There is something connected with the census of Dublin published in Thom's directory from official documents which may be more interesting to some than any description of the Irish capital, however graphic. This something is an evident error that has, by some means, been made in enumeration of its inhabitants. According to the published census, there were in round numbers 13,000 more people in Dublin in 1851 than in 1891; and only 14,000 more in county and city included in 1891 than in 1851. There is a gross error here, for between the two epochs mentioned, the increase in what is generally known as the metropolitan district has been so great that it is visible to anyone who has been familiar with Dublin for forty years. It is known that since 1851 nearly 25,000 houses have been erected in city and county. That number of houses would represent at least 100,000 people, but it only represents 14,000 according to the census, or two-thirds of a person to each house! It may be said that a great many houses have been pulled down in the city since 1851. True, there have; but ten have been built since then for the one that has been pulled down. There are at least a dozen streets, large and small, in Dublin, the population of which is four times greater than it was in 1851; for there were no tenement houses in those streets then, whereas they are all tenement houses now, and consequently there are four or five families instead of one in each house. The great increase in the population of Dublin during the last forty or forty-five years is quite apparent in the more crowded state of the thoroughfares. It seems not only probable, but certain, from all the data that can be got at outside the census, that there are from fifty to one hundred thousand more people in what is known as the metropolitan district of Dublin than is shown by the published census. This will go far to account for the weekly death-rate of Dublin being generally higher than that of any other city in these islands; for if the weekly number of deaths is based on a population less than what it is, it will make the weekly death-rate per thousand higher than it should be. This is a very serious matter for Dublin, for nothing has a more detrimental effect on the welfare of a city than getting the name of being unhealthy.