the series, sosses, ners, and sars, being employed in all estimations of values.  Years and measures of length were reckoned in sosses, while talents and bushels were measured in sosses and sars.  The fact that these subdivisions were all divisible by 10 or 12, rendered calculations by means of them easy to the merchant and workmen as well as to the mathematical expert.  The glimpses that we have been able to obtain up to the present of Chaldaean scientific methods indicate that they were on a low level, but they were sufficiently advanced to furnish practical rules for application in everyday affairs:  helps to memory of different kinds, lists of figures with their names phonetically rendered in Sumerian and Semitic speech, tables of squares and cubes, and rudimentary formulas and figures for land-surveying, furnished sufficient instructions to enable any one to make complicated calculations in a ready manner, and to work out in figures, with tolerable accuracy, the superficial area of irregularly shaped plots of land.  The Chaldaeans could draw out, with a fair amount of exactness, plans of properties or of towns, and their ambition impelled them even to attempt to make maps of the world.  The latter were, it is true, but rough sketches, in which mythological beliefs vitiated the information which merchants and soldiers had collected in their journeys.  The earth was represented as a disk surrounded by the ocean stream:  Chaldaea took up the greater part of it, and foreign countries did not appear in it at all, or held a position out in the cold at its extremities.  Actual knowledge was woven in an extraordinary manner with mystic considerations, in which the virtues of numbers, their connections with the gods, and the application of geometrical diagrams to the prediction of the future, played an important part.  We know what a brilliant fortune these speculations attained in after-years, and the firm hold they obtained for centuries over Western nations, as formerly over the Bast.  It was not in arithmetic and geometry alone, moreover, that the Chaldaeans were led away by such deceits:  each branch of science in its turn was vitiated by them, and, indeed, it could hardly be otherwise when we come to consider the Chaldaean outlook upon the universe.  Its operations, in their eyes, were not carried on under impersonal and unswerving laws, but by voluntary and rational agents, swayed by an inexorable fate against which they dared not rebel, but still free enough and powerful enough to avert by magic the decrees of destiny, or at least to retard their execution.  From this conception of things each subordinate science was obliged to make its investigations in two perfectly distinct regions:  it had at first to determine the material facts within its competence—­such as the position of the stars, for instance, or the symptoms of a malady; it had then to discover the beings which revealed themselves through these material manifestations, their names and their characteristics.  When once it had obtained this information, and could lay its hands upon them, it could compel them to work on its behalf:  science was thus nothing else than the application of magic to a particular class of phenomena.