day, a partial eclipse in Athens, the longitude of the IS must have been 

 shorter by about 5° than our Tables state. In this case, however, the 

 eclipses in the Almagest do not come out. Now, I ask, is this eclipse not 

 much more reliable than those in the Almagest not observed by Ptolemy? 

 Further, Livy and the Annales Maximi bear witness that in — 216, Feb- 

 ruary nth, 2h. 30m., a very small eclipse {soli's orbem mmut visum) was 

 seen in Sardinia, which amounted, according to the Ptolemean theory of 

 the moon, to 8 inches, because the IS lay 5° east of the sun, and the curve 

 of the moon's shadow was 0°, 8°, 45°. This contradicts the Annales; the 

 longitude of the 7S must have been shorter by about 4°. Besides, Silius 

 Italicus (viii. 634) reports that the same eclipse was total, or nearly total, 

 in Calabria. Now, the longitude of the IS being shorter by about 4°, this 

 eclipse was really small in Sardinia, but nearly total in Calabria. The 

 passage of Silius Italicus is wanting in my treatise; I found it first in 

 Newcomb's work. Once more, these two facts incontrovertibly demon- 

 strate that Ptolemy's lunar theory is wrong. 



It will be objected, however, that the accelerations of the moon's mo- 

 tions, proposed p. 429, is too great to be effected by the disturbing forces 

 of the planets, and, in general, that they conflict with the law of gravita- 

 tion.. To this I reply, that my figures are but approximate ones, and that 

 it is the problem of professed astronomers to harmonize the different lunar 

 motions with each other. I claim only to have incontrovertibly fixed the 

 chronology of the ancient eclipses. 



At present, the only way for establishing correct Lunar Tables is, as it 

 seems to me, to compute fifty or more authenticated classic eclipses, and 

 to compare them with each other and with modern observations, in order 

 to fix before all the principal elements of Lunar Tables ; the secular mean 

 motions of the moon, her nodes and apsides, and their secular accel- 

 erations. 



Since Prof. Newcomb, p. 279 of his work, says, " the only course will 

 be to make a complete re-examination of all ancient eclipses," I hope that 

 he will take this very course. But should he, however, make the Alma- 

 gest the basis of his new Tables, you will allow me to predict once more 

 that his new Tables will, after twenty years, be as useless as Damoiseau's 

 and Hansen's were in 1S51 and 1876. The loss of several years in the life 

 of a distinguished astronomer like Newcomb would be a great loss for 

 science. 



I myself, being 82 years old, shall not outlive the triumph of the truth; 

 but you, I presume, will see with your own eyes the accomplishment of 

 this prophecy. 



Respectfully yours. 



Prof. Gus. Seyffarth. 

 New York City, Dec. 20, 1878. 



