Numbers
How Great Generals Win:
The 13 Rules of War from Ancient Greece to the War on Terror
History 361, Longwood University, Farmville, Virginia
The following are numbers that all educated persons should memorize. They will give you handles to make quick estimates of all sorts of things. Here are some examples. You can imagine an acre of ground as being a plot 220 x 200 feet or 44,000 square feet, only slightly more than the 43,560 square feet in an actual acre. You can plot the size of a suburban lot 100 x 150 feet = 15,000 square feet, or a bit larger than one-third of an acre. You can see in your mind the size of 210 acres by imagining a stretch of ground one mile long by one-third of a mile wide (or about one third of 640 acres, which is a square mile). You can convert kilometers per hour to approximate miles per hour by multiplying by .6.
A problem you can solve by logic: The top speed of human beings is about one mile in four minutes. This was the approximately speed that Roger Bannister achieved in May 1954. How fast is that in miles per hour? Using the same logic, what is the approximate top speed in miles per hour of a horse? Note that a Thoroughbred can cover a mile in 1.5 minutes. If you cannot figure these out by logic, send me a query by email, and I’ll show you the easy method.
- 5,280 feet in a mile
- 1,760 yards in a mile
- 1,609 meters in a mile
- 1.6093 kilometers (or approximately 1.6 km) in a mile
- Multiply kilometers by 0.62 (or approximately 0.6) to get miles
- 43,560 square feet in an acre
- 4,840 square yards in an acre
- 640 acres in a square mile
- hectare = one square hectometer = 100 meters x 100 meters = 10,000 square meters
- square kilometer = 100 hectares = 1,000,000 square meters
- 2.47 acres (or approximately 2.5 acres) in a hectare
- Multiply acres by 0.40 to get hectares
- In May 1954 an Englishman, Roger Bannister, ran the mile in just under four minutes; thus the approximate top sustained speed that a human can cover ground is a mile in four minutes.
- Although some persons can run faster, the approximate top human sprinting speed is 100 yards in 10 seconds.
- In the Shenandoah Valley campaign in the American Civil War, Stonewall Jackson’s main body of “foot cavalry” marched 18 miles on May 31, 1862, from Winchester to the outskirts of Strasburg; on the same day the Stonewall Brigade marched 35 miles from Harpers Ferry to four miles south of Winchester
- A Thoroughbred horse can run a mile (1.6 km) in 1.5 minutes
- The all-cavalry advance guard of the Mongol army under Subedei moved from the Ruske passes in the Carpathians to the Danube River at Buda-Pest, 180 miles, in three days, March 12-15, 1241, through enemy country deep in snow
- The Russian Federation has the largest land area of any country 6,592,000 square miles. Canada is second 3,851,000 sq mi. China is third 3,691,000 sq mi. The United States is fourth 3,615,000 sq mi. Brazil is fifth 3,286,000 sq mi. Australia is sixth 2,968,000 sq mi.
- According to the National Geographic Atlas of the World, Seventh Edition, 1999, China has the largest population of any country, 1.254 billion. India is second with 986 million. The United States is third with 271 million (passed 300 million in 2006). Indonesia is fourth with 212 million. Brazil is fifth with 168 million. The Russian Federation is sixth with 146.5 million (but Pakistan with only a few thousand fewer people in 1999 is certainly larger today). Mexico has 100 million people, Canada 30.6 million. Japan has 126 million, Germany 82 million, Britain 59.4 million, France 59 million, Italy 57.7 million.