The term mouse fly is kind of a contradiction and one of the types of flies that brings the word fly in fly fishing almost as far away from something flying as possible - still surpassed by shrimp flies not to mention crab flies, but anyway...
One of the reasons Britain became rich was because the Industrial Revolution (factories and such) got off the ground there sooner. Britain had a large navy, and many colonies in other parts of the world, such as India, and Rhodesia.
Best Answer: The biggest reason was that Britain started the Industrial Revolution earlier than other countries. Because they had newer technology, they could sell it to other countries to make money, and also use it to conquer other places.