a history of science-1-第39章
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greed radically as to what functions certain organs performed； and how diseases should be treated； even when agreeing perfectly on the subject of anatomy itself。 Their contribution to the knowledge of the scientific treatment of diseases holds no such place； therefore； as their anatomical investigations。 Half a century after the time of Herophilus there appeared a Greek physician； Heraclides； whose reputation in the use of drugs far surpasses that of the anatomists of the Alexandrian school。 His reputation has been handed down through the centuries as that of a physician； rather than a surgeon； although in his own time he was considered one of the great surgeons of the period。 Heraclides belonged to the 〃Empiric〃 school； which rejected anatomy as useless； depending entirely on the use of drugs。 He is thought to have been the first physician to point out the value of opium in certain painful diseases。 His prescription of this drug for certain cases of 〃sleeplessness； spasm； cholera； and colic；〃 shows that his use of it was not unlike that of the modern physician in certain cases； and his treatment of fevers； by keeping the patient's head cool and facilitating the secretions of the body； is still recognized as 〃good practice。〃 He advocated a free use of liquids in quenching the fever patient's thirsta recognized therapeutic measure to…day； but one that was widely condemned a century ago。
ARCHIMEDES OF SYRACUSE AND THE FOUNDATION OF MECHANICS We do not know just when Euclid died； but as he was at the height of his fame in the time of Ptolemy I。； whose reign ended in the year 285 B。C。； it is hardly probable that he was still living when a young man named Archimedes came to Alexandria to study。 Archimedes was born in the Greek colony of Syracuse； on the island of Sicily； in the year 287 B。C。 When he visited Alexandria he probably found Apollonius of Perga； the pupil of Euclid； at the head of the mathematical school there。 Just how long Archimedes remained at Alexandria is not known。 When he had satisfied his curiosity or completed his studies； he returned to Syracuse and spent his life there； chiefly under the patronage of King Hiero； who seems fully to have appreciated his abilities。 Archimedes was primarily a mathematician。 Left to his own devices； he would probably have devoted his entire time to the study of geometrical problems。 But King Hiero had discovered that his protege had wonderful mechanical ingenuity； and he made good use of this discovery。 Under stress of the king's urgings； the philosopher was led to invent a great variety of mechanical contrivances； some of them most curious ones。 Antiquity credited him with the invention of more than forty machines； and it is these； rather than his purely mathematical discoveries； that gave his name popular vogue both among his contemporaries and with posterity。 Every one has heard of the screw of Archimedes； through which the paradoxical effect was produced of making water seem to flow up hill。 The best idea of this curious mechanism is obtained if one will take in hand an ordinary corkscrew； and imagine this instrument to be changed into a hollow tube； retaining precisely the same shape but increased to some feet in length and to a proportionate diameter。 If one will hold the corkscrew in a slanting direction and turn it slowly to the right； supposing that the point dips up a portion of water each time it revolves； one can in imagination follow the flow of that portion of water from spiral to spiral； the water always running downward； of course； yet paradoxically being lifted higher and higher towards the base of the corkscrew； until finally it pours out （in the actual Archimedes' tube） at the top。 There is another form of the screw in which a revolving spiral blade operates within a cylinder； but the principle is precisely the same。 With either form water may be lifted； by the mere turning of the screw； to any desired height。 The ingenious mechanism excited the wonder of the contemporaries of Archimedes； as well it might。 More efficient devices have superseded it in modern times； but it still excites the admiration of all who examine it； and its effects seem as paradoxical as ever。 Some other of the mechanisms of Archimedes have been made known to successive generations of readers through the pages of Polybius and Plutarch。 These are the devices through which Archimedes aided King Hiero to ward off the attacks of the Roman general Marcellus； who in the course of the second Punic war laid siege to Syracuse。 Plutarch； in his life of Marcellus； describes the Roman's attack and Archimedes' defence in much detail。 Incidentally he tells us also how Archimedes came to make the devices that rendered the siege so famous： 〃Marcellus himself； with threescore galleys of five rowers at every bank； well armed and full of all sorts of artillery and fireworks； did assault by sea； and rowed hard to the wall； having made a great engine and device of battery； upon eight galleys chained together； to batter the wall： trusting in the great multitude of his engines of battery； and to all such other necessary provision as he had for wars； as also in his own reputation。 But Archimedes made light account of all his devices； as indeed they were nothing comparable to the engines himself had invented。 This inventive art to frame instruments and engines （which are called mechanical； or organical； so highly commended and esteemed of all sorts of people） was first set forth by Architas； and by Eudoxus： partly to beautify a little the science of geometry by this fineness； and partly to prove and confirm by material examples and sensible instruments； certain geometrical conclusions； where of a man cannot find out the conceivable demonstrations by enforced reasons and proofs。 As that conclusion which instructeth one to search out two lines mean proportional； which cannot be proved by reason demonstrative； and yet notwithstanding is a principle and an accepted ground for many things which are contained in the art of portraiture。 Both of them have fashioned it to the workmanship of certain instruments； called mesolabes or mesographs； which serve to find these mean lines proportional； by drawing certain curve lines； and overthwart and oblique sections。 But after that Plato was offended with them； and maintained against them； that they did utterly corrupt and disgrace； the worthiness and excellence of geometry； making it to descend from things not comprehensible and without body； unto things sensible and material； and to bring it to a palpable substance； where the vile and base handiwork of man is to be employed： since that time； I say； handicraft； or the art of engines； came to be separated from geometry； and being long time despised by the philosophers； it came to be one of the warlike arts。 〃But Archimedes having told King Hiero； his kinsman and friend； that it was possible to remove as great a weight as he would； with as little strength as he listed to put to it： and boasting himself thus （as they report of him） and trusting to the force of his reasons； wherewith he proved this conclusion； that if there were another globe of earth； he was able to remove this of ours； and pass it over to the other： King Hiero wondering to hear him； required him to put his device in execution； and to make him see by experience； some great or heavy weight removed； by little force。 So Archimedes caught hold with a book of one of the greatest carects； or hulks of the king （that to draw it to the shore out of the water required a marvellous number of people to go about it； and was hardly to be done so） and put a great number of men more into her； than her ordinary burden： and he himself sitting alone at his ease far off； without any straining at all； drawing the end of an engine with many wheels and pulleys； fair and softly with his hand； made it come as gently and smoothly to him； as it had floated in the sea。 The king wondering to see the sight； and knowing by proof the greatness of his art； be prayed him to make him some engines； both to assault and defend； in all manner of sieges and assaults。 So Archimedes made him many engines； but King Hiero never occupied any of them； because he reigned the most part of his time in peace without an
