Among the curiosities of the microscopic world which Ehrenberg has investigated, we may notice in this place, as likely to interest our readers, his singular suggestion in relation to the foundations of the city of Berlin. This city stands in the midst of an infertile flat plain, through which the river Spree wends its slow way, passing through the centre of the city itself. Beneath the present “streets of palaces and walks of state” exists a deep bog of black peat, through which sinkings and borings in search of water have frequently been carried. This peat, at the depth of fifty feet below the surface, swarms at this moment with infusorial life. Countless myriads of microscopic animals, at this great depth, beneath the pressure of the superincumbent earth and streets, live and die in the usual course of microscopic life. They move among each other, and wriggle, to human sense, invisible; so that the whole mass of peaty matter is in a state of constant and usually insensible movement. But in Berlin the houses crack at times, and yawn and suffer unaccountable damage, even where the foundations seem to have been laid with care. And this, our philosopher has conjectured, may be owing to the changes and motions of his invisible world—the sum of the almost infinite insensible efforts of the tiny forms producing at times, when they conspire in the same direction, the sensible and visible movements of the surface by which the houses that stand upon it are deranged! The conjecture is curious, the cause a singular one, but who shall say that it is inadequate to the effect? Another among the names above mentioned—that of Mitscherlich—stands in relation to the crystalline forms of matter in a nearly similar relation to that which Ehrenberg occupies in regard to microscopic life. The discoverer, at an early period of his life, of what is called the doctrine of Isomorphism, he has lived to see his discovery assume a most important place in chemico-crystallographic science, and to branch out into various kindred lines of research; and at the same time has the happy satisfaction of feeling that he has himself always led the progress, and that he is acknowledged everywhere as still the principal advancer and head authority in the department of knowledge he was the first to open up. But among the scientific men of Berlin, we must spare a few words for one who shines among them as the acknowledged chief—the veteran and venerable Alexander Von Humboldt. Here is Professor Silliman’s description of the old gentleman, as the American Professor saw him, by appointment, in the autumn of 1851:—