THREE: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 sizea 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.1. The steam-engine is an agent for utilising the power of heat and applying it to useful purposes.
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THREE:The division of matter into minute and indestructible particles served admirably to account for the gradual formation and disappearance of bodies without necessitating the help of a creator. But the infinities assumed as a condition of atomism were of even greater importance. Where time and space are unlimited, the quantity of matter must be equally unlimited, otherwise, being composed of loose particles, it would long since have been dissipated and lost in the83 surrounding void. Now, given infinite time and space, and infinite atoms capable of combining with one another in various ways, all possible combinations must already have been tried, not once or twice, but infinitely often. Of such combinations, that which best fulfils the conditions of mechanical stability will last the longest, and, without being designed, will present all the characters of design. And this, according to Epicurus, is how the actual frame of things comes to be what it is. Nor was it only the world as a whole that he explained by the theory of a single happy accident occurring after a multitude of fortuitous experiments. The same process repeats itself on a smaller scale in the production of particular compounds. All sorts of living bodies were originally throw up from the earths bosom, but many of them instantly perished, not being provided with the means of nutrition, propagation, or self-defence. In like manner we are enabled to recall a particular thought at pleasure, because innumerable images are continually passing through the mind, none of which comes into the foreground of consciousness until attention is fixed on it; though how we come to distinguish it from the rest is not explained. So also, only those societies survived and became civilised where contracts were faithfully observed. All kinds of wild beasts have at different times been employed in war, just as horses and elephants are now, but on trial were found unmanageable and given up.162
THREE:"Well, I borrowed the original and had a copy made," Lawrence confessed. "You see I was bound to have a copy, as I am going to return the little bottle as soon as I have more or less verified its history. Now I want you to get away after dinner and come as far as my chambers to meet Bruce."It was well over at length, but the mild little cashier had nothing to say except that he really must go over to the Raven's Arms and have a little brandy. Abstemious man as he was, he felt it was necessary. Presently the blood came back to his face again, and his dilated pupils contracted.
THREE:At the other end of the bridge I was left by my escort, and went on alone; on my left the Meuse, on my right burning houses, above me hissing and whistling shells, that came down in front of me and behind me, with tremendous explosions, throwing the loose earth high into the air.