Science in the Classical age was as fixed as was the society, it was stratified - the top strata was pure, it was mathematics and geometry taken to its highest form, it was science taken to the realm of philosophy. Plato had envisioned a fixed, mathematical realm of perfect forms that superseded the physical realm of imperfection. This second or impure realm was comparable to the area of the artisan, the craftsman, the builder or even scientist that did practical experimentation. And what set Hellenistic age apart from the Classical age, in science, crosscurrents and intermingling of ideas, the willingness individuals to look at life differently and philosophers: Theophrastus and Strato who fully immersed themselves into study of nature or physics as it was known to the ancients, thus becoming the first scientists of the Hellenistic era. It must be pointed out that most men of learning, like Plato and Aristotle, during the Classical age, disdained the practical side.
And even with the condescension, great strides were made in certain areas of science: in mathematics, astronomy, medicine and technology. This paper will examine the accomplishments of the different areas of the sciences, technology, and look at the great names of antiquity, and present the gulf, between the pure, theoretical side of science versus the practical side.
To begin this examination we must first look, briefly, at the the classical period, it was not as fixed, it was not a mathematically ordered. With the arrival of Philip and the Alexander the balance of power shifted from Athens, to Macedon and, then, with Alexander's generals fighting for power after his death, the power and center of the Greek world shifted to Alexandria, Pergamum and Macedonia.
And though there was a broader spectrum of ideas floating across this Hellenized, Mediterranean world, the society, as was most of the ancient world, was static in the sense that there wasn't an advancement of humanity. And as Peter Green points out, this lack of movement was reflected by the philosophical view that permeated the era - monadism - viewing the universe as a living organism, that did not evolve, and within this living universe, which was mathematically ordered, the earth was placed at its center. (454) Since this society wasn't moving there was certainly no need for a push for labor saving devices. There was not an ordered search for the new nor make the society better nor was there an ethos to find ways to make society better.
Slavery and an extremely cheap labor force was the largest element within this firmly rooted civilization. Since labor was cheap and abundant, the idea of cultural evolution was irrelevant. And whatever movement that did exist was only at the top ranks of the society, the plays for power of its rulers. Though there was a push for scientific advancement and this came from the rulers, like the Ptolemies and the Attalids, who used the science or technology to gratify their power and their prestige. This patronage set up three areas for the advancement of technology: the military, for exciting patron in temples and to beautify cities.
Before examining the technological accomplishment of the Hellenistic era we will first look at the scientists. The first step will be going to Athens, the home of Classical science. The difference between Hellenistic science and Classical science can be best illustrated by looking at the first scientist of the Hellenistic era.
Theophrastus, the successor to Aristotle, it can be said was the first scientist of the Hellenistic age. Theophrastus is important for he lays a foundation for observation: "Nature, he tells us, is more multifarious and disorderly and its study depends on the evidence of the sense." (160 Farrington) And more importantly he is the first of the scientists that breaks away from the ideal of the "First Principle." "First principles are definite and unchanging as being concerned with objects of reason, without motion or change." (Ibid) According to Benjamen Farrington Theophrastus was not satisfied with the status quo and he questioned whether there was such a thing as the "First Principle." Theophrastus went further and postulated that mathematics was not an intrinsic part of nature but rather was a human creation when looking at nature. And departing from the view that everything was mathematically interconnected made Theophrastus indeed the first Hellenistic scientist.
The most important contribution that Theophrastus made, to the applied sciences, was the division he observed between plants and animals.(164 Farrington) Breaking from the traditional view (held by both Plato and Aristotle) that life was a form of degeneration - animals were derived from human or man, and plants devolved from animals. Farrington reported that Aristotle, in his lack of drawing a distinction between the differences of plants and animals, created the opportunity for Theophrastus to observe those differences, and that he did. In his book History of Plants he clarified the differences by stating that with animals there was a permanence, and with plants there was a temporalness to them, as in annual renewal of the leaf, flower or fruit.(165 Farr) But his classifications went well beyond illustrating the superficial difference between plants and animals. Theophrastus classified plants into trees, shrubs, undershrubs, and herbs. He went further by setting up more striking classifications of wild versus cultivated, aquatic or terrestrial, those that bear fruit and those -hat do not, .lowering and those don't flower, deciduous or evergreen.(52 Clagett)
An area where Theophrastus agreed and then broke from Aristotle's view was that of spontaneous generation. Aristotle believed that occasionally plants could spontaneously generate. From his perspective plants or trees manifested for no apparent reason. Theophrastus agreed wit h reservations, he did not rule out the possibility that wind carried seeds that germinated in the ground
Farrington goes on to remark that Theophrastus' contribution, of recognizing the differences of plants and animals and classifying them, would not be matched in the field of botany until the modern age.(166 Farr)
The cornerstone of science is the systematic repetitive methods of research, this basically did not exist in the ancient world, but, the rudiments of experimentation did manifest in the works of Strato.
Strato was the successor to Theophrastus. He, for some time, lived at the King's palace at Alexandria and tutored his son Philadelphus, and then went to Athens and became the head of the Lyceum. Strato had forsaken the study of ethics and concentrated on studying nature and thus became known as "The Physicist." Both Polybius and Cicero mocked Strato for this heresy. Polybius wrote that Strato was good when he commented on the works of others but when he was original he was stupid.(Polybius, book XII sec. 25 c) this mocking of Strato was not an isolated incident, as was mentioned at the outset of this paper, the split between the correct study of science or philosophy versus the lesser branches, permeated all of antiquity. Strato himself called the study of nature the oldest of the philosophies, and he said that Socrates turned from the study of nature to the study of man.(172 Farr)
Farrington relays the finding of a manuscript by a preeminent scientist Hermann Diels in the late nineteenth century. Diels translated this s work that was .from the works or Hero of Alexandria. The opening pages describes the nature of a vacuum.
It was quite advanced and Diels wrote that Hiero was describing the work of Strato. In the work Strato describes, ,n depth, the nature of the vacuum, and this he arrives at by describing experimentation that was virtually foreign to the ancients, experimentation that was not to have arrived on the scene until the Renaissance.(177 Farr) Strato's work is full, of examples of experimentation to answer some of his scientific problems. For example:
"It is pointed out that if heat is applied to coal so as to produce coke, the coke appears to the eye to be of the same bulk as the coal but is found on weighing to be lighter. Here again is evidence of the exact measurement of phenomena. The loss of weight is ascribed to the transformation of coal under the action of fire into three substances of differing densities, classed as fire, air, and earth.(179 Farr)
It must be noted that the author that presented the above quote reported that scientific measurement like this did not occur until the beginning of the seventeenth century.
Strato had other important physical discoveries, Marshall Clagett relates that Strato's work also pertained to movement and weight. One work entitled On Motion Strato takes the rudimentary theory that Aristotle postulated on acceleration further (though still rudimentary compared with the knowledge on physics that exists today.) Aristotle observed that when an item travels, or is propelled, it is the force that is creating the acceleration. Strato took this view and expanded it by looking at the space and time that the object was traveling through.(70 Clag)
Strato also broke away from Aristotle's view on weight or gravity. Aristotle postulated that there were two tendencies in the nature on objects, one, that heavy objects are pulled towards the center of the earth, and two, lighter ones are pulled away .from it, (the lighter objects were fire and air.) Strato believed that there was not two tendencies but one, that actually the second tendency was being acted upon by the first.(15 Lloyd)
The key elements with Strato were observation and experimentation, this is important factor of breaking away from the classical period in science. The pattern that these Hellenistic scientists were setting broke apart from the status quo by questioning, observing and experimenting. The next individuals that will be discussed will be the two most outstanding astronomers: Aristarchus of Samos and Eratosthenes of Cyrene.
Aristarchus is very important, because he also breaks from the classical mode, for postulating a heliocentric theory. What made the heliocentric theory - the view that the earth revolved around the sun - so revolutionary was that the existing classical theory, as was mentioned, was a mathematical model that placed the earth in a fixed position with the stars and planets revolving around it. And as history has shown us, most theories that displaced the common held, narrow perspective died an incredibly slow death. And apparently, even in the face of bold new facts or knowledge most of the scientists and or philosophers abandoned the new information and stuck with the old to uphold their theories.
G.E.R. Lloyd said that the extant body of work Of Aristarchus mentions nothing of a heliocentric theory. What we do know of his theory, came via the mathematician Archimedes. In the introduction of Archimedes' work The SandReckoner he wrote:
Aristarchus of Samos brought out a book of certain hypotheses, in which it follows from what is assumed that the universe is many times greater than that now so called. He hypothesizes that the fixed stars and the sun remain unmoved; that the earth is borne round the sun on the circumference of a circle...; and that the sphere of the fixed stars, situated about the same center as the sun, is so great that the circle in which he hypothesizes that the earth revolves bears such a proportion that the distance of the fixed stars as the center of the sphere does to its surface. (Lloyd p.54)
To translate this passage, as best possible from a layman's point of view, is to remark that Aristarchus expanded on the theoretical size of the universe and interjected a rotating earth encircling a fixed sun and stars.
Aristarchus, it was reported by Plutarch, was attacked by Cleanthes the stoic, with "impiety for putting in motion the Hearth of the Universe, this being the effect of his attempt to rest and the earth to revolve in oblique circle, while it rotates, on its axis."(Clagett 91) And thus we see the conflict within the Hellenistic age as someone put forth a new idea; he was certainly attacked for attempting to disrupt the status quo. Aristarchus' vision was so bold and insightful that Marshall Clagett went so far as to not only call Aristarchus the Copernicus of the ancient world but called Copernicus the Aristarchus of the modern era.(92)
Lloyd also reprints the attack by Cleanthes but takes why the heliocentric theory wasn't adapted further by stating the number of reasons: one, the religious view as held by Cleanthes, two, if the earth is moving then why aren't items, like clouds or missiles, moving through the air affected? And three, other Hellenist c astronomers questioned why there was not an apparent stellar parallax (parallax view is when looking at something through a substance like water and it appears bent, a straight stick seems crooked.) Ancient scientists wondered why when looking at stars and planets from different locations there was no variation, they always looked the same. If the earth is rotating why wouldn't there be variations? But the lack of a stellar parallax also comes into play with a geocentric view as well. The point is the' to the ancients it was easier to postulate moving heavens than a moving earth. And there's also the psychological aspect that correlated to their world view, basically it was stationary, their world was the center of the universe.
Eratosthenes was a Hellenistic scientist whose star shown very brightly. He was so talented that he was called "Beta" which meant second. He was second best to every scientist in every field, he wasn't just the best in one field, he was second in every field. He was so versatile that he called himself Philogos meaning one who is in love with learning.(179 Davis) He was a writer as well' as the librarian at the museum at Alexandria.
Eratosthenes' accomplishments were many but the most outstanding feat was measuring the earth's circumference. Harold T. Davis reports that Eratosthenes' method of measuring the earth's circumference has not changed since his day.(183 Davis) And as Davis writes:
"He observed that at Syene at the time of summer solstice no shadow fell into a well at noontime, a fact so curious that it must have been commented on buy travelers. This meant, of course, that Syene was directly under the Tropic of Cancer, or at least, nearly so. At the same time Eratosthenes measured at Alexandria the shadow of the gnomon, -an astronomical instrument like the vertical triangular plate of a sundial, - in order to determine the latitude. This he found to be one fiftieth of a circle." (183 DAVIS)
Eratosthenes then took the distance between Syene and Alexandria, approximately 5,000 stadia and multiplied by 50 and arrived at the estimated circumference of the earth - 250,000 stadia. minis translating into modern miles, depending on whose measurement of the stadium one takes, is either 24,662 miles or 29,000 miles, either way it was extremely close.
Eratosthenes not only came up with the circumference of the earth but also laid the foundation for geographical measurements. As opposed to modern Greenwich, he chose Alexandria as the Prime meridian of the Hellenistic world. The line he created divided east from west, and it followed the course of the Nile and went as far south as the known world, the land of the Nubians, and passed through Alexandria and up through the Euxine sea to the mouth of the Borysthenes river. (185 Davis) For a parallel line Eratosthenes chose Rhodes as his meridian and extended it east to the base of Tarsus mountains and west through the boot of Italy and on to the strait of Columns (Gibralter)(Ibid.) Davis states that Eratosthenes' measurements were close yet incorrect. (Ibid) But the most important aspect of his measurements was the concept that the earth was round. Davis relays a quotation from Strabo which states:
"Again, attempting still further to appease us by saying that it is ~in accordance with nature to call the distance from east to west greater, he says it is in accordance with nature that from the east to the west the inhabited world is forger, and, just as I have already stated in the manner of the mathematicians,' he says, 'it forms a complete circle, itself meeting itself; so that, if the immensity of the Atlantic Sea did not prevent, we could sail from Iberia to India along one and the same parallel over the remainder of the circle."' (185 Davis)
And so what this shows is a theory that the earth was round some eighteen hundred years prior to Columbus's journey. Eratosthenes was just one of man of brilliant scientists that existed in the Hellenistic period.
And thus so far the pattern that is developing is that though the foundation of thought in the Hellenistic world was fixed there was movement on the top layers, in politics and more importantly for this paper, in the sciences. The elements of this movement were: questioning the mathematical certainty of life, observing the universe around them and postulating new ideas. And as we have seen there were many new ideas. The next area that will be addressed are medicine.
The scientific methods used for medicine were pretty feeble in the ancient world. The state of health and disease was connected to magic. They prayed to their gods for health, to heal, for most things, and they used strange herbs like the mandrake. But there were individuals that broke the pattern of superstition and one such person, that stood out for his scientific approach was a man named Herophilus.
Herophilus, a contemporary of Euclid's, was brought to Alexandria from Chalcedon. His observations of the body were direct and not approximations. Herophilus' account of the brain was in depth, he described what tendons and nerves were, and he especially described how nerves functioned. He also made an observation of the eye and his descriptions of the retina and optic nerve were impressive. Herophilus made a detailed study of the vascular system and he differentiated between arteries and veins. And, Herophilus used a water-clock in measuring the pulse, which Davis relates that Herophilus was quite remarkable in his analysis.(171 Davis)
Herophilus also came up with a general theory on what ran the body. He said that the body was divided by four forces that directed it: heating in the heart, perceiving in the nerves, nourishing in the liver, and thinking in the brain. Besides an in depth observation of the body Herophilus also used drugs that were effective in healing.(ibid) Davis also relays that Herophilus 'us' work: on obstetrics was studied for centuries afterward. And, what Lloyd said about Herophilus comes across that he was quite advanced beyond his predecessors, he wrote:
"That he was able to dissect human cadavers seems likely. At any rate, we are told that he left detailed descriptions of the various systems-nervous, vascular, digestive, and osseous. Particularly noteworthy was his description of the brain, in which the cerebrum, was distinguished from the cerebellum." (41 Lloyd)
Erasistratus, the successor to Herophilus, also had a more scientific approach to medicine. He stressed hygiene as very important in connection to health. And he was against blood-letting and the use of drugs in healing.(172 Davis) He continued in the work of safely describing the anatomy and physiology of the body. Erasistratus also formulated how the epiglottis stopped food from entering the windpipe when eating.(Clagett 41) He was known for postulating a mechanical theory of the operations of the body. Erasistratus described the peristaltic action of food travelling aloes the alimentary canal by muscular motion. His theory contradicted Aristotle's view that food broke down in the stomach by an "innate heat."(80 Lloyd) He put forth the idea of food breaking down and being transformed into a substance that passed through the stomach walls and into the intestines.
One note that needs to be made is that ever though there were great strides made by individuals like Erasistatus and Herophilus, they still had some strange beliefs (or beliefs that corresponded to their times.) Erasistratus postulated a theory of pneuma (life force) that coursed through the veins, and when a vein is cut a vacuum is created and blood pushes the pneuma out. Marshall Clagett remarked that Erasistratus more than likely borrowed this idea from Strato.(41 Clagett) And Lloyd says of Eristratus that he was quite outstanding in his approach to medicine and yet he put worth some wild conjecture. He, Erisistratus, postulated two types of pneumas, one that was a 'vital spirit' which was situated in the was the prime mover of the nervous system and is located in the brain.(84 Lloyd)
One other note is that Thomas W. Africa reprints what Celsus, a Roman medical writer, wrote about both Herophilus and Erasistratus. Celsus was convinced that they were given criminals for vivisection. There is controversy on whether it was true. But as Africa noted with the inhumanity that went on within the concentration camps of Nazi Germany it probably is not out of the realm of possibility, or probability that they did practice vivisection.(52 Africa)
Two areas that are very important in the realm of science are mathematics and technology. In mathematics three names jump out of the Hellenistic age - Euclid, Archimedes and Apollonius.
What we know of Euclid came through the writings of Proclus, a fifth century A.D. writer.(Lloyd 34) Euclid lived at the time of the first Ptolemy around 300 B.C.. With Euclid came not an innovator but rather a synthesizer. His "elements" of geometry replaced the elements that were created by mathematicians of the Classical age, Eudoxus and .Theaetetus most notably. The "elements" are basic aspects of geometry that other aspects of propositions are arrived from. There are thirteen books of Euclid's elements; and within these books are plane geometry, the nature and properties of whole numbers, solid geometry and the theory of proportions and magnitudes.
It consists, rather, in the way the whole work is put together. The "elements" is a highly systematic work."(Lloyd 36) An example of Euclid's synthesizing is his use of a Pythagorean theorem which states that the square on the hypotenuse of a right-angled triangle is equal to the sum of the squares on the other two sides. Throughout Euclid's work it is apparent that geometrical theorems are taken from earlier mathematicians, and thus Euclid was the great synthesizer.
The second name is probably the greatest name n mathematics of the ancient world, and that name is Archimedes. His works include: On the Sphere and the Cylinder, On the Measurement of a Circle, On Conoids and Spheroids, On Floating Bodies, On the Quadrature of the Parabola, On the Method, The Sandreckoner, On Spirals, and On the Equilibrium of Planes.(60 Clagget) Most of Archimedes work is concerned with finding the areas and volumes of curved surfaces and solids. And with those areas and volumes he compared them to areas of different angles such as triangles, rectangles and or cubes. The foundation of Archimedes' discovery of the areas was his procedures of reduction to absurdity along with his method of exhaustion, (it must be pointed out the the precise translations or understanding of theories or formulas of either mathematics, physics or any branch of science that contains theorems can only be approximations since the level of comprehension of mathematics of the author of this paper is pretty low so to go into describing what the reduction to absurdity is absurd.) The bottom line with Archimedes was that he successfully demonstrated theorems for the surfaces and volumes of different spaces.
The most important contribution Archimedes made, mathematics, was dispensing the fear of using large numbers. Greeks used alphabetical symbols when computing large numbers in arithmetic. As today we use ten symbols they used 27, and they did use mathematical notation, and this would make computing large numbers very difficult if not impossible. In the book the SandReckoner Archimedes compares the universe to grains of sand, and if the number of grains of sand were known then it could have been expressed.(Farr 212) Farrington states that the number that Archimedes could express is equal in our notation as 1 followed by eighty thousand million million zeros.(Ibid.)
In discussing Archimedes one must not just look at his mathematics but rather look at the whole picture. Archimedes lived some twenty to forty years after Euclid, and he was from Syracuse. The most outstanding aspects of his like, at Syracuse, were his engineering feats, the weapons he created in fighting the Romans, stories about him, and his death.
His death was important because he was killed while working on a theorem, he had been so preoccupied that he didn't even know that the Romans had invaded the island, and then a soldier broke in and killed him. Another story has him figuring out, for King Hiero, if a crown was made of 100% gold. Hiero was worried that the artist that made the crown diluted it by adding silver.
Archimedes realized how to do the experiment when he immersed himself in a bath and noticed the water seeping over the sides of the tub. He immediately got up out of the tub and ran through the streets of Syracuse, yelling "Eureka."(47 Lloyd) The idea that came to him was to find out what the weight of the crown was, i. it was pure gold. He took a piece of gold and piece of silver and placed each one in a container of water and observed the overflow, he then could determine the purity of the crown by observing its overflow and comparing to both the overflows of the gold and silver.
Archimedes' incredible feats of engineering were many and Plutarch writes of how Archimedes had stated to Hiero that he could move any weight by the slightest force, and this is what Plutarch describes:
"Archimedes chose for his demonstration a three-masted merchantman of the royal fleet, which had been hauledashore with immense labour by a large gang of men, and he proceeded to have the ship loaded with her usual freight and embarked a large number of passengers. He then seated himself at some distance away and without using any noticeable force, but merely exerting traction with his hand through a complex system of pulleys, he drew the vessel towards him with as smooth and even a motion as if she were gliding through the water."(Plutarch P99)
Plutarch goes on to describe how the potential for creating engines of war had deeply impressed Hiero. And when the Romans attacked Syracuse they were, at first, held at bay, until they figured out how to get past Archimedes' ingenuity. In the following paragraph Plutarch relays how Arhimedes' inventions disrupted and frightened the Roman army:
"presently Archimedes brought his engines to bear andlaunched a tremerdous barrage against the Roman army. This consisted of a variety of .missiles, including a great volley of stones which descended upon their target with an incredible noise and velocity. there was no protection against this artillery, and the soldiers were knocked down in swathes and their ranks thrown into confusion. At the same time huge beams were run out from the walls so as to project over the Roman ships: some of them were then sunk by great weights dropped from above, while others were seized at the bows by iron claws or by beaks like those of cranes, hauled into the air by means of counterweights..."(100 Plutarch)
For a page and a half more Plutarch describes how Archimedes' ingenuity stopped the Romans from invading Syracuse. And it has to be remembered, as Plutarch wrote, whatever achievement or invention that Archimedes created was insignificant to him because he thought they were a by-product of his study of geometry. (this belief system of Arhimedes' will be touched on shortly.)
With the discussion of Archimedes' engines of war it will lead us into the topic of technology. Farrington says of Arcnimedes that he was not just the greases' mathematician but probably the greatest engineer of the ancient world. Just some of his inventions of note were: a planetarium, a screw for raising water for irrigatlng and for raising water in mines, the movement of great weights by pulleys, the military engines used in protecting Syracuse, and Archimedes was also known for his puzzles comparable to the modern rubies cube.(Farr p. 214)
As Green states "Warfare elicited some of the most striking instances of applied science in the Hellenistic period, in writers also relate that there were a number of inventions: a pump, a water-clock and improvements on the catapult.(100 Lloyd)
There was a gulf between the theoretical and practical side of science although there were great strides and discoveries. Peter Green intensely declares that the gulf was so great that a real scientific age did not exist. And most of the accomplishments, he writes, were matched or surpassed by the Classical philophers or Pythagoreans, and yet P.M. Fraser maintains that the level of accomplishments, in the Hellenistic era, had reached a zenith that would no. be matched until the seventeenth century of the modern era. In fact Fraser writes:
"In spite of these 'imitations a sufficiency of facts emerges from our sources to enable us to state with some confidence that in some vital respects the medical achievement of Alexandria, especially in the third century B.C., reached a level never achieved before, or indeed again until the seventeenth certury. In medicine, as in mathematics and scholarship, what lies between Ptolemaic Alexandria and the modern world represents a retrogression from the A'exandrian performance."(341 Fraser)
Though Green does admit that certain scientists' work would not be matched until the renaissance, however, his basic view is that arrogance, religious beliefs and a static society prevented a climate for a true scientific culture from flourishing.
G.E.R. Lloyd talks o the theoretical,/practical demarcation ot the sciences and his view was not as striking as that of Green's. Lloyd mentions that when Plutarch discussed how much Archimedes disdained engineering Plutarch's word was not to be trusted, in fact, he goes so far as to say that Pluatrch may have frabricated the information about Archimedes.(95 Lloyd) Plutarch, engineering experience and was influenced by Platonism that regarded the baunistic as inferior.(Lloyd 95) The point is that we cannot truly know what Archimedes felt about engineering. But we do know that there was a split .
There is one other point in discussing Hellenistic science and that was the difference between Egyption and Greek science. P.M. Fraser remarks that Egyption science or rather Egyption mathematics was much more practical, it was not purely theoretical. Egyptian mathematics dealt with "land measurement, irrigation, and building"(400 Fraser) where Greek science was concerned with the theoretical. And thus what arrives with this point is that the Hellenistic age was different that of the Classical age. In the Classical age there was one location, Athens, and this was the center of the universe. But in the Hellenistic age there were a number of locations, such as Alexandria and Persamum as centers, that were different from Athens and had different influences on the science that was practiced.
Overall a scientific world did not exist, a scientific world comparable with what we have today. As that is looking at something in a scientific way, observing the world or observing an experiment and recording the results. This ethos didn't exist but as we have seen a number of the scientists did follow modern, scientific methods and were, indeed, ahead of their time. The question arises that if a society is not directing itself towards becoming a community based on scientific principles does that mean that individuals within the society aren't scientists? The answer is no, they are scientists and those like Theostratus, Strato and Aristarchus, to name a few made observations and recorded their results of their experiments and they made great discoveries that wouldn't be matched for almost nineteen hundred years.