Sewell wrote Black Beauty in a time when the usage of horses was a major issue undergoing a huge transformation. She was writing in the context of 19th century England. For centuries, humans of England had used horses in nearly every aspect of societal life. Humans would make use of horses in transportation, like the cab drivers and carriages of the book, and in warfare, like old Captain the warhorse as well as in agriculture, construction and the myriad of other activities necessary for a society to function. All that was changing though in the time Sewell wrote her book; the steam engine and other new technological advances were rapidly fulfilling the functions horses and other animals alone had previously fulfilled. With the invention of the steam engine, railway transportation quickly overtook horse carriage in long-distance journeys. It would be a while more before engines replaced carriages in short-term travel as well, but the trend towards technologically treated inevitably on. So through her book the reader gets a glimpse of a disappearing world, a world where one can see coal horses dragging carts, and horse carriages instead of cars and war horses charging into battle with their riders.
Much of this change had such a large attraction to people because of the massive logistical issues surrounding the upkeep of horses. In 19th century England, London lay at the center of this problem. Estimates suggest that in that capital city were about 300,000 horses serving all kinds of functions. This huge number of horses all had to be fed, sheltered, cleaned and looked after. The usage of horses in London thus perpetuated a logistical nightmare for the city. The horses’ waste alone required a network of street cleaners and haulers and even with this network, waste still remained in the city and caused deadly health problems on a significant scale. The city as a whole was not the only entity that bore the cost of these horses; each individual horse owner had to expend significant amounts of money to maintain the horse. They of course had to be cared for, and their equipment had to be bought, cleaned and maintained. Their owners also had to hire grooms and coachmen. All together the cost of maintaining a horse in 19th century London was more than the cost of maintaining a car today.
Beyond these logistical concerns there were also legal ramifications of this extensive usage of horses. Cruelty towards horses was a huge worry; horses had a significant role in labor as work animals, and this position sometimes incentivized their exploitation and abuse. The first English law on the matter was the Treat of Horses Bill of 1821. This required prosecution for those who beat their horses. Although a step forward in terms of animal rights, the law did not cover the other forms of exploitation and was, in any case, difficult to enforce. In order to increase the effectiveness of this law, a group formed the Society for the Prevention of Cruelty to Animals. This group acted as an almost grassroots watchdog collective, inspecting coachmen and cab drivers and making sure no one was getting away with beating their horses. Twenty years later the group became a Royal Society by order of Queen Victoria. Perhaps the tall gentleman mentioned in chapter 38 is a member of this very same group.