So, again, Rome's armies traversed the globe, and her legions were often explorers of hitherto unknown regions. But no men of science, no corps of _savans_ was attached to her cohorts, to march in the footsteps of conquest and gather the fruits of victory to enrich the schools. Provinces were devastated, great cities plundered, nations made captive, and all the masterpieces of Art borne off to adorn Rome. But Nature was never rifled of her secrets; nor was discovery carried beyond the most material things. The military spirit stifled natural science. There were then, to be sure, no tendencies of thought to anything but war, pleasure, literature, or art. There was comparatively no knowledge of the physical sciences, whose culture Mr. Buckle has shown to have exerted so powerful an influence on civilization. The convex lens--as since developed into the microscope, the giver of a new world to man--was known to Archimedes only as an instrument to burn the enemy's fleet. * * * * * Modern pisciculture in some measure imitates, although, it does not rival the ancient. Many methods have been devised in France and England of breeding and nurturing the salmon, the trout, and other valuable fish, which are annually becoming more scarce in all civilized countries. But all this is on a far different principle from that pursued at Rome. We follow pisciculture from necessity or economy, because fish of certain kinds are yearly dying out, and to produce a cheap food; but the Romans followed it as a luxury, or a childish amusement, alone. And although our aldermen may sigh over a missing Chelonian, as Crassus for his deceased eel, or the first salmon of the season bring a fabulous price in the market, yet the time has long passed when the gratification of appetite is alone thought of in connection with Nature. We know that living creatures are to be studied, as well as eaten; and that the faithful and reverent observation of their idiosyncrasies, lives, and habits is as healthful and pleasing to the mind as the consumption of their flesh is wholesome and grateful to the body. The whole science of Zoölogy has arisen, with its simple classifications and its vast details. The _vivaria_ of the Jardin des Plantes rival those of the Colosseum in magnitude, and excel them in object. Nature is ransacked, explored, and hunted down in every field, only that she may add to the general knowledge. Museums collect and arrange all the types of creative wisdom, from the simple cell to man. Science searches out their extinct species and fossil remains, and tells their age by Geology. The microscope pursues organic matter down into an infinity of smallness, proportionately as far as the telescope traces it upwards in the infinity of illimitable space. Last of all, though not till long after the earth and the air had been seemingly exhausted, the desire of knowledge began to push its way into the arcana of the