According to this document, what are two ways that steam engines helped the economy in Great Britain?

..Every great town has one or more slum areas into which the working classes are packed. Sometimes, of course, poverty is to be found hidden away in alleys close to the stately homes of the wealthy. Generally, however, the workers are segregated in separate districts where they struggle through life as best they can out of of sight of the more fortunate classes of society. The slums of the English towns have much in common--the worst houses in a town being found in the worst districts. They are generally unplanned wildernesses of one- or two-stored terrace houses built of brick. Wherever possible these have cellars which are also used as dwellings. These little houses of three or four rooms and a kitchen are called cottages, and throughout England, except for some parts of London, are where the working classes normally live. The streets themselves are usually unpaved and full of holes. They are filthy and strewn with animal and vegetable refuse. Since they have neither gutters nor drains the refuse accumulates in stagnant, stinking puddles. Ventilation in the slums is inadequate owing to the hopelessly unplanned nature of these areas. A great many people live huddled together in a very small area, and so it is easy to imagine the nature of the air in these workers' quarters. However, in fine weather the streets are used for the dying of washing and clothes lines are stretched across the streets from house to house and wet garments are hung out on them...

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