In the following year, Bell became professor of Vocal Physiology and Elocution at the Boston University School of Oratory. During this period, he alternated between Boston and Brantford, spending summers in his Canadian home. At Boston University, Bell was "swept up" by the excitement engendered by the many scientists and inventors residing in the city. He continued his research in sound and endeavored to find a way to transmit musical notes and articulate speech, but although absorbed by his experiments, he found it difficult to devote enough time to experimentation. While days and evenings were occupied by his teaching and private classes, Bell began to stay awake late into the night, running experiment after experiment in rented facilities at his boarding house. Keeping "night owl" hours, he worried that his work would be discovered and took great pains to lock up his notebooks and laboratory equipment. Bell had a specially made table where he could place his notes and equipment inside a locking cover. Worse still, his health deteriorated as he suffered severe headaches. Returning to Boston in fall 1873, Bell made a fateful decision to concentrate on his experiments in sound.
What was Bell's discipline?
Vocal Physiology and Elocution

The empire went into decline thereafter. The Mughals suffered several blows due to invasions from Marathas and Afghans. During the decline of the Mughal Empire, several smaller states rose to fill the power vacuum and themselves were contributing factors to the decline. In 1737, the Maratha general Bajirao of the Maratha Empire invaded and plundered Delhi. Under the general Amir Khan Umrao Al Udat, the Mughal Emperor sent 8,000 troops to drive away the 5,000 Maratha cavalry soldiers. Baji Rao, however, easily routed the novice Mughal general and the rest of the imperial Mughal army fled. In 1737, in the final defeat of Mughal Empire, the commander-in-chief of the Mughal Army, Nizam-ul-mulk, was routed at Bhopal by the Maratha army. This essentially brought an end to the Mughal Empire. In 1739, Nader Shah, emperor of Iran, defeated the Mughal army at the Battle of Karnal. After this victory, Nader captured and sacked Delhi, carrying away many treasures, including the Peacock Throne. The Mughal dynasty was reduced to puppet rulers by 1757. The remnants of the Mughal dynasty were finally defeated during the Indian Rebellion of 1857, also called the 1857 War of Independence, and the remains of the empire were formally taken over by the British while the Government of India Act 1858 let the British Crown assume direct control of India in the form of the new British Raj.
Who attacked and plundered Delhi in 1737?
Maratha general Bajirao

Other features of the city's transportation infrastructure encompass more than 12,000 yellow taxicabs; various competing startup transportation network companies; and an aerial tramway that transports commuters between Roosevelt Island and Manhattan Island.
About how many yellow cabs operate in New York?
12,000