 

 without leaving the consideration of solar eclipses, 

 we can recognize the zeal and energy of the 

 Americans in matters astronomical. For though 

 in 1869 a solar eclipse occurred which was visi- 

 ble throughout the United States, and was ob- 

 served as a total eclipse by hundreds of Ameri- 

 cans, yet, when the eclipse of 18*70, called some- 

 times the Mediterranean eclipse, was approaching, 

 America sent a party of skillful observers across 

 the Atlantic to observe it, at a time when English 

 astronomers were in doubt whether an expedition 

 could be managed by this country, though so 

 much nearer to the scene of operations. Indeed, 

 it was commonly believed at the time that, but 

 for the arrival of the American expedition, and 

 certain caustic reflections made in newspapers on 

 the comparative zeal for science shown by Amer- 

 ica and England, the Government could not have 

 been induced to assist English observers in any 

 way. There can be no question that, if the 

 eclipse of this month could have been observed 

 in Europe only, the American Government would 

 again have sent forth an observing party ; but on 

 this occasion, as in the case of the American 

 eclipse of 1869, nothing is farther from the 

 thoughts of our Government than to provide in 

 any way for an English expedition to America. 



It is noteworthy how closely the eclipse of 

 the present month resembles in general respects 

 that of August 7, 1869. The entire region where 

 the eclipse can be seen wholly or in part is almost 

 exactly the same. The lines along which the 

 eclipse ends at sunrise or begins at sunrise, or 

 ends at sunset or begins at sunset, are nearly the 

 same. At a first view, one would say, in looking 

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at a chart in which these regions and lines are 

 depicted, that they are exactly the same, though, 

 on looking more closely, small differences can of 

 course be detected. 



Unfortunately, the two eclipses differ some- 

 what more importantly as to the line of central 

 eclipse than in other respects. In each case the 

 track of the moon's shadow runs along nearly the 

 same part of Siberia, crossing Behring's Straits 

 and traversing what used to be called Eussian 

 America to Behring's Bay ; but from this point 

 the tracks diverge. In 1869 the moon's shadow 

 passed to the cast of British Columbia to Dakota, 

 Iowa, Illinois, Kentucky, and North Carolina. On 

 July 29th it will pass instead through British 

 Columbia, Montana, Wyoming, Colorado, and 

 Texas, crossing the Gulf of Mexico to Cuba and 

 St. Domingo. Along this track there is scarcely 

 any part, except the neighborhood of Denver City, 

 Colorado, where the eclipse can be effectively ob- 

 served, whereas in 1869 the greater part of the 

 track of total shadow lay athwart conveniently 

 accessible regions. 



As regards duration of totality, the two eclipses 

 were closely similar. By-the-way, it is strange, 

 and rather suggestive of the increased interest 

 taken of late in such observations, that the " Nau- 

 tical Almanac " for 1869 gave no notice whatever 

 of the duration of the American eclipse of that 

 year, doubtless because it was deemed, and deemed 

 rightly, that no astronomers would go from Eng- 

 land to the United States to witness it. I find, 

 however, from a rough computation, that the 

 maximum duration must have been about three 

 minutes fifty seconds. The maximum duration 

 of the total solar eclipse of the 29th instant is 

 given by the " Nautical Almanac " as three min- 

 utes twelve seconds. But where the track ap- 

 proaches Denver City, near which most of the 

 observers will probably be, this duration will not 

 exceed two minutes fifty-three seconds. Many 

 observations of extreme interest were made by 

 American observers, however, on August 7, 1869, 

 at places where the totality did not last longer 

 than this ; and we may well believe that the ap- 

 proaching eclipse will also be well observed by 

 them, when we remember how largely observa- 

 tional methods have improved since 1869. 



Before proceeding to consider the recent his- 



