[2] Hall's experience as an American Sanskritologist in Benares can be found in a review of his friend Sherring's The Sacred City of the Hindus (to which Hall contributed the introduction), in the July 1869 issue of The Christian Examiner:[5] Missionary Sherring devotes a large volume to a minute description of the holy city of Benares, because being the living oracle of the nation, presiding over the religious destiny of one hundred and eighty million, its future requires study.

Unhappily, he confines himself too much to the surface of things, giving us the dimensions of one temple after another in tedious iteration; the abundance of images, the superabundant filth, the manifest decay, the half-hidden traces of more ancient structures, marking them with a general uniformity.

But beneath all this parade of piety is the increase of the thirst for knowledge as never before, the multiplication of debating societies, the predilection of young men for study, and the absolute freedom of thought; above all, the spreading sect of the Brahmos, who co-operate with the telegraph and railroad, the canal and the metalled road, in throwing India open to the quickening civilization of Europe.

Few, indeed, study the Vedas now; Sanscrit is getting out of date; all classes are becoming scandalized by idolatry; Hinduism is held by a relaxing grasp; whenever the tide changes openly when the warm imagination of the Hindu is turned to Christianity, and his heart vitalized by its influence, India will lead the rest of Asia in casting her idols away, will be the servant of a new civilization and the herald of a higher humanity.In 1869 Hall was dismissed by the India Office, which accused him (by his own account) of being a drunk and a foreign spy, and expelled from the Philological Society after a series of acrimonious exchanges in the letters columns of various journals.

With another US citizen, Dr. William Chester Minor, he would become one of the most important (and most obsessive) collaborators the OED Project's director Sir James Murray (1837–1915) had, and is recognized as such in many of the prefaces to the Dictionary itself.

According to scholar Elizabeth Knowles, who studied the Murray-Hall correspondence in the OED archives, Hall spent "four hours a day...on proofs" and that "for much of the rest of the time, he was reading for vocabulary."

Murray himself would say that "Time would fail to tell of the splendid assistance rendered to the Dictionary by Dr. Fitzedward Hall, who devotes nearly his whole day to reading the proofs...and to supplementing, correcting, and increasing the quotations taken from his own exhaustless stores.

Those who know his books know the enormous wealth of quotation which he brings to bear upon every point of English literary usage; but my admiration is if possible increased when I see how he can cap and put the cope-stone on the collections of our 1500 readers."