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proportion to the whole population ; and that consequently variations in either of these, which may take place from temporary causes, cannot possibly be accompanied by similar variations in the whole mass of the population. An increase in the births of one-third, which might occur in a single year, instead of increasing the population one-third, would only perhaps increase it one-eightieth or ninetieth.
It follows therefore, as I stated in the last chapter, that the table of the population for the century previous to 1780, calculated from the returns of the births alone, at the distance of ten years each, can only be considered as a very rough approximation towards the truth, in the absence of better materials, and can scarcely in any degree be depended upon for the comparative rate of increase at particular periods.
The population in 1810, compared with that of 1800, corrected as proposed in this chapter, implies a less rapid increase than the difference between the two enumerations; and it has further appeared that the assumed proportion of births to deaths as 47 to 291 is rather below than above the truth. Yet this proportion is quite extraordinary for a rich and well-peopled territory. It would add to the population of a country one 79th every year, and, were it to continue, would, according to table ii. p. 168 in this volume, double the number of inhabitants in less than fifty-five years.
This is a rate of increase, which in the nature of things cannot be permanent. It has been occasioned by the stimulus of a greatly-increased demand for labour, combined with a greatly-increased power of production, both in agriculture and manufactures. These are the two elements necessary to form an effective encouragement to a rapid increase of population. A failure of either of these must immediately weaken the stimulus; and there is but too much reason to fear the failure of one of them at present. But what has already taken place is a striking illustration of the principle of population, and a proof that in spite of great towns, manufacturing occupations, and the gradually-acquired habits of an opulent and luxuriant people, if the resources of a country will admit of a rapid increase, and if these resources are so advantageously distributed as to occasion a constantly-increasing demand for labour, the population will not fail to keep pace with them.
Of the Checks to Population in Scotland and Ireland.
An examination, in detail, of the statistical account of Scotland, would furnish numerous illustrations of the principle of population ; but I have already extended this part of the work so much, that I am fearful of tiring the patience of my readers ; and shall therefore confine my remarks in the present instance to a few circumstances which have happened to strike me.
On account of the acknowledged omissions in the registers of births, deaths and marriages in most of the parishes of Scotland, few just inferences can be drawn from them. Many give extraordinary results. In the parish of Crossmichael • in Kircudbright, the mortality appears to be only 1 in 98, and the yearly marriages 1 in 192. These proportions would imply the most • Statistical Account of Scotland, vol. i. p. 167.
unheard-of healthiness, and the most extraordinary operation of the preventive check; but there can be but little doubt that they are principally occasioned by omissions in the registry of burials, and the celebration of a part of the marriages in other parishes.
In general, however, it appears from registers which are supposed to be accurate, that in the country parishes the mortality is small ;, and that the proportions of 1 in 45, 1 in 50, and 1 in 55, are not uncommon. According to a table of the probabilities of life, calculated from the bills of mortality in the parish of Kettle by Mr. Wilkie, the expectation of an infant's life is 466“, which is very high, and the proportion which dies in the first year is only one 10th. Mr. Wilkie further adds, that from 36 parish accounts, published in the first volume, the expectation of an infant's life appears to be 40-3. But in a table which he has produced in the last volune, calculated for the whole of Scotland from Dr. Webster's survey, the expectation at • Statistical Account of Scotland, vol. ij. p. 407.