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FORE:The means of supporting cores must be devised, or at least understood, by pattern-makers; these supports consist of 'prints' and 'anchors.' Prints are extensions of the cores, which project through the casting and extend into the sides of the mould, to be held by the sand or by the flask. The prints of cores have duplicates on the patterns, called core prints, which are, or should be, of a different colour from the patterns, so as to distinguish one from the other. The amount of surface required to support cores is dependent upon their weight, or rather upon their cubic contents, because the weight of a core is but a trifling matter [96] compared to its floating force when surrounded by melted metal. An apprentice in studying devices for supporting cores must remember that the main force required is to hold them down, and not to bear their weight. The floating force of a core is as the difference between its weight and that of a solid of metal of the same size��a matter moulders often forget to consider. It is often impossible, from the nature of castings, to have prints large enough to support the cores, and it is then effected by anchors, pieces of iron that stand like braces between the cores and the flasks or pieces of iron imbedded in the sand to receive the strain of the anchors.We also miss in him their single-minded devotion to philosophy and their rigorous unity of doctrine. The Acragantine sage was a party leader (in which capacity, to his great credit, he victoriously upheld the popular cause), a rhetorician, an engineer, a physician, and a thaumaturgist. The well-known legend relating to his death may be taken as a not undeserved satire on the colossal self-conceit of the man who claimed divine honours during his lifetime. Half-mystic and half-rationalist, he made no attempt to reconcile the two inconsistent sides of his intellectual character. It may be compared to one of those grotesque combinations in which, according to his morphology, the heads and bodies of widely different animals were united during the beginnings of life before they had learned to fall into their proper places. He believed in metempsychosis, and professed to remember the somewhat miscellaneous series of forms through which his own personality had already run. He had been a boy, a girl, a bush, a bird, and a fish. Nevertheless, as we shall presently see, his theory of Nature altogether excluded such a notion as the soul��s separate existence. We have now to consider what that theory actually was. It will be remembered that Parmenides had affirmed the perpetuity and eternal self-identity of being, but that he had deprived this profound divination of all practical value by interpreting it in a sense which excluded diversity and change. Empedocles also declares creation and destruction to be impossible, but explains that the appearances so denominated arise from the union and separation of four everlasting substances��earth, air, fire, and water. This is the famous doctrine of the four29 elements, which, adopted by Plato and Aristotle, was long regarded as the last word of chemistry, and still survives in popular phraseology. Its author may have been guided by an unconscious reflection on the character of his own philosophical method, for was not he, too, constructing a new system out of the elements supplied by his predecessors? They had successively fixed on water, air, and fire as the primordial form of existence; he added a fourth, earth, and effected a sort of reconciliation by placing them all on an equal footing. Curiously enough, the earlier monistic system had a relative justification which his crude eclecticism lacked. All matter may exist either in a solid, a liquid, or a gaseous form; and all solid matter has reached its present condition after passing through the two other degrees of consistency. That the three modifications should be found coexisting in our own experience is a mere accident of the present r��gime, and to enumerate them is to substitute a description for an explanation, the usual fault of eclectic systems. Empedocles, however, besides his happy improvement on Parmenides, made a real contribution to thought when, as Aristotle puts it, he sought for a moving as well as for a material cause; in other words, when he asked not only of what elements the world is composed, but also by what forces were they brought together. He tells us of two such causes, Love and Strife, the one a combining, the other a dissociating power. If for these half-mythological names we read attractive and repulsive forces, the result will not be very different from our own current cosmologies. Such terms, when so used as to assume the existence of occult qualities in matter, driving its parts asunder or drawing them close together, are, in truth, as completely mythological as any figments of Hellenic fancy. Unlike their modern antitypes, the Empedoclean goddesses did not reign together, but succeeded one another in alternate dominion during protracted periods of time. The victory of Love was complete when all things had been drawn into a30 perfect sphere, evidently the absolute Eleatic Being subjected to a Heracleitean law of vicissitude and contradiction. For Strife lays hold on the consolidated orb, and by her disintegrating action gradually reduces it to a formless chaos, till, at the close of another world-period, the work of creation begins again. Yet growth and decay are so inextricably intertwined that Empedocles failed to keep up this ideal separation, and was compelled to admit the simultaneous activity of both powers in our everyday experience, so that Nature turns out to be composed of six elements instead of four, the mind which perceives it being constituted in a precisely similar manner. But Love, although on the whole victorious, can only gradually get the better of her retreating enemy, and Nature, as we know it, is the result of their continued conflict. Empedocles described the process of evolution, as he conceived it, in somewhat minute detail. Two points only are of much interest to us, his alleged anticipation of the Darwinian theory and his psychology. The former, such as it was, has occasionally been attributed to Lucretius, but the Roman poet most probably copied Epicurus, although the very brief summary of that philosopher��s physical system preserved by Diogenes Laertius contains no allusion to such a topic. We know, however, that in Aristotle��s time a theory identical with that of Lucretius was held by those who rejected teleological explanations of the world in general and of living organisms in particular. All sorts of animals were produced by spontaneous generation; only those survived which were accidentally furnished with appliances for procuring nourishment and for propagating their kind. The notion itself originated with Empedocles, whose fanciful suppositions have already been mentioned in a different connexion. Most assuredly he did not offer it as a solution of problems which in his time had not yet been mooted, but as an illustration of the confusion which prevailed when Love had only advanced a little way in her ordering, harmonising,31 unifying task. Prantl, writing a few years before the appearance of Mr. Darwin��s book on the Origin of Species, and therefore without any prejudice on the subject, observes with truth that this theory of Empedocles was deeply rooted in the mythological conceptions of the time.23 Perhaps he was seeking for a rationalistic explanation of the centaurs, minotaurs, hundred-handed giants, and so forth, in whose existence he had not, like Lucretius, learned completely to disbelieve. His strange supposition was afterwards freed from its worst extravagances; but even as stated in the De Rerum Natura, it has no claim whatever to rank as a serious hypothesis. Anything more unlike the Darwinian doctrine, according to which all existing species have been evolved from less highly-organized ancestors by the gradual accumulation of minute differences, it would be difficult to conceive. Every thinker of antiquity, with one exception, believed in the immutability of natural species. They had existed unchanged from all eternity, or had sprung up by spontaneous generation from the earth��s bosom in their present form. The solitary dissentient was Anaximander, who conjectured that man was descended from an aquatic animal.24 Strange to say, this lucky guess has not yet been quoted as an argument against the Ascidian pedigree. It is chiefly the enemies of Darwinism who are eager to find it anticipated in Empedocles or Lucretius. By a curious inversion of traditionalism, it is fancied that a modern discovery can be upset by showing that somebody said something of the kind more than two thousand years ago. Unfortunately authority has not the negative value of disproving the principles which it supports. We must be content to accept the truths brought to light by observation and reasoning, even at the risk of finding ourselves in humiliating agreement with a philosopher of antiquity.25