of accomplishing at will those delicate fermentations which produce bread, wine, and beer, and which modify a large number of foods; also of falsifying wine by the addition of plaster and other ingredients. The art of healing, seeking everywhere for resources against diseases, had learned to transform and fabricate a large number of mineral and vegetable products, such as sugar of poppy, extracts of nightshades, oxide of copper, verdigris,, white lead, the sulphurets of arsenic and arsenious acid; remedies and poisons were composed at the same time, for different purposes, by doctors and magicians. The manufacture of arms and of inflammatory substances—petroleum, sulphur, resins, and bitumens—had already, anciently as well as in our own time, drawn upon the talents of inventors and given rise to formidable applications, especially in the arts of sieges and marine battles, previous to the invention of the Greek fire, which was in its turn the precursor of gunpowder and of our terrible explosive matters.
This rapid review shows how far advanced in the knowledge of chemical industries the Roman world was at the moment when it went to pieces under the blows of the barbarians. But the ruin of the ancient organization came about by degrees: while high scientific study, hardly accessible to coarse minds, ceased to be encouraged, and was gradually abandoned; while the Greek philosophers, knocked about between the religious persecution of the Byzantine emperors and the indifferent disdain of the Persian sovereigns, no longer trained pupils; while the great names of Grecian physics, mathematics, and alchemy hardly passed the time of Justinian, it is still certain that the necessity of professions indispensable to human life, or sought out by sovereigns and priests, could maintain and did maintain effectively most of the chemical industries.
Proofs of various kinds can be brought up in support of these reasonings. Some are drawn from the examination of the monuments, arms, potters' and glass ware, cloths, gems and jewels, and art objects of every kind which have come down to us. Such examination furnishes, in fact, incontestable results, provided the dates of the objects are certain, and they have not suffered restoration. Respecting the date, we can not exercise too much prudence and distrust, whether we are examining buildings or objects in museums. The accounts and descriptions by contemporary historians furnish other data, but less precise, for it is better to have the object in hand than the description. They have the advantage, however, of giving us indications independent of the ulterior progress of the industry. We have a still surer and more exact class of data than the chronicles in the technical treatises and works concerning arts and trades which have come down to us, whenever those treatises have an ascertained