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.
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.
Firstly, 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.
Secondly, 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.
Thirdly, 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.
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Transition Words or Phrases used:
first, firstly, however, if, moreover, really, second, secondly, so, still, therefore, third, thirdly
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 : 4.0 7.30242825607 55% => More conjunction wanted.
Relative clauses : 6.0 12.0772626932 50% => More relative clauses wanted.
Pronoun: 10.0 22.412803532 45% => OK
Preposition: 39.0 30.3222958057 129% => OK
Nominalization: 3.0 5.01324503311 60% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1514.0 1373.03311258 110% => OK
No of words: 308.0 270.72406181 114% => OK
Chars per words: 4.91558441558 5.08290768461 97% => OK
Fourth root words length: 4.18926351222 4.04702891845 104% => OK
Word Length SD: 2.62777694477 2.5805825403 102% => OK
Unique words: 164.0 145.348785872 113% => OK
Unique words percentage: 0.532467532468 0.540411800872 99% => OK
syllable_count: 472.5 419.366225166 113% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 12.0 8.23620309051 146% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 2.0 1.51434878587 132% => OK
Preposition: 2.0 2.5761589404 78% => OK
Performance on sentences:
How many sentences: 15.0 13.0662251656 115% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 52.8063969189 49.2860985944 107% => OK
Chars per sentence: 100.933333333 110.228320801 92% => OK
Words per sentence: 20.5333333333 21.698381199 95% => OK
Discourse Markers: 6.73333333333 7.06452816374 95% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 2.0 4.33554083885 46% => More positive sentences wanted.
Sentences with negative sentiment : 11.0 4.45695364238 247% => Less negative sentences wanted.
Sentences with neutral sentiment: 2.0 4.27373068433 47% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.389827464933 0.272083759551 143% => OK
Sentence topic coherence: 0.12992951445 0.0996497079465 130% => OK
Sentence topic coherence SD: 0.147859858192 0.0662205650399 223% => The coherence between sentences is low.
Paragraph topic coherence: 0.257164320062 0.162205337803 159% => OK
Paragraph topic coherence SD: 0.2394393646 0.0443174109184 540% => More connections among paragraphs wanted.
Essay readability:
automated_readability_index: 12.0 13.3589403974 90% => Automated_readability_index is low.
flesch_reading_ease: 59.64 53.8541721854 111% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 9.9 11.0289183223 90% => OK
coleman_liau_index: 11.26 12.2367328918 92% => OK
dale_chall_readability_score: 8.11 8.42419426049 96% => OK
difficult_words: 68.0 63.6247240618 107% => OK
linsear_write_formula: 9.0 10.7273730684 84% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 10.0 11.2008830022 89% => OK
What are above readability scores?
---------------------
Rates: 60.0 out of 100
Scores by essay e-grader: 18.0 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.