Answer:
British mathematician William Bourne made some of the earliest known plans for a submarine around 1578, but the world’s first working prototype was built in the 17th century by Cornelius Drebbel, a Dutch polymath and inventor in the employ of the British King James I. Drebbel’s sub was probably a modified rowboat coated in greased leather and manned by a team of oarsmen. Sometime around 1620, he used it to dive 15 feet beneath the River Thames during a demonstration witnessed by King James and thousands of astonished Londoners. Unfortunately, none of Drebbel’s plans or engineering drawings has survived to today, so historians can only guess about how his “diving boat” actually operated. Some accounts say it submerged via a collection of bladders or wooden ballast tanks, while others suggest that a sloping bow and a system of weights were used to propel the boat underwater when it was rowed at full speed.
Explanation:
Invasions by Barbarian tribes. ...
Economic troubles and overreliance on slave labor. ...
The rise of the Eastern Empire. ...
The most important reason for the collapse of Rome was the failure to actually integrate what they conquered. When Roman soldiers conquered new lands, it was rare that they ever attempted to force their culture, ideals, or laws upon the natives and barbarians. Thus, when the Empire began suffering internal struggles, the natives they had conquered decided to take action, which lead to the swift collapse by barbarian invasion from all sides. It's hard to pick a LEAST important reason, seeing that there were many of them, but I suppose a contender would most likely be the common refusal of the Empire to even acknowledge that barbarians were rising. On the outer edges of their territory, in places like Gaul and Morocco, the Roman government was reluctant to even recognize the threat of the barbarians, thinking that even accepting that these barbarians were causing trouble would weaken their prestige in the public eye.
Answer:
Gold rush and mining opportunities (silver in Nevada)
The opportunity to work in the cattle industry; to be a “cowboy”
Faster travel to the West by railroad; availability of supplies due to the railroad.Explanation:
It was the "Nile River" that contributed most to trade in the new kingdom in Egypt, since this river allowed both for the cultivated of numerous crops through increased irrigation, as well as the transport of goods along the river.
