“There’s always hacks about in packs, Wherein you may be shaken, And Jarvis is not always _drunk_, Tho’ always _overtaken_; In racing tricks he’ll never mix, His nags are in their last days, And slow to go, altho’ they show As if they had their _fast days_! “Then if you like a single horse, This age is quite a _cab-age_, A car not quite so small and light As those of our Queen _Mab_ age; The horses have been _broken well_, All danger is rescinded, For some have _broken both their knees_, And some are _broken-winded_.” While these cabs were still running, several experiments were being made with patent carriages. One of these, placed on the streets for a short while, was the invention of Mr. William Boulnois. “It was a two-wheeled closed vehicle,” says Mr. Moore, “constructed to carry two passengers sitting face to face. The driver sat on a small and particularly unsafe seat on the top of it, and the door was at the back. It was, in fact, so much like the front of an omnibus that it was well known as the _omnibus slice_. Its popular name was the _back-door cab_. Superior people called it a _minibus_. This cab was quickly followed by a very similar, although larger, vehicle invented by Mr. Harvey. It was called a _duobus_.” These two cabs cannot have been very comfortable; the shafts were too short, and the knowledge that a possibly heavy coachman was sitting just above your head seems to have militated against their success.