London, the capital of England and metropolis of the British empire, is situated on the banks of the Thames, in the counties of Middlesex and Surrey, and within a day's journey of the southern shore of Britain. On the spot now occupied by the city, or more ancient part of the metropolis, which is on the left or northern bank of the Thames, a town had been built and possessed by the Romans eighteen centuries ago, and from that period it has constantly been the seat of the increasing and busy population. Its chief increase and improvement, however, have been since the great fire in 1666, which destroyed a large number of the old streets and public edifices. It is impossible by any written description to convey adequate ideas of the real magnitude of London. Indeed,[261] it is not until after a person has been in the city for some months, that he begins to comprehend it. Every new walk opens to him streets, squares and divisions which he has never seen before. And even those places where he is most familiar, are discovered day by day to possess archways and thoroughfares within and around them, which had never been noticed before. Even people who have spent their whole lives in the city, often find streets and buildings, of which they had never before heard, and which they had never before seen. The Thames Tunnel which is the medium for communication between the Surrey and Middlesex sides of the river, was designed and carried into execution by a joint stock company, which, however, has been largely assisted by government. The tunnel consists of two avenues or arched vaults, beneath the river. Each avenue is of such height and breadth as to afford a beautiful walk, and is lighted with gas. It is about two miles below London bridge, and was begun in 1822. Standing in some measure behind the site of the Royal Exchange, facing Threadneedle street, are seen the extensive series of stone buildings containing the Bank of England. The whole buildings and courts include an area of about eight acres, and were completed in 1778. In 1832, there were employed in the bank 820 clerks and porters, and 38 printers and engravers. There were besides, 193 pensioners. The salaries and pensions amounted to £218,003; the house expenses, £39,187, and the allowance to directors, £8,000. These statistics will give the reader a better opportunity[262] to judge of the enormous amount of business that this bank transacts annually. The hours at which the bank is open are from nine in the morning till five in the afternoon, holidays excepted.