SCIENTIFIC SUMMARY. 
311 
only enough brighter than the centre to give it the appearance of a globe, 
but of almost inky blackness.” He remarks, “ Mr. Lockyer, in ‘Nature,’ 
quotes from a letter of mine written nearly a year ago, to show that my 
opinions regarding the nature of the corona have been considerably modified 
since then ; and this is true to a certain extent, though I think the present 
approximation of our views is owing quite as much to a change in his own 
ideas — as would be evident on referring to his papers of the same and even 
somewhat later date. But I should still write, ‘ I am strongly disposed to 
believe that the whole phenomenon (i.e. the corona as I saw it in 1869) is 
purely solar.’ ” In 1869 the atmosphere was far clearer, it is to be noticed, 
than during the eclipse of 1870. 
The Zodiacal Light. — Mr. Birt records some interesting observations of 
the zodiacal light in the “ Monthly Notices of the Astronomical Society ” 
for April. They were made in the earlier months of the year 1850, and 
have remained hitherto (for unknown reasons) unpublished. Mr. Birt, by 
the way, seems unaware of the extensive series of observations of the 
zodiacal light made by German astronomers, for he remarks that so full and 
consecutive a series as his own has not, he believes, been published — a 
strange mistake. However, his observations are interesting in so far as 
they confirm those already made, especially as respects the change in the 
form of the “ light ” as seen at different seasons. He submits, as a new 
theory, the generally accepted explanation that these changes are due to the 
changing position of the observer as the Earth travels onwards on her 
orbit. 
In connection with this subject we must refer to a most preposterous note 
which appears in the same number of the u Notices,” in which an observer 
says, “We think we saw the zodiacal light on Good Friday evening. When 
we first observed it, it was, as nearly as I can tell (for my watch was slow) 
about 7h. 4m., and it lasted about five minutes. It was a little to the north 
of where the Sun had set behind a hill, and the ray of light was nearly per- 
pendicular, and, as nearly as I could guess without means of measurement, 
about a degree broad and five degrees long.” The observation is interesting- 
enough in itself, but can have had no possible connection with the zodiacal 
light, whose appearance and position (at any season) should be too well known 
for such an account as the above to be referred to that phenomenon. 
Orbits of the Binary Stars £ Herculis and £ Cancri. — Mr. W. E. Plum- 
mer, of Mr. Bishop’s Observatory, Twickenham, has re-examined the obser- 
vations made upon these two stars. By means of equations of condition 
founded on observations made on £ Herculis from 1782 to 1869, he obtains 
the following elements 
Date of the periastron 
1866-241 
36*606 years 
Period of the revolution . 
Longitude of the node 
27° 0'-4 
291° 49 A 0 
50° 14'*1 
33° 26'*5 
[2-77090] 
l // *374. 
Longitude of the periastron 
Inclination 
Eccentricity e = 0*55110, <p = 
Mean motion in minutes . 
Mean distance . 
