Willan, writing of fever in London in 1799, mentions that even the passages of tenement houses were “kept dark in order to lessen the window-tax,” and the air therefore kept foul[153]. Ferriar, writing of Manchester in the last years of the 18th century, mentions, among other fever-dens, a large house in an airy situation which had been built for a poor’s-house, but abandoned: having been let to poor families for a very trifling rent, many of the windows and the principal entrance were built up, and the fever then became universal in it[154]. The Carlisle typhus described by Heysham for 1781 began in a house near one of the gates, tenanted by five or six very poor families; they had “blocked up every window to lessen the burden of the window-tax[155].” John Howard’s interest having been excited in the question of gaol-fever, he noted the effects of the window-tax not only in prisons but in other houses. The magistrates of Kent appear to have paid the tax for the gaols in that county from the county funds; but in most cases the burden fell on the keepers of the gaols. “The gaolers,” says Howard, “have to pay it; this tempts them to stop the windows and stifle their prisoners;” and he appends the following note: “This is also the case in many work-houses and farm-houses, where the poor and the labourers are lodged in rooms that have no light nor fresh air; which may be a cause of our peasants not having the healthy ruddy complexions one used to see so common twenty or thirty years ago. The difference has often struck me in my various journeys[156].” Such impressions are known to be often fallacious; but in the history of the window-tax, which we shall now follow, it will appear that there was a new law, with increased stringency, in the years 1746-1748, corresponding to the “twenty or thirty years ago” of Howard’s recollection. The window-tax was originally a device of the statesmen of the Revolution “for making good the deficiency of the clipped money.” By the Act of 7 and 8 William and Mary, cap. 18, taking effect from the 25th March, 1696, every inhabited house owed duty of two shillings per annum, and, over and above such duty on all inhabited houses, every dwelling-house with ten windows owed four shillings per annum, and every house with twenty windows eight shillings. In 1710 houses with from twenty to thirty windows were made to pay ten shillings, and those with more than thirty windows twenty shillings. Various devices were resorted to to check the evasions of bachelors, widows and others. A farmer had to pay for his servants, recouping himself from their wages. A house subdivided into tenements was to count as one; which would have made the tax difficult to gather except from the landlord. The machinery of collection was a board of commissioners, receivers-general and collectors.