At the time when Carneades delivered his lectures, the morality of Rome resembled that of Sparta during her great conflict with Athens, as characterised by one of the speakers in the Melian Dialogue. Scrupulously honourable in their dealings with one another, in their dealings with foreign nations her citizens notoriously identified justice with what was agreeable or advantageous to themselves. The arguments of the Academic philosopher must, therefore, have been doubly annoying to the leaders of the State, as a satire on its public policy and as a source of danger to the integrity of its private life. In this respect, old Cato was a type of the whole race. In all transactions with his fellow-citizens, and in every office undertaken on behalf of the community, his honesty was such that it became proverbial. But his absolute disregard of international justice has become equally proverbial through the famous advice, reiterated on every possible occasion, that an unoffending and unwarlike city should be destroyed, lest its existence should at some future time become a source of uneasiness to the mistress of the world. Perhaps it was a secret consciousness of his own inconsistency which prevented him from directly proposing that Carneades should not be allowed to continue his lectures. At any rate, the ex-Censor contented himself with moving that the business on which the Athenian envoys had come should be at once concluded, that they might return to their classes at Athens, leaving the youth of Rome to seek instruction as before from the wise conversation and example of her public men.214 We are not told whether his speech on this occasion wound up with the usual formula, caeterum, Patres Conscripti, sententia mea est Carthaginem esse delendam; but as it is stated that from the year 175 to the end of his life, he never made a motion in the Senate that was not terminated by those words, we are entitled to assume that he did not omit them in the present instance. If so, the effect must have been singularly grotesque; although, perhaps, less so than if attention had been drawn to the customary phrase by its unexpected absence. At any rate, Carneades had an opportunity of carrying back one more illustration of ethical inconsistency wherewith to enliven his lectures on the vanity of dogmatising and the absolute equilibrium of contradictory opinions.Designing, or generating the plans of machinery, may be considered the leading element in engineering manufactures or machine construction, that one to which all others are subordinate, [75] both in order and importance, and is that branch to which engineering knowledge is especially directed. Designing should consist, first, in assuming certain results, and, secondly, in conceiving of mechanical agents to produce these results. It comprehends the geometry of movements, the disposition and arrangement of material, the endurance of wearing surfaces, adjustments, symmetry; in short, all the conditions of machine operation and machine construction. This subject will be again treated of at more length in another section.
ONE:In adding another to the large number of books which treat upon Mechanics, and especially of that class devoted to what is called Mechanical Engineering, it will be proper to explain some of the reasons for preparing the present work; and as these explanations will constitute a part of the work itself, and be directed to a subject of some interest to a learner, they are included in the Introduction.
ONE:If the nature of their errand was not precisely calculated to win respect for the profession of the Athenian envoys, the subsequent proceedings of one among their number proved still less likely to raise it in the estimation of those whose favour they sought to win. Hellenic culture was, at that time, rapidly gaining ground among the Roman aristocracy; Carneades, who already enjoyed an immense reputation for eloquence and ingenuity among his own countrymen, used the opportunity offered by his temporary residence in the imperial city to deliver public lectures on morality; and such was the eagerness to listen that for a time the young nobles could think and talk of nothing else. The subject chosen was justice. The first lecture recapitulated whatever had been said in praise of that virtue by Plato and Aristotle. But it was a principle of the sect to which Carneades belonged that every affirmative proposition, however strongly supported, might be denied with equal plausibility. Accordingly, his second discourse was entirely devoted to upsetting the conclusions advocated in the first. Transporting the whole question, as would seem, from a private to a public point of view, he attempted to show, from the different standards prevailing in different countries, that there was no such thing as an immutable rule of right; and also that the greatest and most successful States had profited most by unscrupulous aggressions on their weaker neighbourshis most telling illustrations being drawn from the history of the Romans themselves. Then, descending once more to private life, the sceptical lecturer expatiated on the frequency of those cases in which justice is opposed to self-interest, and the folly of122 sacrificing ones own advantage to that of another. Suppose a good man has a runaway slave or an unhealthy house to sell, will he inform the buyer of their deficiencies, or will he conceal them? In the one case he will be a fool, in the other case he will be unjust. Again, justice forbids us to take away the life or property of another. But in a shipwreck, will not the just man try to save his life at anothers expense by seizing the plank of which some weaker person than himself has got holdespecially if they are alone on the sea together? If he is wise he will do so, for to act otherwise would be to sacrifice his life. So also, in flying before the enemy, will he not dispossess a wounded comrade of his horse, in order to mount and escape on it himself? Here, again, justice is incompatible with self-preservationthat is to say, with wisdom123!213Lawrence came in puffing one of his eternal cigarettes. His manner was full of confidence.
THREE:But if Aristotle had not his masters enthusiasm for practical reforms, nor his masters command of all the forces by which humanity is raised to a higher life, he had, more even than his master, the Greek passion for knowledge as such, apart from its utilitarian applications, and embracing in its vast orb the lowliest things with the loftiest, the most fragmentary glimpses and the largest revelations of truth. He demanded nothing but the materials for generalisation, and there was nothing from which he could not generalise. There was a place for everything within the limits of his world-wide system. Never in any human soul did the309 theorising passion burn with so clear and bright and pure a flame. Under its inspiration his style more than once breaks into a strain of sublime, though simple and rugged eloquence. Speaking of that eternal thought which, according to him, constitutes the divine essence, he exclaims:
Jeff paid no attention to Larrys natural anger and wonder."But are you sure? Where are the French now, and where did the British land?"A principle in mechanics may be known, and even familiar to a learner, without being logically understood; it might even be said that both theory and practice may be learned without the power to connect and apply the two things. A person may, for example, understand the geometry of tooth gearing and how to lay out teeth of the proper form for various kinds of wheels, how to proportion and arrange the spokes, rims, hubs, and so on; he may also understand the practical application of wheels as a means of varying or transmitting motion, but between this knowledge and a complete wheel lies a long train of intricate processes, such as pattern-making, moulding, casting, boring, and fitting. Farther on comes other conditions connected with the operation of wheels, such as adaptation, wear, noise, accidental strains, with many other things equally as important, as epicycloidal curves or other geometrical problems relating to wheels.60
