A little over 2,200 years ago, the Roman navy attacked the Greek port city of Syracuse. According to some ancient historians, the Greeks defended themselves with an ingenious weapon called a “burning mirror”: a polished copper surface curved to focus the Sun’s rays onto Roman ships, causing them to catch fire. However, we have several reasons to suspect that the story of the burning mirror is just a myth and the Greeks of Syracuse never really built such a device.
First, the ancient Greeks were not technologically advanced enough to make such a device. A mirror that would focus sunlight with sufficient intensity to set ships on fire would have to be several meters wide. Moreover, the mirror would have to have a very precise parabolic curvature (a curvature derived from a geometric shape known as the parabola). The technology for manufacturing a large sheet of copper with such specifications did not exist in the ancient world.
Second, the burning mirror would have taken a long time to set the ships on fire. In an experiment conducted to determine whether a burning mirror was feasible, a device concentrating the Sun’s rays on a wooden object 30 meters away took ten minutes to set the object on fire; and during that time, the object had to be unmoving. It is unlikely that Roman ships stayed perfectly still for that much time. Such a weapon would therefore have been very impractical and ineffective.
Third, a burning mirror does not seem like an improvement on a weapon that the Greeks already had: flaming arrows. Shooting at an enemy’s ships with flaming arrows was a common way of setting the ships on fire. The burning mirror and flaming arrows would have been effective at about the same distance. So the Greeks had no reason to build a weapon like a burning mirror.
Recently there has been a ton of debates as to the reality of the burning mirror weapon during the Greek Syracuse time. More specifically, regarding the passage, the writer puts forth the idea that the ancient Greeks had never used the burning mirror and this weapon is just a myth. In the listening passage, the lecturer is quick to point out there are some serious flaws in the writer's claims and address, in detail, the trouble with each point made in the reading text.
First and foremost, the author of the reading states that the ancient Greeks did not have a technology for building the burning mirror. Some professionals in the same field, however, stand infirm opposition to this claim. In the listening, for example, the professor states that the Greeks could utilize the small mirrors. She goes on to say that the Greek mathematicians were excellent enough to convert small mirrors to a parabolic burning mirrors.
One group of scholars, represented by the writer, think that the burning mirror was an ineffective weapon. Of course, though, not all experts in the field believe this is accurate. Again, the lecturer refutes this point when she says that woods were not the only materials of Roman ships, However, the Roman ships contained other materials can catch fire easily and quickly, such as Pitch which used as waterproof in the Roman ships.
Finally, the author wraps his argument by positing that the Greeks did not need the burning mirror as a weapon when they had the flaming arrows. Not surprisingly, the lecturer takes with this claim by contending that the Roman soldiers were familiar with the flaming arrows and they could see the arrows and prepare their defenses but they can not see burning rays from a mirror. Thus, the burning mirror could set a fire magically and suddenly at an unobserved place, resulting in a more effective attack than flaming arrows.
Grammar and spelling errors:
Line 5, column 443, Rule ID: A_PLURAL[2]
Message: Don't use indefinite articles with plural words. Did you mean 'mirror'?
Suggestion: mirror
...rt small mirrors to a parabolic burning mirrors. One group of scholars, represent...
^^^^^^^
Line 9, column 375, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...rials can catch fire easily and quickly, such as Pitch which used as waterproof i...
^^
Transition Words or Phrases used:
but, finally, first, however, if, regarding, so, thus, as to, for example, of course, such as
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 9.0 10.4613686534 86% => OK
Auxiliary verbs: 6.0 5.04856512141 119% => OK
Conjunction : 8.0 7.30242825607 110% => OK
Relative clauses : 11.0 12.0772626932 91% => OK
Pronoun: 20.0 22.412803532 89% => OK
Preposition: 33.0 30.3222958057 109% => OK
Nominalization: 2.0 5.01324503311 40% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1583.0 1373.03311258 115% => OK
No of words: 320.0 270.72406181 118% => OK
Chars per words: 4.946875 5.08290768461 97% => OK
Fourth root words length: 4.22948505376 4.04702891845 105% => OK
Word Length SD: 2.42330602883 2.5805825403 94% => OK
Unique words: 169.0 145.348785872 116% => OK
Unique words percentage: 0.528125 0.540411800872 98% => OK
syllable_count: 467.1 419.366225166 111% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 1.0 3.25607064018 31% => OK
Article: 10.0 8.23620309051 121% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 5.0 2.5761589404 194% => OK
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 24.0 21.2450331126 113% => OK
Sentence length SD: 52.0583423278 49.2860985944 106% => OK
Chars per sentence: 121.769230769 110.228320801 110% => OK
Words per sentence: 24.6153846154 21.698381199 113% => OK
Discourse Markers: 7.15384615385 7.06452816374 101% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 2.0 4.19205298013 48% => OK
Sentences with positive sentiment : 2.0 4.33554083885 46% => More positive sentences wanted.
Sentences with negative sentiment : 6.0 4.45695364238 135% => OK
Sentences with neutral sentiment: 5.0 4.27373068433 117% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.210720946642 0.272083759551 77% => OK
Sentence topic coherence: 0.0793317998719 0.0996497079465 80% => OK
Sentence topic coherence SD: 0.0424030884845 0.0662205650399 64% => OK
Paragraph topic coherence: 0.128210035692 0.162205337803 79% => OK
Paragraph topic coherence SD: 0.0290148083843 0.0443174109184 65% => OK
Essay readability:
automated_readability_index: 14.2 13.3589403974 106% => OK
flesch_reading_ease: 55.58 53.8541721854 103% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 11.5 11.0289183223 104% => OK
coleman_liau_index: 11.73 12.2367328918 96% => OK
dale_chall_readability_score: 8.08 8.42419426049 96% => OK
difficult_words: 66.0 63.6247240618 104% => OK
linsear_write_formula: 13.0 10.7273730684 121% => OK
gunning_fog: 11.6 10.498013245 110% => OK
text_standard: 12.0 11.2008830022 107% => OK
What are above readability scores?
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Rates: 83 out of 100
Scores by essay e-grader: 25 Out of 30
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Note: the e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.