no THE POPULAR SCIENCE MONTHLY. 



of accomplishing at will those delicate fermentations which pro- 

 duce 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, lith- 

 arge, white lead, the sulphurets of arsenic and arsenious acid ; 

 remedies and poisons were composed at the same time, for differ- 

 ent 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 profes- 

 sions 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 monu- 

 ments, arms, potters' and glass ware, cloths, gems and jewels, and 

 art objects of every kind which have come down to us. Such ex- 

 amination furnishes, in fact, incontestable results, provided the 

 dates of the objects are certain, and they have not suffered res- 

 toration. 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 contem- 

 porary 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 independ- 

 ent of the ulterior progress of the industry. We have a still 

 surer and more exact class of data than the chronicles in the tech- 

 nical treatises and works concerning arts and trades which have 

 come down to us, whenever those treatises have an ascertained 



