An Introduction to the History of Science Part 2

If you glance at the study of mathematics, astronomy, and medicine among the Romans prior to the time of Greek influence, you find that next to nothing had been accomplished. Their method of field measurement was far less developed than the ancient Egyptian geometry, and even for it (as well as for their system of numerals) they were indebted to the Etruscans. The history of astronomy has nothing to record of scientific accomplishment on the part of the Romans. They reckoned time by months, and in the earlier period kept a rude tally of the years by driving nails into a statue of Ja.n.u.s, the ancient sun-G.o.d. As we shall see, they were unable to regulate the calendar. Again, so far were they from contributing to the development of medicine that they had no physicians for the six hundred years preceding the coming of Greek science. A medical slave acted as overseer of the family health, and disease was combated in primitive fas.h.i.+on by prayers and offerings to various G.o.ds, who were supposed to furnish general health or to influence the functions of the different parts of the body. So rude was the native culture of the Romans that it is doubtful whether they had any schools before the advent of Greek learning. The girls were trained by their mothers, the boys either by their fathers or by some master to whom they were apprenticed.

The Greeks were conquered by the Romans in 146 B.C., but before that time Roman life and inst.i.tutions had been touched by h.e.l.lenic culture.

Cato the Censor (who died in 149 B.C.) and other conservatives tried in vain to resist the invasion of Greek science, philosophy, and refinement. After the conquest of Greece the master became pupil, and the conqueror was taken captive. The Romans, however, never rose to preeminence in science or the fine arts. A further development in technology corresponded more closely to their national needs, and in this field they came undoubtedly to surpa.s.s the Greeks. Bridges, s.h.i.+ps, military roads, war-engines, aqueducts, public buildings, organization of the State and the army, the formulation of legal procedure, the enactment and codification of laws, were necessary to secure and maintain the Empire. The use in building construction of a knowledge of the right-angled triangle as well as other matters known to the Egyptians and Babylonians, and Archimedes' method of determining specific gravity were of peculiar interest to the practical Romans.

Julius Caesar, 102-44 B.C., inst.i.tuted a reform of the calendar. This was very much needed, as the Romans were eighty-five days out of their reckoning, and the date for the spring equinox, instead of coming at the proper time, was falling in the middle of winter. An Alexandrian astronomer (Sosigenes) a.s.sisted in establis.h.i.+ng the new (Julian) calendar. The principle followed was based on ancient Egyptian practice.

Among the 365 days of the year was to be inserted, or intercalated, every fourth year an extra day. This the Romans did by giving to two days in leap-year the same name; thus the sixth day before the first of March was repeated, and leap-year was known as a biss.e.xtile year. Caesar, trained himself in the Greek learning and known to his contemporaries as a writer on mathematics and astronomy, also planned a survey of the Empire, which was finally carried into execution by Augustus.

There is evidence that the need of technically trained men became more and more pressing as the Empire developed. At first there were no special teachers or schools. Later we find mention of teachers of architecture and mechanics. Then the State came to provide cla.s.srooms for technical instruction and to pay the salaries of the teachers.

Finally, in the fourth century A.D., further measures were adopted by the State. The Emperor Constantine writes to one of his officials: "We need as many engineers as possible. Since the supply is small, induce to begin this study youths of about eighteen years of age who are already acquainted with the sciences required in a general education. Relieve their parents from the payment of taxes, and furnish the students with ample means."

Pliny the Elder (23-79 A.D.), in the encyclopedic work which he compiled under the t.i.tle _Natural History_, drew freely on hundreds of Greek and Latin authors for his facts and fables. In the selection that he made from his sources can be traced, as in the work of Vitruvius and other Latin writers, the tendency to make the sciences subservient to the arts. For example, the one thousand species of plants of which he makes mention are considered from the medicinal or from the economic point of view. It was largely in the interest of their practical uses that the Roman regarded both plants and animals; his chief motive was not a disinterested love of truth. Pliny thought that each plant had its special virtue, and much of his botany is applied botany. So comprehensive a work as the _Natural History_ was sure to contain interesting antic.i.p.ations of modern science. Pliny held that the earth hovers in the heavens upheld by the air, that its sphericity is proved by the fact that the mast of a s.h.i.+p approaching the land is visible before the hull comes in sight. He also taught that there are inhabitants on the other side of the earth (antipodes), that at the time of the winter solstice the polar night must last for twenty-four hours, and that the moon plays a part in the production of the tides.

Nevertheless, the whole book is permeated by the idea that the purpose of nature is to minister to the needs of man.

It further marks the practical spirit among the Romans that a work on agriculture by a Carthaginian (Mago) was translated by order of the Senate. Cato (234-149 B.C.), so characteristically Roman in his genius, wrote (_De Re Rustica_) concerning grains and the cultivation of fruits.

Columella wrote treatises on agriculture and forestry. Among the technical writings of Varro besides the book on agriculture, which is extant, are numbered works on law, mensuration, and naval tactics.

It was but natural that at the time of the Roman Empire there should be great advances in medical science. A Roman's interest in a science was keen when it could be proved to have immediate bearing on practical life. The greatest physician of the time, however, was a Greek. Galen (131-201 A.D.), who counted himself a disciple of Hippocrates, began to practice at Rome at the age of thirty-three. He was the only experimental physiologist before the time of Harvey. He studied the vocal apparatus in the larynx, and understood the contraction and relaxation of the muscles, and, to a considerable extent, the motion of the blood through the heart, lungs, and other parts of the body. He was a vivisector, made sections of the brain in order to determine the functions of its parts, and severed the gustatory, optic, and auditory nerves with a similar end in view. His dissections were confined to the lower animals. Yet his works on human anatomy and physiology were authoritative for the subsequent thirteen centuries. It is difficult to say how much of the work and credit of this practical scientist is to be given to the race from which he sprang and how much to the social environment of his professional career. (In the ruins of Pompeii, destroyed in 79 A.D., have been recovered some two hundred kinds of surgical instrument, and in the later Empire certain departments of surgery developed to a degree not surpa.s.sed till the sixteenth century.) If it is too much to say that the Roman environment is responsible for Galen's achievements, we can at least say that it was characteristic of the Roman people to welcome such science as his, capable of demonstrating its utility.

Dioscorides was also a Greek who, long resident at Rome, applied his science in practice. He knew six hundred different plants, one hundred more than Theophrastus. The latter laid much stress, as we have seen in the preceding chapter, on the medicinal properties of plants, but in this respect he was outdone by Dioscorides (as well as by Pliny).

Theophrastus was the founder of the science of botany, Dioscorides the founder of materia medica.

Quintilian, born in Spain, spent the greater part of his life as a teacher of rhetoric in Rome. He valued the sciences, not on their own account, but as they might subserve the purposes of the orator. Music, astronomy, logic, and even theology, might be exploited as aids to public speech. In the time of Quintilian (first century A.D.), as in our own, oratory was considered one of the great factors in a young man's success; mock debating contests were frequent, and the periods of the future orators reverberated among the seven hills of Rome. To him our schools are also indebted for the method of teaching foreign languages by declensions, conjugations, vocabularies, formal rhetoric and annotations. He considered ethics the most valuable part of philosophy.

In fact, it would not be pressing our argument unduly to say that, so far as the minds of the Romans turned to speculation, it was the tendency to practical philosophy--Epicureanism or Stoicism--that was most characteristic. This was true even of Lucretius (98-55 B.C.), author of the n.o.ble poem concerning the Nature of Things (_De Rerum Natura_). In this work he writes under the inspiration of Greek philosophy. His model was a poem by Empedocles on Nature, the grand hexameters of which had fascinated the Roman poet. The distinctive feature of the work of Lucretius is the purpose, ethical rather than speculative, to curb the ambition, pa.s.sion, luxury of those hard pagan times, and likewise to free the souls of his countrymen from the fear of the G.o.ds and the fear of death, and to replace superst.i.tion by peace of mind and purity of heart.

From the work on Physical Science (_Quaestionum Naturalium, Libri Septem_) of Seneca, the tutor of Nero, we learn that the Romans made use of globes filled with water as magnifiers, employed hothouses in their highly developed horticulture, and observed the refraction of colors by the prism. At the same time the book contains interesting conjectures in reference to the relation of earthquakes and volcanoes, and to the fact that comets travel in fixed orbits. In the main, however, this work is an attempt to find a basis for ethics in natural phenomena. Seneca was a Stoic, as Lucretius was an Epicurean, moralist.

When we glance back at the culture, or cultures, of the great peoples of antiquity, Egyptian, Babylonian, Greek, and Roman, that which had its center on the banks of the Tiber offers the closest a.n.a.logy to our own.

Among English-speaking peoples as among the Romans there is noticeable a certain contempt for scientific studies strangely mingled with an inclination to exploit all theory in the interest of immediate application. An English author, writing in 1834, remarks that the Romans, eminent in war, in polite literature, and civil policy, showed at all times a remarkable indisposition to the pursuit of mathematical and physical science. Geometry and astronomy, so highly esteemed by the Greeks, were not merely disregarded by the Italians, but even considered beneath the attention of a man of good birth and liberal education; they were imagined to partake of a mechanical, and therefore servile, character. "The results were seen to be made use of by the mechanical artist, and the abstract principles were therefore supposed to be, as it were, contaminated by his touch. This unfortunate peculiarity in the taste of his countrymen is remarked by Cicero. And it may not be irrelevant to inquire, whether similar prejudices do not prevail to some extent even among ourselves." To Americans also must be attributed an impatience of theory as theory, and a predominant interest in the applications of science.

REFERENCES

Lucretius, _The Nature of Things_; translated by H. A. J. Munro.

Pliny, _Natural History_; translated by Philemon Holland.

Professor Baden Powell, _History of Natural Philosophy_.

Seneca, _Physical Science_; translated by John Clarke.

Vitruvius, _Architecture_; translated by Joseph Gwilt, 1826.

Vitruvius, _Architecture_; translated by Professor M. H. Morgan, 1914.

CHAPTER IV

THE CONTINUITY OF SCIENCE--THE MEDIEVAL CHURCH AND THE ARABS

Learning has very often and very aptly been compared to a torch pa.s.sed from hand to hand. By the written sign or spoken word it is transmitted from one person to another. Very little advance in culture could be made even by the greatest man of genius if he were dependent, for what knowledge he might acquire, merely on his own personal observation.

Indeed, it might be said that exceptional mental ability involves a power to absorb the ideas of others, and even that the most original people are those who are able to borrow the most freely.

In recalling the lives of certain great men we may at first be inclined to doubt this truth. How shall we account for the part played in the progress of civilization by the rustic Burns, the village-bred Shakespeare, or by Lincoln the frontiersman? When, however, we scrutinize the case of any one of these, we discover, of course, exceptional natural endowment, susceptibility to mental influence, remarkable powers of acquisition, but no ability to produce anything absolutely original. In the case of Lincoln, for example, we find that in his youth he was as distinguished by diligence in study as by physical stature and prowess. After he withdrew from school, he read, wrote, and ciphered (in the intervals of manual work) almost incessantly. He read everything he could lay hands on. He copied out what most appealed to him. A few books he read and re-read till he had almost memorized them. What const.i.tuted his library? The Bible, _aesop's Fables_, _Robinson Crusoe_, _The Pilgrim's Progress_, a _Life of Was.h.i.+ngton_, a _History of the United States_. These established for him a vital relation with the past, and laid the foundations of a democratic culture; not the culture of a Chesterfield, to be sure, but something immeasurably better, and none the less good for being almost universally accessible. Lincoln developed his logical powers conning the dictionary.

Long before he undertook the regular study of the law, he spent long hours poring over the revised statutes of the State in which he was living. From a book he mastered with a purpose the principles of grammar. In the same spirit he learned surveying, also by means of a book. There is no need to ignore any of the influences that told toward the development of this great statesman, the greatest of English-speaking orators, but it is evident that remote as was his habitation from all the famous centers of learning he was, nevertheless, early immersed in the current of the world's best thought.

Similarly, in the history of science, every great thinker has his intellectual pedigree. Aristotle was the pupil of Plato, Plato was the disciple of Socrates, and the latter's intellectual genealogy in turn can readily be traced to Thales, and beyond--to Egyptian priests and Babylonian astronomers.

The city of Alexandria, founded by the pupil of Aristotle in 332 B.C., succeeded Athens as the center of Greek culture. On the death of Alexander the Great, Egypt was ruled by one of his generals, Ptolemy, who a.s.sumed the t.i.tle of king. This monarch, though often engaged in war, found time to encourage learning, and drew to his capital scholars and philosophers from Greece and other countries. He wrote himself a history of Alexander's campaigns, and inst.i.tuted the famous library of Alexandria. This was greatly developed (and supplemented with schools of science and an observatory) by his son Ptolemy Philadelphus, a prince distinguished by his zeal in promoting the good of the human species. He collected vast numbers of ma.n.u.scripts, had strange animals brought from distant lands to Alexandria, and otherwise promoted scientific research.

This movement was continued under Ptolemy III (246-221 B.C.).

Something has already been said of the early astronomers and mathematicians of Alexandria. The scientific movement of the later Alexandrian period found its consummation in the geographer, astronomer, and mathematician Claudius Ptolemy (not to be confused with the rulers of that name). He was most active 127-151 A.D., and is best known by his work the _Syntaxis_, which summarized what was known in astronomy at that time. Ptolemy drew up a catalogue of 1080 stars based on the earlier work of Hipparchus. He followed that astronomer in teaching that the earth is the center of the movement of the heavenly bodies, and this geocentric system of the heavens became known as the Ptolemaic system of astronomy. To Hipparchus and Ptolemy we owe also the beginnings of the science of trigonometry. The _Syntaxis_ sets forth his method of drawing up a table of chords. For example, the side of a hexagon inscribed in a circle is equal to the radius, and is the chord of 60, or of the sixth part of the circle. The radius is divided into sixty equal parts, and these again divided and subdivided s.e.xagesimally. The smaller divisions and the subdivisions are known as prime minute parts and second minute parts (_partes minutae primae_ and _partes minutae secundae_), whence our terms "minute" and "second." The s.e.xagesimal method of dividing the circle and its parts was, as we have seen in the first chapter, of Babylonian origin.

Ptolemy was the last of the great Greek astronomers. In the fourth century and at the beginning of the fifth, Theon and his ill.u.s.trious daughter Hypatia commented on and taught the astronomy of Ptolemy. In the Greek schools of philosophy Plato's doctrine of the supreme reality of the invisible world was harmonized for a time with Christian mysticism, but these schools were suppressed at the beginning of the sixth century. The extinction of scientific and of all other learning seemed imminent.

What were the causes of this threatened break in the historical continuity of science? They were too many and too varied to admit of adequate statement here. From the latter part of the fourth century the Roman Empire had been overrun by the Visigoths, the Vandals, the Huns, the Ostrogoths, the Lombards, and other barbarians. Even before these incursions learning had suffered under the calamity of war. In the time of Julius Caesar the larger of the famous libraries of Alexandria, containing, it is computed, some 490,000 rolls, caught fire from s.h.i.+ps burning in the harbor, and perished. This alone involved an incalculable setback to the march of scientific thought.

Another influence tending to check the advance of the sciences was the clash between Christian and Pagan ideals. To many of the bishops of the Church the aims and pursuits of science seemed vain and trivial when compared with the preservation of purity of character or the a.s.surance of eternal felicity. Many were convinced that the end of the world was at hand, and strove to fix their thoughts solely on the world to come.

Their austere disregard of this life found some support in a n.o.ble teaching of the Stoic philosophy that death itself is no evil to the just man. The early Christian teachers held that the body should be mortified if it interfered with spiritual welfare. Disease is a punishment, or a discipline to be patiently borne. One should choose physical uncleanliness rather than run any risk of moral contamination.

It is not impossible for enlightened people at the present time to a.s.sume a tolerant att.i.tude toward the worldly Greeks or the other-worldly Christians. At that time, however, mutual antipathy was intense. The long and cruel war between science and Christian theology had begun.

Not all the Christian bishops, to be sure, took a hostile view of Greek learning. Some regarded the great philosophers as the allies of the Church. Some held that churchmen should study the wisdom of the Greeks in order the better to refute them. Others held that the investigation of truth was no longer necessary after mankind had received the revelation of the gospel. One of the ablest of the Church Fathers regretted his early education and said that it would have been better for him if he had never heard of Democritus. The Christian writer Lactantius asked shrewdly whence atoms came, and what proof there was of their existence. He also allowed himself to ridicule the idea of the antipodes, a topsy-turvy world of unimaginable disorder. In 389 A.D. one of the libraries at Alexandria was destroyed and its books were pillaged by the Christians. In 415 Hypatia, Greek philosopher and mathematician, was murdered by a Christian mob. In 642 the Arabs having pushed their conquest into northern Africa gained possession of Alexandria. The cause of learning seemed finally and irrecoverably lost.

The Arab conquerors, however, showed themselves singularly hospitable to the culture of the nations over which they had gained control. Since the time of Alexander there had been many Greek settlers in the larger cities of Syria and Persia, and here learning had been maintained in the schools of the Jews and of a sect of Christians (Nestorians), who were particularly active as educators from the fifth century to the eleventh.

The princ.i.p.al Greek works on science had been translated into Syrian.

Hindu arithmetic and astronomy had found their way into Persia. By the ninth century all these sources of scientific knowledge had been appropriated by the Arabs. Some fanatics among them, to be sure, held that one book, the Koran, was of itself sufficient to insure the well-being of the whole human race, but happily a more enlightened view prevailed.

In the time of Harun Al-Ras.h.i.+d (800 A.D.), and his son, the Caliphate of Bagdad was the center of Arab science. Mathematics and astronomy were especially cultivated; an observatory was established; and the work of translation was systematically carried on by a sort of inst.i.tute of translators, who rendered the writings of Aristotle, Hippocrates, Galen, Euclid, Ptolemy, and other Greek scientists, into Arabic. The names of the great Arab astronomers and mathematicians are not popularly known to us; their influence is greater than their fame. One of them describes the method pursued by him in the ninth century in taking measure of the circ.u.mference of the earth. A second developed a trigonometry of sines to replace the Ptolemaic trigonometry of chords. A third made use of the so-called Arabic (really Hindu) system of numerals, and wrote the first work on Algebra under that name. In this the writer did not aim at the mental discipline of students, but sought to confine himself to what is easiest and most useful in calculation, "such as men constantly require in cases of inheritance, legacies, part.i.tion, law-suits, and trade, and in all their dealings with one another, or where the measuring of lands, the digging of ca.n.a.ls, geometrical computation, and other objects of various sorts and kinds are concerned."

In the following centuries Arab inst.i.tutions of higher learning were widely distributed and the flood-tide of Arab science was borne farther west. At Cairo about the close of the tenth century the first accurate records of eclipses were made, and tables were constructed of the motions of the sun, moon, and planets. Here as elsewhere the Arabs displayed ingenuity in the making of scientific apparatus, celestial globes, s.e.xtants of large size, quadrants of various sorts, and contrivances from which in the course of time were developed modern surveying instruments for measuring horizontal and vertical angles.

Before the end of the eleventh century an Arab born at Cordova, the capital of Moorish Spain, constructed the Toletan Tables. These were followed in 1252 by the publication of the Alphonsine Tables, an event which astronomers regard as marking the dawn of European science.

Physics and chemistry, as well as mathematics and astronomy, owe much in their development to the Arabs. An Arabian scientist of the eleventh century studied the phenomena of the reflection and refraction of light, explained the causes of morning and evening twilight, understood the magnifying power of lenses and the anatomy of the human eye. Our use of the terms retina, cornea, and vitreous humor may be traced to the translation of his work on optics. The Arabs also made fair approximations to the correct specific weights of gold, copper, mercury, and lead. Their alchemy was closely a.s.sociated with metallurgy, the making of alloys and amalgams, and the handicrafts of the goldsmiths and silversmiths. The alchemists sought to discover processes whereby one metal might be trans.m.u.ted into another. Sulphur affected the color and substance. Mercury was supposed to play an important part in metal trans.m.u.tations. They thought, for example, that tin contained more mercury than lead, and that the baser, more unhealthy metal might be converted into the n.o.bler and more healthy by the addition of mercury.

They even sought for a substance that might effect all trans.m.u.tations, and be for mankind a cure for all ailments, even that of growing old.

The writings that have been attributed to Geber show the advances that chemistry made through the experiments of the Arabs. They produced sulphuric and nitric acids, and _aqua regia_, able to dissolve gold, the king of metals. They could make use of wet methods, and form metallic salts such as silver nitrate. Laboratory processes like distilling, filtering, crystallization, sublimation, became known to the Europeans through them. They obtained potash from wine lees, soda from sea-plants, and from quicksilver the mercuric oxide which played so interesting a part in the later history of chemistry.

Much of the science lore of the Arabs arose from their extensive trade, and in the practice of medicine. They introduced sugar-cane into Europe, improved the methods of manufacturing paper, discovered a method of obtaining alcohol, knew the uses of gypsum and of white a.r.s.enic, were expert in pharmacy and learned in materia medica. They are sometimes credited with introducing to the West the knowledge of the mariner's compa.s.s and of gunpowder.

Avicenna (980-1037), the Arab physician, not only wrote a large work on medicine (the _Canon_) based on the lore of Galen, which was used as a text-book for centuries in the universities of Europe, but wrote commentaries on all the works of Aristotle. For Averroes (1126-1198), the Arab physician and philosopher, was reserved the t.i.tle "The Commentator," due to his devotion to the works of the Greek biologist and philosopher. It was through the commentaries of Averroes that Aristotelian science became known in Europe during the Middle Ages. In his view Aristotle was the founder and perfecter of science; yet he showed an independent knowledge of physics and chemistry, and wrote on astronomy and medicine as well as philosophy. He set forth the facts in reference to natural phenomena purely in the interests of the truth. He could not conceive of anything being created from nothing. At the same time he taught that G.o.d is the essence, the eternal cause, of progress.

It is in humanity that intellect most clearly reveals itself, but there is a transcendent intellect beyond, union with which is the highest bliss of the individual soul. With the death of the Commentator the culture of liberal science among the Arabs came to an end, but his influence (and through him that of Aristotle) was perpetuated in all the western centers of education.

The preservation of the ancient learning had not, however, depended solely on the Arabs. At the beginning of the sixth century, before the taking of Alexandria by the followers of Mohammed, St. Benedict had founded the monastery of Monte Ca.s.sino in Italy. Here was begun the copying of ma.n.u.scripts, and the preparation of compendiums treating of grammar, dialectic, rhetoric, arithmetic, astronomy, music, and geometry. These were based on ancient, Roman writings. Works like Pliny's _Natural History_, the encyclopedia of the Middle Ages, had survived all the wars by which Rome had been devastated. Learning, which in Rome's darkest days had found refuge in Britain and Ireland, returned book in hand. Charlemagne (800) called Alcuin from York to instruct princes and n.o.bles at the Frankish court. At this same palace school half a century later the Irishman Scotus Erigena exhibited his learning, wit, and logical ac.u.men. In the tenth century Gerbert (Pope Sylvester II) learned mathematics at Arab schools in Spain. The translation of Arab works on science into the Latin language, freer intercourse of European peoples with the East through war and trade, economic prosperity, the liberation of serfs and the development of a well-to-do middle cla.s.s, the voyages of Marco Polo to the Orient, the founding of universities, the encouragement of learning by the Emperor Frederick II, the study of logic by the schoolmen, were all indicative of a new era in the history of scientific thought.

The learned Dominican Albertus Magnus (1193-1280) was a careful student of Aristotle as well as of his Arabian commentators. In his many books on natural history he of course pays great deference to the Philosopher, but he is not devoid of original observation. As the official visitor of his order he had traveled through the greater part of Germany on foot, and with a keen eye for natural phenomena was able to enrich botany and zoology by much accurate information. His intimacy with the details of natural history made him suspected by the ignorant of the practice of magical arts.