We, therefore, took the level from the water's edge below, to the weight. By this method it appeared that the SouthWeft fide was actually twenty feet lower than the NorthEaft one, the former being 143 feet, and the latter 163. It may, perhaps, be alledged that the ftretching of the cord muft occafion fome error. Suppofe it to have stretched fix inches, or even twice that length, the difference is very trifling; and although it might occafion the Falls to appear 8 or 10 inches lower than they actually were, yet it could not, in any manner, affect the comparative meafurement of the two fides. The breadth of the cataract, including all the windings and alfo the Ifland in the middle, is unquestionably upwards of a mile: it may not appear to be fo much; but it is well known that high banks always feem to be much nearer each other than they actually are. In the prefent cafe I have not formed my opinion from my eye alone, but chiefly from obfervations on the oppofite bank. The line which the Fall forms upon a horizontal plane has fome resemblance to a reaping hook.

I have never had fufficient leisure to take the level of the rapids immediately above the Falls; but I am much inclined to think that they amount to about half the height of the Falls themselves.-If the level of all the different currents, rapids and falls which are found between LakeSuperior and the mouth of the river St. Laurence could bet afcertained, I apprehend that the furface of the water in the former would be found to be at least one thousand feet higher than that of the latter..

At the diftance of fix or feven miles below the Falls, the face of the country defcends by a very confiderable and fudden declivity. This ridge runs many miles and divides the high land in the vicinity of the Falls from the low land upon which the Fort of Niagara ftands.

It is univerfally believed that the cataract was originally at this ridge, and that it has by degrees worn away and

broke

broke down the rock for the space of these fix or seven miles. Some have fuppofed that from these appearances, conjectures might be formed of the age of this part of the world. To enter upon fuch a calculation, it would previously be neceffary to afcertain how much the fall had retired in a hundred years, or any other certain periodSuppose that we were even in poffeffion of fuch a fact, ftill the conclufions drawn from it would be liable to the greatest uncertainty, as it is evident that the space of rock broke down and worn away in a certain number of years would not always be the fame.-The more or leis hardnefs and brittleness of the rock in different parts; the greater or less severity of the frofts in different years; and the quantities of water that flowed at different periods in the cataract of the river, would all occafion confiderable variations. This retroceffion of the Falls does not by any means go on fo quickly as fome have imagined. During nine years that I have remained at Niagara, very few pieces of the rock have fallen down which were large enough to make any fenfible alteration in the brink; and in the space of two years I could not perceive, by a pretty accurate measurement, that the North-Eaft brink had in the leaft receded. If we adopt the opinion of the Falls having retired fix miles, and if we fuppofe the world to be 5700 years old, this will give above fixty-fix inches and an half for a year, or fixteen yards and two thirds for nine years, which I can venture to say has not been the cafe fince 1774. But if we accede to the opinion of fome modern philofophers, and fuppofe that America has emerged much later than the other parts of the world, it will neceffarily follow that this retrograde motion of the Falls must have been quicker, which is a fuppofition ftill lefs confonant to the obfervations of late years,

Obfervations

No. VII.

Obfervations on the probabilities of the Duration of Human Life, and the progrefs of Population, in the United States of America; in a Letter from WILLIAM BARTON, ESQ. to DAVID RITTENHOUSE, L. L. D. President, A. P. S.

18, 1791.

DEAR SIR,

I B

Read Mar. BEG leave to communicate to our Philofophical fociety, the following obfervations, on the probabilities of the duration of human life, in this country;—and, likewise, on the progrefs of its population; together with the causes which accelerate that progreffion, in a degree unparalleled elsewhere. By comparing the refults, with fimilar eftimates made for fome European countries-the advantages on the fide of the United States, in these respects, will be readily difcerned.

There is not, perhaps, any political axiom better established, than this,-That a high degree of* population contributes greatly to the riches and ftrength of a state. In fact, the progreffive increase of numbers, in the people of any civilized country, is reciprocally the cause and effect of its real wealth: and, therefore, there cannot be a furer criterion by which we may judge, whether a nation be, in reality, on the rife or on the decline, than by obferving, whether the number of its inhabitants increase or diminish.

If, then, numbers of people conftitute (or, at least, contribute to) the ftrength and riches of a ftate; that country, whofe population is rapidly advancing, may fairly be faid to be increafing in both these concomitants of national profperity, with proportionable celerity. For, if a country exhibits fo unequivocal a test of strength and VOL. III.

D

riches,

"The encouragement of population ought to be one of the first objects of policy, in every State." Dr. Price.

riches, as that circumftance indicates,---a good fyftem of government, well administered, muft infure its profperity (fo far as human efforts can produce the end;) notwithstanding the tranfitory effect of fuch incidents, as have no neceffary connection with, or permanent influence upon, the fundamental fources of a nation's welfare: Thefe could only occafion a temporary derangement in the political œconomy of the ftate, whereby the operation of the national refources might, for a time, be fufpended; during which interval there might be an appearance (or even an actual exiftence, in fome degree,) of public debility and diftrefs.

If thefe obfervations be applied to the United States of America, it will appear, that this country poffeffes, in a fuperior degree, an inherent, radical and lafting fource of national vigor and greatnefs :-For, it will be found, that, in no other part of the world, (at least, in none of those parts with which we are beft acquainted) is the progrefs of population fo rapid, as in thefe ftates.-And this increase arifes from the falubrity of the climate; the great fruitfulness and refources of the country; the confequent facility of acquiring the means of a comfortable fubfiftence, which, aided by the benign influence of our government, produces* early marriages ;-and, laftly, from thef virtuous and fimple manners of the great body of our inhabitants. These are either the proximate or remote caufes which accelerate the population of this favoured land; independently of acceffions to our numbers, occafioned by migrations from foreign countries.

As

In a letter written in the year 1768, by our venerable Franklin, to John Alleyne; Efq. (in anfwer to one wherein Mr. Alleyne had requested to know the Doctor's impartial thoughts, on the fubject of an early marriage,) there is this paffage." With us in America, marriages are generally in the morning of life,---our children are therefore educated, and fettled in the world, by noon; we have an afternoon and evening of chearful leizure to ourfelves,---such as your friend at prefent enjoys. By thefe early marriages, we are bleft with more children; and, from the mode among us---founded in nature---of every mother fuckling and nurfing her own child, more of them are raised. Thence the fwift progrefs of population, among us,--unparalleled in Europe!"

"A nation fhall be more populous, in proportion as good morals and a fimplicity of taste and manners prevail; or, as the people are more frugal and virtuous."---Wallace's Differtation on the numbers of mankind, in ancient and modern times.

As a plenitude of inhabitants is of fo much importance to the interests of a nation, numerous estimates have been made, of the state and progrefs of population in divers countries; and the circumftances are defignated which occafion its growth or declenfion, in different places and at particular seasons. The refults of estimates, on this fubject, furnish useful reflections to a contemplative mind: they are not only instructive to the moralift and pleafing to the mere speculative philofopher; but they are peculiarly interefting to the statesman and the medical enquirer.

In order to fhew the difference between the progrefs of population in this country, and that in fome parts of the old world, as well as in the probabilities of the duration of life in each, respectively,—I shall offer some remarks from fuch data, as, I prefume, will be fatisfactory on the occafion. Although the kind of documents, on which calculations of this nature are ufually founded, could not, in relation to this country, be obtained in so perfect a state, as to warrant very accurate inferences from them, in every particular, the deductions, in general, are neverthelefs not far from the truth.-It is greatly to be wished, that the several religious denominations of christians, throughout the United States,—at least, in our confiderable towns and well fettled parts of the country,--would be at the pains of obtaining and publishing, every year, lifts of the births and deaths in their refpective parishes or congregations; together with the proportion of the fexes in each lift, the ages of the deceased, their diseases, and the numbers dying in each month. The number of marriages fhould alfo be added: and it would, moreover, be useful D 2

to

"La population eft un des plus fûrs moyens de juger de la profpérité d'un empire; et les variations q'elle éprouve, comparées aux évènemens qui les precèdent, font la plus jufte mesure de l'influence des caufes phyfiques et morales, fur le bonheur on fur le malheur de l'espèce humaine."---See a paper on the births, marriages and deaths, at Paris, &c. by M. de la Place, Hift. Royal read fciences, for 1783.

"La connoiffance des probabilities de la durée de la vie, eft une des chofes les plus intereffantes dans l'hiftoire naturelle de l'homme."---See M. de Buffon's effay on the probabilities of the duration of life---in the fupplement to the Nat. History,