Continuing his career of scientific industry, he issued, in 1849, his important and very valuable treatise entitled “Outlines of Astronomy.”  In 1845, he was appointed President of the British Association; and in 1848, of the Royal Astronomical Society.  To his other honours was added that of Chevalier of the Prussian order, “Pour la Merite,” founded by Frederick the Great, and bestowed at all times with a discrimination which renders it a deeply-coveted distinction.  Of the academies and leading scientific institutions of the Continent and the United States, he was also an honorary or corresponding member.

Besides his works on meteorology and physical geography, he published, in 1867, an admirable little volume—­“Familiar Lectures on Scientific Subjects.”  In this he showed that he could write with as much ease and intelligibility for the general public as for the higher order of scientific inquirers.  His style in this valuable manual of information has a charm of its own, and entices the reader into the consideration of subjects apparently abstruse.  He is earned on from page to page without any great mental effort, and finds himself rapidly mastering difficulties which he had been accustomed to regard as insuperable.

Let us take the first lecture on “Volcanoes and Earthquakes,” and obtain a glimpse of Herschel’s mode of treatment.  He refers to the greater and more permanent agencies which affect the configuration of our planet.  Everywhere, he says, and along every coast-line, we see the sea warring against the land, and overcoming it; wearing it and eating it down, and battering it to pieces; grinding those pieces to powder; carrying that powder away, and spreading it out over its own bottom, by the continued effect of the tides and currents.  What a scene of continual activity is presented by the chalk-cliffs of Old England!  How they are worn, and broken up, and fantastically sculptured by the influence of winds and waters!  Precipices cut down to the sea-beach, constantly hammered by the waves, and constantly crumbling; the beach itself made of the flints outstanding after the softer chalk has been ground down and washed away; themselves grinding one another under the same ceaseless discipline—­first rounded into pebbles, then worn into sand, and then carried further and further down the slope, to be replaced by fresh ones from the same source.  Here the likeness of an old Gothic cathedral, with lofty arch, and shapely pinnacle; there the similitude of a mass of medieval fortifications, with crumbling battlements and shattered towers!

The same thing, the same waste and wear, is going on everywhere, round every coast.  The rivers contribute their share to the great work of change.  Look at the sand-banks at the mouth of the Thames.  What are they, says Sir John Herschel, but the materials of our island carried out to sea by the stream?  The Ganges carries away from the soil of India, and delivers into the sea, twice as much solid substance weekly as is contained in the Great Pyramid of Egypt.  The Irawaddy sweeps off from Burmah sixty-two cubic feet of earth in every second of time, on an average Sometimes vast amount of earthy materials is transferred from one locality to another by river agency, as is the case in the deltas of the Nile and the Mississippi.