398 EARTH. 
cumulated new foil ; and the two others, which, in 1421, 
and 1446, formed alfo many gulfs, in the fouth part of 
the fame land, on the prolonged courfe of the Waal and 
the Meufe: to which irruptions, fome more recent, that 
happened from the fame caufe in fome parts of the Baltic , 
efpecially in the peninfula of Jutland , have been added 
by this fame elms of geologills. Thefe are, indeed, 
dreadful events in the hi(lory of mankind: for thoufands 
of inhabitants perifhed by the entire fubmerlion of their 
dwellings, which even funk into the ground, that was 
then reduced again to mud: but in refpec’t of the conti¬ 
nent itfelf, it loft only a part of the new lands, which, 
having been -too early inclofed, had already funk below 
the loweft level of the fea. It is eafy to conceive, that a 
high and agitated fea, breaking the dikes of fuch lands, fell 
over them with an impetuolity capable of reducing their 
loofe foil into mud, and to wafh it away. A great part 
of the beautiful country of Holland , the remains of the 
new land above deferibed, would be expofed to the very 
fame accident, if, from the opulence and greater know¬ 
ledge of the inhabitants, there were not a ftridt watch 
kept, and great expence beftowed on every part of its 
dikes, for maintaining them in conftant repair: for, if the 
Zuyder-fep, or the main river, were to break open thofe 
dikes, that country would be loft paft recovery, up to the 
continental land-, which was the cafe in the above irrup¬ 
tions; and there would remain only a firing of fand-iflands 
bordered with dunes, as thofe are which range before the 
entrance of the Zuyder-J'ee, and extend, at a certain dif- 
tance, round Zealand. 
We know then the real caufe of thofe dreadful and ir¬ 
reparable fubmerfions of fome new lands: thofe which 
have undergone that fate, had been inclofed at too fmalla 
diflance of time from their formation, or from the origin of 
our continents, when the fediments of the fea and of the 
riws began to gather in thofe places. New lands, fo 
formed, require a certain length of time to fettle and be¬ 
come firm. While yet uninclofed, though raifed above 
the common level of the fea, they fink alfo for a long 
time ; but as long as they are lowered by that caufe, 
they continue to be overflowed by the fea and the rivers 
every time they rife above a certain level; whereby the 
low lands receive new fediments on their furface, till at laft 
they become firm. But if a new land is inclofed, only 
becaule it is but feldom overflowed, and without confi- 
dering its age, finking then, without receiving new fup- 
plies of fediments on its top, it may be deprefled below 
the loweft level of the fea: which was the cafe of the 
new land between the Waal and the iff el. But fome new 
lands have not been fo early inclofed, and we have an ob¬ 
ject of companion in that refpeCl, from a new land next 
to that firft, between the IJfel and the Eetns, which will lead 
us to an eftimate of the length of time that may prevent fuch 
finking. The new land which we have now in view, is a 
'peninfula that contains the low grounds belonging to the 
provinces Friefand and Groninguen. When the inhabi¬ 
tants of that country undertook to improve their new 
lands, they did not inclofe them: their l'ettlements were 
on the edge of the continent.d land, where are now the 
towns of Groninguen, in the province of that name, and 
of Leeuwarden in that of Friejland-, whence they began to 
cultivate the low land, though Hill expofed to inunda¬ 
tions. By cutting ditches and channels, they obtained 
materials for raifing the ground in fome places, where 
they built their farm-houfes and fome villages, which 
thus were fecured again!! the floods. I have feen thofe 
materials; tlfey are a clayey fea-fand, mixed with recent 
fhells. At that lime the inhabitants could cultivate no 
grains but what were fown in the fpring, and fometimes 
they even loft their crops; but in the mean time the land 
was improved, and it rofe yearly ; for the waver, by riling 
and_retiring flowly, alv/ays left new fediments, which were 
very fertile, and at rhe fame time compcnlated the finking 
of the mafs: and when thofe lands became firm, they in- 
creafed fenfibly in height. This has been the practice 
on many other parts of thofe coafis, where the inhabitant? 
were not rich enough to be bad economifts. 
In the fixteenth century, a great traft of new lands in 
both the above provinces was only expofed to temporary 
inundations in winter : andGASPARD Roblez, a Spanifh 
governor, undertook to inclofe it with dikes. That work 
was completed in 1570; but as the outward new lands, 
though (till expofed to frequent inundations, were of a 
fnfficient age for being firm, a century more brought an 
almoft equal tract of thofe lands to the fame ftate as the 
firft, which then was alfo inclofed. The progrjs of that 
increafe has not yet been checked, becaufe of the range of 
new ifiands formed in the fea at fome diftance, which pre¬ 
vents too great an accefs of fea-fand ; by which means the 
fediments of the rivers are fnfficient for binding the fand 
on the fore-part of the new lands. Every generation, by 
private undertakings of the inhabitants next to the fea, 
inclofes fome new parts of thofe exte.nfions, and no Jinking 
is obferved within the dikes. The inclolers always leave 
out of their dikes the parts of the new grounds which are 
ftill expofed to frequent inundations: they afford pafture 
for their cattle during a great part of the year; and every 
time that they are overflowed, they improve for future 
generations. Now, had we only that well-known progrefs 
of an operation, which mufi have degun at the origin of our 
continents, nothing could contradict that proof that they 
are not very old: and when we compare alfo the fteadinefs 
of that peninfula, inclofed only in 1570, with the finking 
of the next, the remains of which is Holland, there can 
be no doubt, that the Btlgi inclofed the laft at too fmall a, 
diflance from its origin. 
I fliall now refume that particular demonftration under 
a general view. Wherever there is an increafe of land by 
the influence of the Jea and rivers, it is very eafy to dif-. 
tinguifli the original boundaries of the continent, from which 
the new land may be meafured ; and if there is any monu¬ 
ment or record, that determines fome fiage in its progrefs, 
the ratio between the increafe from that point, and what had 
been produced before, is a real chronometer. I have made 
that fort of obfervation on many parts of our coafis, and 
I have always found the fame general refult. All thofe 
patched works have begun at the fame time; and their 
differences, in extent and rapidity of progrefs, proceed 
from a combination of the depth of the fea near the coafis 
with the nature of its bottom, the fituation of the coafi, 
and the quantity of fediments of the rivers. The outward 
afpeft of thofe new lands is l'ufficient for difeerning them, 
but their compolition ferves alfo to diftinguilh them in 
depth, by boring through them. This has been the cafe 
by the want o if reft water for their inhabitants: they fink 
wells through the patched land, and, when they attain the 
original foil, they often find in it fprings which filtrate in 
t he prolonged firata of the next continental ground. 
So far, fir, I have only followed your own directions: 
I have examined various pragreJJ'es going on by natural 
caufis, namely, the actions of gravity and of water, from 
the tops of the mountains, to the fia-fhore \ and in that lur- 
vey I have Ihewn you various modiila for the calculation 
of the time elapfed Juice the origin of our continents. But thefe 
procejfes are only fome particular claffes in the variety of 
different ejfcEls which were to begin at the fame time, from 
known natural caufis, when fuch a revolution took place 
as formed a dry land from what was before the bottom cf 
the fea. At that time, every eifect obferved on our conti¬ 
nents, except their general lhape, and the nature of their 
materials, began to take place, and has continued ever 
lince: confequently, if, by following the fame princi¬ 
ples of invelligation, applied to different procejfes depend¬ 
ing on diftinCt caufes, we find, in refpeCl of the time when 
they began, the lame general refult as from the former ; 
that agreement will produce a degree of certainty in our 
invelligation, much beyond what would have appeared 
to you latisfaCtory, from only one clafs of unequivocal 
phenomena. 
Since our mountains, which have been under the fea, arc 
now 
