ASTRONOMICAL I'lII'NoMKN A AND 



45 



My tlio end of tho present century, if not 



f, \vr shall ha\ean imle|>emlent test of 



tin.- latter li\ (MithrMs, in tho agreement of tho 

 .I'd ami theoretieal times of the transits 

 rcury and Venus. If the hypothesis is 

 a truo one, tho irregularities may range over 

 half a minute of time in the course of a cen- 

 tury, ami this quantity might be detected even 

 !iy meridian observations of the planets in 

 question." 



The Lunar Eclipse of July 12th. This phe- 

 nomenon was carefully observed in many parts 

 of Kngland, aiid fully reported to tho " Ob- 

 s ,T\ ing Astronomical Society." The following 

 are some of tho most interesting points noted. 

 Tho Rev. Ralph Prowde, of Northallcrton, 

 Yorkshire, says: "I observed the eclipse of 

 tlio moon on the 12th, but tho only thing re- 

 markable was tho great contrast of shade be- 

 tween tho darker and brighter pcnumbrao. I 

 say penumbras, for I suppose the real umbra 

 of tlio earth's shadow falls within the moon's 

 orbit. Tho darker interior cone of shadow 

 obscured the edge of the moon and the object 

 on its surface, as it passed over them, almost 

 entirely, but its own edge did not seem to be 

 nearly so regularly round as the lighter envel- 

 oping cone of shade." The Rev. J. J. John- 

 son, of Crediton, reports: "On the evening 

 of the 12th I had a very favorable view of the 

 lunar eclipse. The sky was clear at first, with 

 a small amount of stratus near the horizon. I 

 first caught sight of the moon at 8.41, but it 

 was 8.49 before it got clear of the clouds. I 

 paid particular attention to the degree of dis- 

 tinctness with which the eclipsed portion 

 could be seen. When about four digits were 

 covered, I just noticed the copper tint through 

 the telescope. I fancy this would be a little 

 sooner than in the last eclipse I observed (Sep- 

 tember, 1867), but in that of October 4, 18G5, 

 which was only of four digits, the copper tint 

 was very decided in the telescope at the time 

 of the greatest obscuration. When about six 

 digits, or half the disk, were covered, the cop- 

 per color could be clearly seen with the naked 

 eye. I could not make out any particular 

 parts of the moon's surface until 9.36, when I 

 noticed the Mare Tranquillitatis and the Mare 

 Serenitatis showed with beautiful distinctness 

 through tho earth's shadow in the telescope. 

 A few minutes after the total was attained, I 

 was struck with the obscurity of the eastern 

 side of the moon being so much more than I 

 had expected. At 9.55 at least half of its sur- 

 face was as if blotted out, even when seen 

 through the telescope, although I applied two 

 different powers 70 and 150. Three of the 

 seas at the western side were all I could make 

 out. Possibly a thin coating of cirrus cloud, 

 which covered all tho sky about this time, 

 mi^ht account in some measure for the invisi- 

 bility of the moon. By 10.30 this had entirely 

 cleared away, and the sky was everywhere cov- 

 ered with stars. The Milky Way very near the 

 moon was about as distinct as it usually ap- 



pears on ft dark, clear ui;:ht. At this period, 

 t lie middle of tho eclipse, the upper por- 

 tion of the moon was the invisible part, all 

 th-i-o regions lying round tho margin of tho 

 disk being alone to bo seen, except at the ver- 

 tex, where the margin itself was not discern- 

 ible. At 11.23 the first streak of light was 

 breaking forth at the eastern edge. At 11.45 

 tho red color was nearly gone, and the eclipsed 

 part appeared of a gray color. At 11.58 I no- 

 ticed there was no trace of the Milky Way ; at 

 12.24 the lunar circle was again complete." 

 Mr. Oliver J. Lodge, of Hanley, reports that 

 "the color of the moon during the totality was 

 of a most peculiar copper hue, giving very 

 little light indeed. But during the egress of 

 the shadow it was almost as white and silvery 

 as it usually is, although still under the penum- 

 bra." Mr. Edmund Neison, of London, says: 

 "The color of the eclipsed disk was during 

 the whole time a dull, yellowish olive-green, 

 both in the telescope and out, but was never- 

 dark enough to prevent many of the chief 

 markings and craters being seen. From 10.44, 

 when the lunar disk was fairly above tho fog 1 

 banks, Aristarchus was quite distinct as a 

 bright crater, and even before 11 Grimaldi 

 was plainly discernible." At Bristol, Mr. Wil- 

 liam F. Denning observed the phenomenon, and 

 remarks that even at the time of totality many 

 of the most conspicuous objects on the disk 

 were distinctly visible. The copper tint was 

 also very evident. During a portion of the 

 time the moon was overcast with clouds. 



The Coming Transit of Venus. Astrono- 

 mers in different parts of the world continue 

 to make suggestions to promote accuracy in 

 the observations of the transit of Venus, which 

 takes place in 1874. Mr. Simon Newcomb 

 read a paper on this interesting subject before 

 the National Academy of Sciences in April, 

 in which he recommended two measures to be 

 adopted for the more precise determination of 

 the all-important points of ingress and egress. 

 The first consists in having the observer oc- 

 cupy the entire time in making very careful 

 measures of the cusps with a micrometer best 

 adapted for this purpose. The second is to 

 bring the observers at opposite stations to- 

 gether, both before and after the transit, and 

 cause them to make observations on antipodal 

 transits with the same instrument employed in 

 observing the transit of Venus, in order to de- 

 termine what corrections should be applied to 

 the observations of one of them comparable 

 with those of the other. Mr. Newcomb says : 



It would be a comparatively siraplo operation to 

 erect an artificial representation of the sun's dUk at 

 the distance of a few hundred yards, and to have an 

 artificial planet moved over it by clock-work. The 

 actual time of contact could be determined by elec- 

 tricity, and tho relative positions of the p_lanet and 

 the disk by actual measurement. With this appara- 

 tus it would be easy to determine the personal errors 

 to which each observer was liable, and these errors 

 would approximately represent those of the observa- 

 tions of actual transit. 



Still, it would be very unsafe to trust entirely to 



