ONE:Under certain conditions a given quantity of soft iron or steel may be cut away at less expense, and with greater accuracy, by milling than by any other process.These are but a few of many influences which tend to irregular cooling, and are described with a view of giving a clue from which other causes may be traced out. The want of uniformity in sections which tends to irregular cooling can often be avoided without much loss by a disposition of the metal with reference to cooling strains. This, so far as the extra metal required to give uniformity to or to balance the different sides of a casting, is a waste which engineers are sometimes loth to consent to, and often neglect in designs for moulded parts; yet, as before said, the difficulty of irregular cooling can in a great degree be counteracted by a proper distribution of the metal, without wasting, if the matter is properly understood. No one is prepared to make designs for castings who has not studied the subject of cooling strains as thoroughly as possible, from practical examples as well as by theoretical deductions.
ONE:It is not, then, surprising that the Academic and Peripatetic schools utterly failed to carry on the great movement inaugurated by their respective founders. The successors of Plato first lost themselves in a labyrinth of Pythagorean mysticism, and then sank into the position of mere moral instructors. The history of that remarkable revolution by which the Academy regained a foremost place in Greek thought, will form the subject of a future chapter: here we may anticipate so far as to observe that it was effected by taking up and presenting in its original purity a tradition of older date than Platonism, though presented under a new aspect and mixed with other elements by Plato. The heirs of Aristotle, after staggering on a few paces under the immense burden of his encyclopaedic bequest, came to a dead halt, and contented themselves with keeping the treasure safe until the time should arrive for its appropriation and reinvestment by a stronger speculative race.
ONE:"I know--I mean, what do I mean?" the Countess said hoarsely. "Really I don't know why I should be so interested."The effect of tempering baths is as their conducting power; chemicals except as they may contribute to the conducting properties of a bath, may safely be disregarded. For baths, cold or ice water loaded with salt for extreme hardness, and warm oil for tools that are thin and do not require to be very hard, are the two extremes outside of which nothing is required in ordinary practice.
