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Show 90 WATER-~TEAM. find a cause preventing them, those crystals always assume the same form. The formation of the crystals is ohe motion, and it is a very important one; because as there is no other substance which crystallizes under exactly the same circumstances as common salt, it is by knowing and bringing about that small and invisible motion that we are enabled to give a pure and wholesome reli~h to our ~ood i. for even common salt, as it exists m nature, IS nuxed with magnesia and sulphur, and other ingredients which render it unpalatable and unw~olesome .. The previous state of the pro~ess IS a1s<? motwn. A certain quantity of water, hav1~g a certam degree of heat, is necessary for separatn~g ~h~ natural salt into particles so smal~ as to be. mvi~I?le ; and t~e quantity that can be dissolved m b01hng water IS far greater than that which can be dissolved in col~ water. Now it is the property of water that It be a-ins to boil at two hundred degrees of the common th~rmometer or a little less or more according to the state of the atmosphere. When that is ligh~, boiling water is a little cooler; ~n~ when hea.vr, 1t is a little warmer: but the vanatwns are tnflmg, and not necessary to be taken into account in common observation, though we cannot observe even the operations of na~ure to pr.oper advantage without knowing somethmg of theu causes. When the water comes to the boiling point, if the surface of it is freely exposed to the air, it never becomes any hotter; and after i~ fairly. boils, one could not warm it one jot, except It were m a closed vessel, even though it were exposed to a fire of the greatest strength for twelv.e mon~hs. And the w~t~r contends for this law of Its bemg, even when It IS in small quantity, with strength far excetding the strength of armies. It is t~~ resis.tance ?f water to beina- heated above the b01lmg pomt which has enabled England to add the steam-engine to tbe implemeut: s of her labour ; and thus leave the horses .. APPLICATION OF STEAM. 91 to the plough and the team, and man to superintend and to observe, and thence to learn and to do, more and more for his own enjoyment, and the improvement of his country and his kind. The people who lived two centuries ago, and who were as wise and observ::~nt in their generation as we are, would have thought the teller mad if they had been told, that independently of their downward motion to the sea, which turns the mill and carries the barge as they glide, there slumbers in the streams an active power -a source of motion, not only greater than that of all the men and all the horses and other animals in England, but greater than the expertest penman in the world could set down by arithmetical contrivance, though he sat ciphering his whole life. And the beauty of the matter is, that this mighty power, which is in the posse~sion of everybody that has a pitcher of water, is, with proper machinery and skilful management, not only more governable than the highest bred horse, but more gentle than any lamb that ever sported in the meadow. At the same time, it could, if need were, bring the power of ten millions of horses to bear on a single point; and were it to answer any purpose, if man could find the rna. chinery, this simple property of water would give the power of cleaving the earth in twain. But, notwithstanding it can spin a thread finer than gossamer, and weave it into gauze which will float in the air like a vapour ; it will grind at the mill, toil in the manufactory, and it will print a book; and the people of England enjoy now ten times the comforts eP~oyed by their fathers, and disperse a portion of those comforts to all the nations of the world, and receive the produce of all climates in return, just because a skilful observer of nature discovered I that water reststs being heated above two hundred and twelve degrees. One would think that only a trifling discovery; and if the little fact were told without any of the consequences, nobody would give a far- |
