The number in the former period is as 1.7 to 9.3; whereas that in the latter is only as 1.5 to 11.5, of the whole number of registered funerals.

But injurious as large towns may be to the duration of life, and though it must be granted that by annually draining the country of a number of inhabitants, they confume many lives, which, in their original fituation, might have continued to exist for several years longer, but are cut off by diseases produced by vitiated air, by infection, or by a change in their modes of living, yet on the whole, they are not, perhaps, fo unfavourable to population as they may, at firft fight, appear. For in large towns, at leaft in those where extenfive manufactures are carried on, the encouragements to matrimony are confiderable; and, therefore, if life be more speedily wafted, it is, probably, produced in a far greater ratio*. A fenfible, industrious manufacturer confiders his children as his treasure, and boasts that his quiver is full of them; for where children can be employed at an early age, the fear of a large family is not only diminished, but

That this is actually the cafe in Manchester and Salford appears from the registers, although during a period of twenty-one years the marriages and births have been more than doubled, yet the increase of burials is only as 29 to 16.

every child that is born may be regarded as an addition of fortune.

A large and populous town, alfo, is favourable to population, by extending its influence, to a very confiderable distance, beyond its own diftricts. Manchester fupplies employment to many thousand people, refident within the country, to the extent of feveral miles, who gain a comfortable livelihood, in different branches of the manufactory, without fuffering the inconveniences which attend the town. The demand of this great body of people, who raise but a very small part of the provifions they confume, added to that of the town, has an effect upon a ftill larger tract of country, the inhabitants of which are occupied in agriculture; and, being fure of finding a ready and advantageous mart for their products, they are encouraged to a better tillage of their lands, already in cultivation, and to the improvement of wafte lands; and that cultivation and competency will increafe population by removing the obftacles to matrimony, is an axiom, the truth of which. cannot be disputed.

That the increase of the adjacent country keeps pace with that of the town, appears from the state of population in the neighbouring pa-* rish of Eccles, where the bills of mortality are kept with an exemplary degree of accuracy. The clerk, at the fame time that he distributes,

through

through the parish, the bill for the preceding year, makes an actual enumeration of the families, houses, and individuals. In the year 1776 the number of inhabitants was 7936, and, in the year 1785, 10522, fo that in nine years there has been an addition of 2586 people. And, if we may truft the obfervation of our fenfes the increase has been, at least, equal, in most of the parishes to which the manufactory extends.

I find an article in the bill of mortality, for the parish of Eccles, in the year 1784, afcertaining the number of ex-parishioners, buried there, in that year, which amounts to ninetyfive. From the fituation of the church, as diftant from every other parish but that of Mancheiter, I am convinced that, by far the greatest proportion of them come from hence. And as I have alfo no doubt, but there are greater numbers carried out to the different chapels of ease and neighbouring parishes than are brought in from other townships and parishes, I believe I may ventureto affert that, the number of deaths, in Manchester and Salford, are greater than they appear to be from our own parish regifter. The burial grounds within the towns, are either fo crowded, or fo expenfive, as to deter many perfons from depofiting their deceased relations in them. Yet, even making every allowance of this kind, the great fuperiority of the births over the burials cannot be difputed. During the laft

fix years, though the latter have been unusually numerous, the registered births have exceeded the registered burials, by an average of 433, annually*.

• Since this paper was read, the bills of mortality, for the years 1786 and 1787, have been published. In the former year, the registered births amounted to 2219, and the burials to 1282; fuperiority of births 937. In the latter, the births were 2256, and the burials 1761-fuperiority, 495. And as none of the diffenters are baptized, though many are buried, at the churches, the proportions of births to burials is ftill greater than is ftated. Taking the year 1785 into the account fo as to form a period of three years; the average annual number of births, during that period, will be 2139, and that of the deaths, 1592. The former multiplied by 26.5 produces 56683, and the latter, by 30.5 produces 48556; the average of thefe numbers will be 52619, and if we allow fifty unregistered funerals and 150 births for the diffenters, and multiply and average these as above, we shall have 2745, which added to 52619, will produce 55364, and may be received as nearly the number of inhabitants in Manchester and Salford at the beginning of the present year.

AUGUST 25, 1788.

CONJECTURES

CONJECTURES relative to the CAUSE of the INCREASE of WEIGHT acquired by fome HEATED BODIES, during cooling; by THOMAS HENRY, junior. Communicated by THOMAS HENRY, F. R. S. &c.

M

READ MARCH 28, 1786.

ANY experiments have been made by different perfons, with a view to determine, whether the addition of actual heat to bodies does increase their weight. M. Buffon has afferted, that a ball of iron, weighing, when cold, 49lb. 11 oz. increafed in weight, when made of a white heat, in the proportion of 19 grains to every pound. But, it is very probable, that, in this experiment, there was fome fallacy, fince we find it directly contradictory to the refults both of the experiments made by Dr. Roebuck*, and of thofe made by Mr. Whitehurst. The first of thefe two Gentlemen found, that a cylinder of wrought iron, heated to a welding heat, at which time it weighed, in a very accurate balance, fifty-five pounds,

* Phil. Tranf. vol. LXVI.

† lb.

gradually