MOR

625

MOR

'tnperfectly, and without going upon any fixed principles, orshewing particularly ilow tables of observation ought to be formed,ar >d how far in different circumstances, and at different ages, theya re to be depended on. The way of doing this, and' in generaltee right method of forming genuine tables of observation fortowns, may be learned from the following rule : “ From the sum°t all tliat die annually, after any given age, subtract the number°f annual settlers after that age; and the remainder will be thedumber of the living at the given time.” If, therefore, the num-ber of amiual,setllers in a town at every age could be ascertained,a perfect table of observations might be formed for that townfrom the bills of mortality, containing an account of the ages at"hich ali die in it. Hut no more can be learned in this instance,from any bills, than the whole number of annual settlers, and thegeneral division of life in which they enter. This, however, maybe sufficient to enable us to form tables that shall be tolerably ex-at t. For instance ; Suppose the annual deaths in a town whichhas not increased or decreased, to have been for many years in theproportion of 4 to 3 to the annual births. It will hence follow,that i of the persons who die in such a town are settlers, or emi-grants from other places, and not natives; and thesudden increase1,1 the deaths after 20-will also shew, agreeably to what was beforeobserved, that they enter after this age. In forming, therefore, atable for such a town, a quarter of all that die at all ages throughoutthe whole extent of life must be deducted from the sum of allthat die after every given age before 20 ; and the remainder willbe the true number living at that given age. And if at 20, andevery age above it, this deduction is omitted, or the number ofthe living at every such age is taken the same with the sum of allthat die after it, the result will be (supposing most of the settlers toopine in before 30, and all before 40) a table exact till 20; toohigh between 20 and 30 ; but nearly right for some years before*0 ; and after 40 exact again. Such a fable, it is evident, will bethe same with the table last described at all ages above 20, anddifferent from it only under 20. if is evident also, that on ac-count of its giving the probabilities of life too great for some yearsa fter 20, the number of inhabitants deduced from it may be de-pended on as somewhat greater than the truth ; and more or lesss °> as the annual recruits enter in general later or sooner after 29.-fret us now consider what the result nt these remarks will be, whena Pplied particularly to the London bills. It must be here lirstobserved, that at least one-quarter of all that die in London aresuppliers or settlers from the country, and not natives. The medi-um of annual burials for 10 years, from 1759 to 1768, was 22,956;°t births 15710. The excess is 7246, or near a third of the bu-Lals. The same excess during 10 years befoie 1750 was 10,500,Ur near half the burials. London was then decreasing. For thelist 12 or 15 years it has been increasing. This excess, therefore,agreeablv to the foregoing observations, was then greater than theuumber of annual settlers, and it is now less. It is however here,j Upposed, that the number of annual settlers is now no more thata quarter of the annual burials, in order to allow for more omiss "ms in the births than the burials ; and also in order to be more? 'irc of obtaining results that shall not exceed the truth. 01 everyi6i)i) then who die in London only 750 are naiives, and 250 areRemits, who couie to it after 18 or 20 years of age; and, conse-quently, to obtain from the bills a more correct table than thefirst of the following tables, 250 must be subtracted from every°Ue of the number \n the second column till 20; and the numbers111 the third column must be kept the same, the bills always givingthese right. After 20. the table is to be continued unaltered; and'he resuit will be, a (able which will give the numbers of the livingstallages in London much nearer the truth, but still somewhatto.o high. Such is the second of (he following tables. 1 he sumall the numbers in the second column oi this table, diminishedl'y 500, is 20,759. For every 1000 deaths, therefore, in London ,there are, according to this table, 20,750 living persons in it; orjor every single death 20-j inhabitants. It was before shewn, tliatthe number of inhabitants in London could not be so great, as 25tunes .3. the deaths. It now appears (since the numbers in the se-cond column of this table are too high) that the number ot inha-tutants in Loudon cannot be so great as 20 times the deaths.- , vnd tlris is a conclusion which every one, who will bestow due at-tention on what has been said, will find himself forced to receive.Vn t. ui. —no, 149.

It will not be amiss, however, to confirm it by the following fact,the knowledge of which is derived from the particular enquiry andinformation of Mr. Harris, the late ingenious master of the royalmathematical school in Cbrist-Church hospital. The average oflads in this school has, for 30 years past, been 831. They are ad-mitted at all ages between seven and 1 1 ; and few stay beyond 16 :they are therefore, in general, lads between the ages of eigiit and16. They have belter accommodations Ilian children commonlyhave; and about 300 of them have the advantage of being edu-cated in the country. Tn such circumstances, it may be wellreckoned, that the proportion of children dying annually must beless than the general proportion of children dying annually at thesame ages in London . The fact is, that for the last 30 years 12-$have died annually, or one in 70f. According to Table 11. onein 73 dies between 10 and 20, and one in 70 between eight and 16.That table, therefore, probably gives the decrements of'tife in Lon-don , at these ages, too little, and the numbers of the living toogreat: and if ibis is true of these ages, it must be true of all otherages under 20 ; and it follows demonstrably, in conformity towhat was before shewn, that more people settle in London after20 than the fourth above supposed ; and that from 20 to at least30 or 35, the numbers of the living are given too great, in pro-portion to the decrements ot life. In this table the numbers in thesecond column are doubled at 20, agreeably to what really hap-pens in London ; and the sum of the numbers in this column di-minished by half the whole number of deaths, gives the expecta-tion of life,’not of a child just born, as in other tables, but of allthe inhabitants-ol London at the time they enter it, whether that| be at birth or at 20 years of age. The expectations, therefore, andthe values of London lives under 20, cannot be calculated fromthis table. But it may be very easily fitted for this purpose, byfinding the number of births which, according to the given de-crements of life, will leave 4y4 alive at 20 ; and then adapting theintermediate numbers in such a manner to this radix, as to pre-serve all along the number of the living in the same proportion to(lie numbers of the dead. This is done in the third of the follow-ing fables, and this table may be recommended as .betteradapted to the present state of London than any other (able. Thevalues of lives, however, deduced from it, are in general nearlythe same with those deduced by Mr. Simpson from the London bills as they stood 60 years ago; (See Annuities.) The maindifference is, that after 52, and in old age, this table gives themsomewhat lower than Mr. Simpson’s table. The difference be-tween the rate of human mortality in great towns and in countryparishes and villages, may be found from various tables in Sir J.

S nclair’s Statistical Account of Scotland ; as well as from the Rev.D. Wilkie’s table and calculations for the county of Fife , insertedunder the article Annuities. But alter all, the bills of mortality inmany parts of Great Britain must be acknowledged to be materi-ally defective ; the deficiencies are ascribed chiefly to the follow-ing circumstances : 1. Many congregations of dissenters inhabit-

ing towns have their own peculiar burying grounds ; as have like-wise the Jews, and the Roman Catholics who reside in London .2. Some persons, from motives of poverty or convenience, intertheir dead without any religion; ceremony ; this is known to hap-pen in the Metropolis, in Bristol, and Newcastle-upon-Tyne , andmay happen in a lew other large towns. 3. Children who die be-fore baptism are interred without any religious ceremony, andconsequently are not registered. 4. Many - persons employed in(lie army and in naviga ion die abroad, and consequently (heirburials remain unregistered. 5. Negligence may be supposed tocause some omissions in the registers, especially j n those small be-nefices where the officiating minister is not resident. Whatevermay be the total number of deaths and burials, winch from theseseveral circumstances are not brought to account, it has been es-timated that about 5000 of (hem may be attributed to the metro-polis, and a large portion of the rest may be ascribed to the other’great (owns, and to Wales,where the registers are less carefully keptthan in England. In Scotland the registers of mortality have notyet been so generally established as in England, and those whichare kept are subject to still greater inaccuracies. The folio (vineare the tables alluded to in the foregoing dissertation upon the billsof mortality, and are allowed to be as accurate as the circum-stances under which they were constructed could possibly admit.

7 U Mortality.,