The main purpose of Anna Sewell's writing of her novel Black Beauty was to bring public attention to the cruel practice in Victorian times of the restrictive "bearing rein" which forced horses' heads upward in a "proud" posture. This bearing rein prohibited horses from putting their heads down as they naturally would if they stumbled or if they were pulling a carriage uphill; in other words, the bearing rein threw horses off balance at times and strained them as they could not throw their weight into efforts as they would naturally be able without it. In Chapter 11, Beauty's master talks with Captain Langley, a friend who believes in the bearing rein, objecting to this usage,
"You may depend upon it, horses were intended to have their heads free, as free as men's are; and if we would act a little more according to common sense, and a good deal less according to shion, we should find many things work easier."
Other cruel practices such as the cutting off of horses' tails affected balance, too; in addition, it prohibited horses from being able to swish away flies or other insects. The vanities of the upper class Victorians are further depicted as, for instance, Beauty is sold after his legs are scarred from a fall after the drunken Reuben Smith takes him on a dangerous ride. This incident also points to the Victorian emphasis on temperance.
Sewell addressed other issues, as well, such as the financial harships caused London horse-drawn cab drivers as they paid high fees, but were prohibited from raising rates. Thus, the horses were underfed and overworked. Also, she drew attention to the inhumane treatment of draft horses who were overburdened and beaten if they could not pull the heavy loads.
The Victorian emphasis on temperance, the work ethic, and Christian values is certainly depicted in the story of the London cab driver, Jerry Barker, who works hard and does not drink and takes good care of Beauty. Furthermore, his kind heart leads him to take a friend to the country and visit family. While there, Beauty gets to graze in a pasture.
thank you very much for your swift and detailed response