194 Str John Herschel and Modern Astronomy. (April, 
tides. If the mean distance of the moon were diminished by only 
one-tenth of its actual amount, the mean rise and fall of the tides 
would be increased by a full third of their present quantity, which 
would, of course, produce a great increase in their erosive action on 
the continents, as well as in the transporting powers of the waters 
of the ocean over the materials of the land. He shows, too, how 
the secular variation of the eccentricity of earth’s orbit may have 
produced both-warmer and colder periods than the present. This 
idea, after lying dormant for thirty years, has recently been revived 
and extended by Mr. Croll, in several papers written on this subject, 
which is now materially affecting the reasoning of geologists re-- 
garding the history of ancient formations and the measure of 
geological time. 
Tt is not possible within the limits placed at our disposal to 
mention several papers of great value which have from time to time 
appeared in the ‘ Memoirs of the Astronomical Society,’ ‘'The Trans- 
actions of the Royal Society,’ and in journals devoted to scientific 
literature. Amongst the more remarkable of those contributions, 
to our knowledge may be mentioned a paper investigating orbits 
of double stars ; and another, “ Determination of the most probable 
Orbit of a Binary Star,” which were published by the Astronomical 
Society. “A notice of an error of two days, left uncorrected in the 
Gregorian reformation of the calendar,” appeared in the ‘ Athenzeum.’ 
A paper “On a new Projection of the Sphere” was read by Sir 
John Herschel before the Royal. Geographical Society in 1859. 
The principle of this projection was included in some of Gauss’s 
general formule, but this was unknown to Herschel, and it had 
never before been reduced to a chart. - The article “ Telescope” in 
the ‘Encyclopedia Britannica’ was from Sir John Herschel’s pen. 
(This is the only place in which will be found an account of the 
method of polishing specula, adopted by Sir William Herschel.) 
A Catalogue of Nebule and Stars, 5,078 in number, in order of 
right ascension, brought up to 1860, with precession for 1880, and 
descriptions, was prepared for the Royal Society in 1863. ‘The 
Quarterly Journal of Science’ in 1864 has a paper “On the Solar 
Spots” from the pen of this astronomer, in which he considers the 
speculation on the gradual variation of density in the solar atmo- 
sphere “an aggregation of the luminous matter in masses of some 
considerable size, and some certain degree of consistency, suspended 
or floating at a level determined by their specific gravity mm a non- 
luminous fluid—be it gas, vapour, liquid, or that mtermediate state 
of gradual transition from liquid to vapour which the experiments 
of Caignard de la Tour have placed visibly before us.” To this 
article we refer our readers for an examination of this original idea. 
Sir John Herschel in 1839 received from Oxford an honorary 
D.C.L.; in 1842, he was elected Lord Rector of Mareschal College, 
