Chapter XVI: Part 16

4. _By the Frontal Moraine of an Ancient Glacier._--The barrier in
this case consists of the last moraine left by the retreating glacier.
Such lakes are abundant in the northern hemisphere, especially in
Scotland and the Alps.

5. _By Irregular Deposition of Glacial Drift._--After the retreat of
continental glaciers great masses of glacial drift are left on the
land-surfaces, but, on account of the manner in which these masses
were deposited, they abound in depressions that become filled with
water. Often these lakes are without visible outlets, the water
frequently percolating through the glacial drift. These lakes are so
numerous in the north-eastern part of North America that one can trace
the southern boundary of the great ice-sheet by following the southern
limit of the lake-strewn region, where lakes may be counted by tens of
thousands, varying from the size of a tarn to that of the great
Laurentian lakes above mentioned.

6. _By Sand drifted into Dunes._--It is a well-known fact that sand
may travel across a country for several miles in the direction of the
prevailing winds. When these sand-dunes obstruct a valley a lake may
be formed. A good example of such a lake is found in Moses Lake in the
state of Washington; but the sand-dunes may also fill up or submerge
river-valleys and lakes, for instance, in the Sahara, where the Shotts
are like vast lakes in the early morning, and in the afternoon, when
much evaporation has taken place, like vast plains of white salt.

7. _By Alluvial Matter deposited by Lateral Streams._--If the current
of a main river be not powerful enough to sweep away detrital matter
brought down by a lateral stream, a dam is formed causing a lake.
These lakes are frequently met with in the narrow valleys of the
Highlands of Scotland.

8. _By Flows of Lava._--Lakes of this kind are met with in volcanic
regions.

C. ORGANIC BASINS.--In the vast tundras that skirt the Arctic Ocean in
both the old and the new world, a great number of frozen ponds and
lakes are met with, surrounded by banks of vegetation. Snow-banks are
generally accumulated every season at the same spots. During summer
the growth of the tundra vegetation is very rapid, and the snow-drifts
that last longest are surrounded by luxuriant vegetation. When such
accumulations of snow finally melt, the vegetation on the place they
occupied is much less than along their borders. Year after year such
places become more and more depressed, comparatively to the general
surface, where vegetable growth is more abundant, and thus give origin
to lakes.

It is well known that in coral-reef regions small bays are cut off
from the ocean by the growth of corals, and thus ultimately
fresh-water basins are formed.

_Life History of Lakes._--From the time of its formation a lake is destined to disappear. The historical period has not been long enough to enable man to have watched the birth, life and death of any single lake of considerable size, still by studying the various stages of development a fairly good idea of the course they run can be obtained.

In humid regions two processes tend to the extinction of a lake, viz. the deposition of detrital matter in the lake, and the lowering of the lake by the cutting action of the outlet stream on the barrier. These outgoing streams, however, being very pure and clear, all detrital matter having been deposited in the lake, have less eroding power than inflowing streams. One of the best examples of the action of the filling-up process is presented by Lochs Doine, Voil and Lubnaig in the Callander district of Scotland. In post-glacial times these three lochs formed, without doubt, one continuous sheet of water, which subsequently became divided into three different basins by the deposition of sediment. Loch Doine has been separated from Loch Voil by alluvial cones laid down by two opposite streams. At the head of Loch Doine there is an alluvial flat that stretches for 1½ m., formed by the Lochlarig river and its tributaries. The long stretch of alluvium that separates Loch Voil from Loch Lubnaig has been laid down by Calair Burn in Glen Buckie, by the Kirkton Burn at Balquhidder, and by various streams on both sides of Strathyre. Loch Lubnaig once extended to a point ¾ m. beyond its present outlet, the level of the loch being lowered about 20 ft. by the denuding action of the river Leny on its rocky barrier.

In arid regions, where the rainfall is often less than 10 ins. in the year, the action of winds in the transport of sand and dust is more in evidence than that of rivers, and the effects of evaporation greater than of precipitation. Salt and bitter lakes prevail in these regions. Many salt lakes, such as the Dead Sea and the Great Salt Lake, are descended from fresh-water ancestors, while others, like the Caspian and Aral Seas, are isolated portions of the ocean. Lakes of the first group have usually become salt through a decrease in the rainfall of the region in which they occur. The water begins to get salt when the evaporation from the lake exceeds the inflow. The inflowing waters bring in a small amount of saline and alkaline matter, which becomes more and more concentrated as the evaporation increases. In lakes of the second group the waters were salt at the outset. If inflow exceeds evaporation they become fresher, and may ultimately become quite fresh. If the evaporation exceeds the inflow they diminish in size, and their waters become more and more salt and bitter. The first lake which occupied the basin of the Great Salt Lake of Utah appears to have been fresh, then with a change of climate to have become a salt lake. Another change of climate taking place, the level of the lake rose until it overflowed, the outlet being by the Snake river; the lake then became fresh. This expanded lake has been called Lake Bonneville, which covered an area of about 17,000 sq. m. Another change of climate in the direction of aridity reduced the level of the lake below the level of the outlet, the waters became gradually salt, and the former great fresh-water lake has been reduced gradually to the relatively small Great Salt Lake of the present day. The sites of extinct salt lakes yield salt in commercial quantities.

_The Water of Lakes._--(a) _Composition._--It is interesting to
compare the quantity of solid matter in, and the chemical composition
of, the water of fresh and salt lakes:--

Total Solids by Evaporation
expressed in Grams per Litre.
Great Salt Lake (Russell) 238.12
Lake of Geneva (Delebecque) 0.1775

The following analysis of a sample of the water of the Great Salt Lake
(Utah, U.S.A.) is given by I. C. Russell:--

Grams per Litre. Probable Combination.

Na 75.825 NaCl 192.860
K 3.925 K2SO4 8.756
Li 0.021 Li2SO4 0.166
Mg 4.844 MgCl2 15.044
Ca 2.424 MgSO4 5.216
Cl 128.278 CaSO4 8.240
SO3 12.522 Fe2O3 + Al2O3 0.004
O in sulphate 2.494 SiO2 0.018
Fe2O3 + Al2O3 0.004 Surplus SO_3 0.051
SiO2 0.018
Bo2O3 trace
Br3 faint trace

The following analyses of the waters of other salt lakes are given by
Mr J. Y. Buchanan (Art. "Lake," _Ency. Brit._, 9th Ed.), an analysis
of sea-water from the Suez Canal being added for comparison:--

+-----------------------+---------+--------+-------------------+----------+---------+---------+-----------+
| | | | Caspian Sea. | | | |Suez Canal,|
| |Koko-nor.|Aral Sea+--------+----------+Urmia Sea.|Dead Sea.|Lake Van.| Ismailia. |
| | | | Open. |Karabugas.| | | | |
+-----------------------+---------+--------+--------+----------+----------+---------+---------+-----------+
| Specific Gravity | 1.00907 | .. | 1.01106| 1.26217 | 1.17500 | .. | 1.01800| 1.03898 |
| Percentage of Salt | 1.11 | 1.09 | 1.30 | 28.5 |22.28 | 22.13 | 1.73 | 5.1 |
+-----------------------+---------+--------+--------+----------+----------+---------+---------+-----------+
| Name of Salt. | Grams of Salt per 1000 Grams of Water. |
+-----------------------+---------+--------+--------+----------+----------+---------+---------+-----------+
| Bicarbonate of Lime | 0.6804 | 0.2185 | 0.1123 | .. | .. | .. | .. | 0.0072 |
| " Iron | 0.0053 | .. | 0.0014 | .. | .. | .. | .. | 0.0069 |
| " Magnesia | 0.6598 | .. | .. | .. | .. | .. | 0.4031 | .. |
| Carbonate of Soda | .. | .. | .. | .. | .. | .. | 5.3976 | .. |
| Phosphate of Lime | 0.0028 | .. | 0.0021 | .. | .. | .. | 5.3976 | 0.0029 |
| Sulphate of Lime | .. | 1.3499 | 0.9004 | .. | 0.7570 | 0.8600 | .. | 1.8593 |
| " Magnesia | 0.9324 | 2.9799 | 3.0855 | 61.9350 | 13.5460 | .. | 0.2592 | 3.2231 |
| " Soda | 1.7241 | .. | .. | .. | .. | .. | 2.5673 | .. |
| " Potash | .. | .. | .. | .. | .. | .. | 0.5363 | .. |
| Chloride of Sodium | 6.9008 | 6.2356 | 8.1163 | 83.2840 |192.4100 | 76.5000 | 8.0500 | 40.4336 |
| " Potassium | 0.2209 | 0.1145 | 0.1339 | 9.9560 | .. | 23.3000 | .. | 0.6231 |
| " Rubidium | 0.0055 | .. | 0.0034 | 0.2510 | .. | .. | .. | 0.0265 |
| " Magnesium | .. | 0.0003 | 0.6115 |129.3770 | 15.4610 | 95.6000 | .. | 4.7632 |
| " Calcium | .. | .. | .. | .. | 0.5990 | 22.4500 | .. | .. |
| Bromide of Magnesium | 0.0045 | .. | 0.0081 | 0.1930 | .. | 2.3100 | .. | 0.0779 |
| Silica | 0.0098 | .. | 0.0024 | .. | .. | 0.2400 | 0.0761 | 0.0027 |
+-----------------------+---------+--------+--------+----------+----------+---------+---------+-----------+
| Total Solid Matter |11.1463 |10.8987 |12.9773 |284.9960 |222.2600 |221.2600 | 17.2899 | 51.0264 |
+-----------------------+---------+--------+--------+----------+----------+---------+---------+-----------+

This table embraces examples of several types of salt lakes. In the
Koko-nor, Aral and open Caspian Seas we have examples of the
moderately salt, non-saturated waters. In the Karabugas, a branch gulf
of the Caspian, Urmia and the Dead Seas we have examples of saturated
waters containing principally chlorides. Lake Van is an example of the
alkaline seas which also occur in Egypt, Hungary and other countries.
Their peculiarity consists in the quantity of carbonate of soda
dissolved in their waters, which is collected by the inhabitants for
domestic and commercial purposes.

The following analyses by Dr Bourcart give an idea of the chemical
composition of the water of fresh-water lakes in grams per litre:--

+---------------+--------+--------+---------+-----------+
| | Tanay. | Bleu. |Märjelen.|St Gothard.|
+---------------+--------+--------+---------+-----------+
| SiO2 | 0.003 | 0.0042 | 0.0014 | 0.0008 |
| Fe2O3 + Al2O3 | 0.0012 | 0.0006 | 0.0008 | trace |
| NaCl | 0.0017 | .. | .. | .. |
| Na2SO4 | 0.0011 | 0.0038 | 0.0031 | 0.00085 |
| Na2CO3 | .. | .. | .. | 0.00128 |
| K2SO4 | 0.0021 | 0.0028 | 0.0044 | .. |
| K2CO3 | .. | .. | 0.0003 | 0.00130 |
| MgSO4 | 0.006 | 0.0305 | .. | .. |
| MgCO3 | 0.0046 | 0.0158 | 0.0008 | 0.00015 |
| CaSO4 | .. | .. | .. | .. |
| CaCO3 | 0.107 | 0.1189 | 0.0061 | 0.00178 |
| MnO | 0.001 | .. | .. | .. |
+---------------+--------+--------+---------+-----------+

(b) _Movements and Temperature of Lake-Waters._--(1) In addition to
the rise and fall of the surface-level of lakes due to rainfall and
evaporation, there is a transference of water due to the action of
wind which results in raising the level at the end to which the wind
is blowing. In addition to the well-known progressive waves there are
also stationary waves or "seiches" which are less apparent. A seiche
is a standing oscillation of a lake, usually in the direction of the
longest diameter, but occasionally transverse. In a motion of this
kind every particle of the water of the lake oscillates synchronously
with every other, the periods and phases being the same for all, and
the orbits similar but of different dimensions and not similarly
situated. Seiches were first discovered in 1730 by Fatio de Duillier,
a well-known Swiss engineer, and were first systematically studied by
Professor Forel in the Lake of Geneva. Large numbers of observations
have been made by various observers in lakes in many parts of the
world. Henry observed a fifteen-hour seiche in Lake Erie, which is 396
kilometres in length, and Endros recorded a seiche of fourteen seconds
in a small pond only 111 metres in length. Although these waves cause
periodical rising and falling of the water-level, they are generally
inconspicuous, and can only be recorded by a registering apparatus, a
limnograph. Standard work has been done in the study of seiches by the
Lake Survey of Scotland under the immediate direction of Professor
Chrystal, who has given much attention to the hydrodynamical theories
of the phenomenon. Seiches are probably due to several factors acting
together or separately, such as sudden variations of atmospheric
pressure, changes in the strength or direction of the wind.
Explanations such as lunar attraction and earthquakes have been shown
to be untenable as a general cause of seiches.

2. _The water temperature of lakes_ may change with the season from
place to place and from layer to layer; these changes are brought
about by insolation, by terrestrial radiation, by contract with the
atmosphere, by rain, by the inflow of rivers and other factors, but
the most important of all these are insolation and terrestrial
radiation. Fresh water has its greatest density at a temperature of
39.2° F., so that water both above and below this temperature floats
to the surface, and this physical fact largely determines the water
stratification in a lake. In salt lakes the maximum density point is
much lower, and does not come into play. In the tropical type of
fresh-water lake the temperature is always higher than 39° F., and the
temperature decreases as the depth increases. In the polar type the
temperature is always lower than 39° F., and the temperature increases
from the surface downwards. In the temperate type the distribution of
temperature in winter resembles the polar type, and in summer the
tropical type. In Loch Ness and other deep Scottish lochs the
temperature in March and April is 41° to 42° F., and is then nearly
uniform from top to bottom. As the sun comes north, and the mean air
temperature begins to be higher than the surface temperature, the
surface waters gain heat, and this heating goes on till the month of
August. About this time the mean air temperature falls below the
surface temperature, and the loch begins to part with its heat by
radiation and conduction. The temperature of the deeper layers beyond
300 ft. is only slightly affected throughout the whole year. In the
autumn the waters of the loch are divided into two compartments, the
upper having a temperature from 49° to 55° F., the deeper a
temperature from 41° to 45°. Between these lies the
discontinuity-layer (_Sprungschicht_ of the Germans), where there is a
rapid fall of temperature within a very short distance. In August this
discontinuity-layer is well marked, and lies at a depth of about 150
ft.; as the season advances this layer gradually sinks deeper, and the
layer of uniform temperature above it increases in depth, and slowly
loses heat, until finally the whole loch assumes a nearly uniform
temperature. Many years ago Sir John Murray showed by means of
temperature observations the manner in which large bodies of water
were transferred from the windward to the leeward end of a loch, and
subsequent observations seem to show that, before the
discontinuity-layer makes its appearance, the currents produced by
winds are distributed through the whole mass of the loch. When,
however, this layer appears, the loch is divided into two
current-systems, as shown in the following diagram:--

AB, Discontinuity layer.
C, Surface current.
D, Primary return current.
E, Secondary surface current.
F, Secondary return current.]

Another effect of the separation of the loch into two compartments by
the surface of discontinuity is to render possible the
temperature-seiche. The surface-current produced by the wind transfers
a large quantity of warm water to the lee end of the loch, with the
result that the surface of discontinuity is deeper at the lee than at
the windward end. When the wind ceases, a temperature-seiche is
started, just as an ordinary seiche is started in a basin of water
which has been tilted. This temperature-seiche has been studied
experimentally and rendered visible by superimposing a layer of
paraffin on a layer of water.

Wedderburn estimates the quantity of heat that enters Loch Ness and is
given out again during the year to be approximately sufficient to
raise about 30,000 million gallons of water from freezing-point to
boiling-point. Lakes thus modify the climate of the region in which
they occur, both by increasing its humidity and by decreasing its
range of temperature. They cool and moisten the atmosphere by
evaporation during summer, and when they freeze in winter a vast
amount of latent heat is liberated, and moderates the fall of
temperature.

Lakes act as reservoirs for water, and so tend to restrain floods, and
to promote regularity of flow. They become sources of mechanical
power, and as their waters are purified by allowing the sediment which
enters them to settle, they become valuable sources of water-supply
for towns and cities. In temperate regions small and shallow lakes are
likely to freeze all over in winter, but deep lakes in similar regions
do not generally freeze, owing to the fact that the low temperature of
the air does not continue long enough to cool down the entire body of
water to the maximum density point. Deep lakes are thus the best
sources of water-supply for cities, for in summer they supply
relatively cool water and in winter relatively warm water. Besides,
the number of organisms in deep lakes is less than in small shallow
lakes, in which there is a much higher temperature in summer, and
consequently much greater organic growth. The deposits, which are
formed along the shores and on the floors of lakes, depend on the
geological structure and nature of the adjacent shores.

_Biology._--Compared with the waters of the ocean those of lakes may safely be said to contain relatively few animals and plants. Whole groups of organisms--the Echinoderms, for instance--are unrepresented. In the oceans there is a much greater uniformity in the physical and chemical conditions than obtains in lakes. In lakes the temperature varies widely. To underground lakes light does not penetrate, and in these some of the organisms may be blind, for example, the blind crayfish (_Cambarus pellucidus_) and the blind fish (_Amblyopsis spelaeus_) of the Kentucky caves. The majority of lakes are fresh, while some are so salt that no organisms have been found in them. The peaty matter in other lakes is so abundant that light does not penetrate to any great depth, and the humic acids in solution prevent the development of some species. Indeed, every lake has an individuality of its own, depending upon climate, size, nature of the bottom, chemical composition and connexion with other lakes. While the ocean contains many families and genera not represented in lakes, almost every genus in lakes is represented in the ocean.

The vertebrates, insects and flowering plants inhabiting lakes vary
much according to latitude, and are comparatively well known to
zoologists and botanists. The micro-fauna and flora have only recently
been studied in detail, and we cannot yet be said to know much about
tropical lakes in this respect. Mr James Murray, who has studied the
Scottish lakes, records in over 400 Scottish lochs 724 species (the
fauna including 447 species, all invertebrates, and the flora
comprising 277 species) belonging to the following groups; the list
must not be regarded as in any way complete:--

_Fauna._ _Flora._

Mollusca 7 species Phanerogamia 65 species
Hydrachnida 17 " Equisetaceae 1 "
Tardigrada 30 " Selaginellaceae 1 "
Insecta 7 " Characeae 6 "
Crustacea 78 " Musci 18 "
Bryozoa 7 " Hepaticae 2 "
Worms 25 " Florideae 2 "
Rotifera 181 " Chlorophyceae 142 "
Gastrotricha 2 " Bacillariaceae 26 "
Coelenterata 1 " Myxophyceae 10 "
Porifera 1 " Peridiniaceae 4 "
Protozoa 91 "
----------- -----------
447 " 277 "

These organisms are found along the shores, in the deep waters, and in
the surface waters of the lakes.

The _littoral region_ is the most populous part of lakes; the
existence of a rooted vegetation is only possible there, and this in
turn supports a rich littoral fauna. The greater heat of the water
along the margins also favours growth. The great majority of the
species in Scottish lochs are met with in this region. Insect larvae
of many kinds are found under stones or among weeds. Most of the
Cladocera, and the Copepoda of the genus _Cyclops_, and the
Harpacticidae are only found in this region. Water-mites, nearly all
the Rotifers, Gastrotricha, Tardigrada and Molluscs are found here,
and Rhizopods are abundant. A large number of the littoral species in
Loch Ness extends down to a depth of about 300 ft.

_The abyssal region_, in Scottish lochs, lies, as a rule, deeper than
300 ft., and in this deep region a well-marked association of animals
appears in the muds on the bottom, but none of them are peculiar to
it: they all extend into the littoral zone, from which they were
originally derived. In Loch Ness the following sparse population was
recorded:--

1 Mollusc: _Pisidium pusillum_ (Gmel).
3 Crustacea: _Cyclops viridis_, Jurine.
_Candona candida_ (Müll).
_Cypria ophthalmica_, Jurine.
3 Worms: _Stylodrilus gabreteae_, Vejd.
Oligochaete, not determined.
_Automolos morgiensis_ (Du Plessis).
1 Insect: _Chironomus_ (larva).
Infusoria: Several, ectoparasites on _Pisidium_ and _Cyclops_,
not determined.

In addition, the following were found casually at great depths in Loch
Ness: _Hydra_, _Limnaea peregra_, _Proales daphnicola_ and _Lynceus
affinis_.

The _pelagic region_ of the Scottish lakes is occupied by numerous
microscopic organisms, belonging to the Zooplankton and Phytoplankton.
Of the former group 30 species belonging to the Crustacea, Rotifera
and Protozoa were recorded in Loch Ness. Belonging to the second group
150 species were recorded, of which 120 were Desmids. Some of these
species of plankton organisms are almost universal in the Scottish
lochs, while others are quite local. Some of the species occur all the
year through, while others have only been recorded in summer or in
winter. The great development of Algae in the surface waters, called
"flowering of the water" (_Wasserblüthe_), was observed in August in
Loch Lomond; a distinct "flowering," due to Chlorophyceae, has been
observed in shallow lochs as early as July. It is most common in
August and September, but has also been observed in winter.

The plankton animals which are dominant or common, both over Scotland
and the rest of Europe, are:--

_Diaptomus gracilis._
_Daphnia kyalina._
_Diaphanosoma brachyurum._
_Leptodora kindtii._
_Conochilus unicornis._
_Asplanchna priodonta._
_Polyarthra platyptera._
_Anuraea cochlearis._
_Notholca longispina._
_Ceratium hirundinella._
_Asterionella._

All of these, according to Dr Lund, belong to the general plankton
association of the European plain, or are even cosmopolitan.

The Scottish plankton on the whole differs from the plankton of the
central European plateau, and from the cosmopolitan fresh-water
plankton, in the extraordinary richness of the Phytoplankton in
species of Desmids, in the conspicuous arctic element among the
Crustacea, in the absence or comparative rarity of the species
commonest in the general European plankton. Another peculiarity is the
local distribution of some of the Crustacea and many of the Desmids.

The derivation of the whole lacustrine population of the Scottish
lochs does not seem to present any difficulty. The abyssal forms have
been traced to the littoral zone without any perceptible
modifications. The plankton organisms are a mingling of European and
arctic species. The cosmopolitan species may enter the lochs by
ordinary migration. It is probable that if the whole plankton could be
annihilated, it would be replaced by ordinary migration within a few
years. The eggs and spores of many species can be dried up without
injury, and may be carried through the air as dust from one lake to
another; others, which would not bear desiccation, might be carried in
mud adhering to the feet of aquatic birds and in various other ways.
The arctic species may be survivors from a period when arctic
conditions prevailed over a great part of Europe. What are known as
"relicts" of a marine fauna have not been found in the Scottish
fresh-water lochs.

It is somewhat remarkable that none of the organisms living in
fresh-water lochs has been observed to exhibit the phenomenon of
phosphorescence, although similar organisms in the salt-water lochs a
few miles distant exhibit brilliant phosphorescence. At similar depths
in the sea-lochs there is usually a great abundance of life when
compared with that found in fresh-water lochs.

_Length, Depth, Area and Volume of Lakes._--In the following table will be found the length, depth, area and volume of some of the principal lakes of the world.[1] Sir John Murray estimates The volume of water in the 560 Scottish lochs recently surveyed at 7 cub. m., and the approximate volume of water in all the lakes of the world at about 2000 cub. m., so that this last number is but a small fraction of the volume of the ocean, which he previously estimated at 324 million cub. m. It may be recalled that the total rainfall on the land of the globe is estimated at 29,350 cub. m., and the total discharge from the rivers of the globe at 6524 cub. m.

BRITISH LAKES

+--------------------+-------+---------------+--------+-----------+
| |Length | Depth | Area | Volume in |
| | in | in | in | million |
| | Miles.| Feet. | sq. m. | cub. ft. |
+--------------------+-------+------+--------+--------+-----------+
|I. _England_-- | | Max. | Mean. | | |
| Windermere | 10.50 | 219 | 78.5 | 5.69 | 12,250 |
| Ullswater | 7.35 | 205 | 83 | 3.44 | 7,870 |
| Wastwater | 3.00 | 258 | 134.5 | 1.12 | 4,128 |
| Coniston Water | 5.41 | 184 | 79 | 1.89 | 4,000 |
| Crummock Water | 2.50 | 144 | 87.5 | 0.97 | 2,343 |
| Ennerdale Water | 2.40 | 148 | 62 | 1.12 | 1,978 |
| Bassenthwaite | | | | | |
| Water | 3.83 | 70 | 18 | 2.06 | 1,023 |
| Derwentwater | 2.87 | 72 | 18 | 2.06 | 1,010 |
| Haweswater | 2.33 | 103 | 39.5 | 0.54 | 589 |
| Buttermere | 1.26 | 94 | 54.5 | 0.36 | 537 |
|II. _Wales_-- | | | | | |
| Llyn Cawlyd | 1.62 | 222 | 109.1 | 0.18 | 941 |
| Llyn Cwellyn | 1.20 | 122 | 74.1 | 0.35 | 713 |
| Llyn Padarn | 2.00 | 94 | 52.4 | 0.43 | 632 |
| Llyn Llydaw | 1.11 | 190 | 77.4 | 0.19 | 409 |
| Llyn Peris | 1.10 | 114 | 63.9 | 0.19 | 344 |
| Llyn Dulyn | 0.31 | 189 | 104.2 | 0.05 | 156 |
|III. _Scotland_-- | | | | | |
| Ness | 24.23 | 754 | 433.02 | 21.78 | 263,162 |
| Lomond | 22.64 | 623 | 121.29 | 27.45 | 92,805 |
| Morar | 11.68 | 1017 | 284.00 | 10.30 | 81,482 |
| Tay | 14.55 | 508 | 199.08 | 10.19 | 56,550 |
| Awe | 25.47 | 307 | 104.95 | 14.85 | 43,451 |
| Maree | 13.46 | 367 | 125.30 | 11.03 | 38,539 |
| Lochy | 9.78 | 531 | 228.95 | 5.91 | 37,726 |
| Rannoch | 9.70 | 440 | 167.46 | 7.37 | 34,387 |
| Shiel | 17.40 | 420 | 132.73 | 7.56 | 27,986 |
| Arkaig | 12.00 | 359 | 152.71 | 6.24 | 26,573 |
| Earn | 6.46 | 287 | 137.83 | 3.91 | 14,421 |
| Treig | 5.10 | 436 | 207.37 | 2.41 | 13,907 |
| Shin | 17.22 | 162 | 51.04 | 8.70 | 12,380 |
| Fannich | 6.92 | 282 | 108.76 | 3.60 | 10,920 |
| Assynt | 6.36 | 282 | 101.10 | 3.10 | 8,731 |
| Quoich | 6.95 | 281 | 104.60 | 2.86 | 8,345 |
| Glass | 4.03 | 365 | 159.07 | 1.86 | 8,265 |
| Fionn (Carnmore) | 5.76 | 144 | 57.79 | 3.52 | 5,667 |
| Laggan | 7.04 | 174 | 67.68 | 2.97 | 5,601 |
| Loyal | 4.46 | 217 | 65.21 | 2.55 | 4,628 |
|IV. _Ireland_-- | | | | | |
| Neagh | 17 | 102 | 40 |153 | 161,000 |
| Erne (Lower) | 24 | 226 | 43 | 43 | 62,000 |
| Erne (Upper) | 13 | 89 | 10 | 15 | 5,000 |
| Corrib | 27 | 152 | 30 | 68 | 59,000 |
| Mask | 10 | 191 | 52 | 35 | 55,000 |
| Derg | 24 | 119 | 30 | 49 | 47,000 |
+--------------------+-------+---------------+--------+-----------+

EUROPEAN CONTINENTAL LAKES

+------------+-------+--------------+--------+------------+
| |Length | Depth | Area | Volume in |
| | in | in | in | million |
| | Miles.| Feet. | sq. m. | cub. ft. |
+------------+-------+------+-------+--------+------------+
| | | Max. | Mean. | | |
| Ladoga | 125 | 732 | 300 | 7000 | 43,200,000 |
| Onega | 145 | 740 | 200 | 3800 | 21,000,000 |
| Vener | 93 | 292 | 108 | 2149 | 6,357,000 |
| Geneva | 45 | 1015 | 506 | 225 | 3,175,000 |
| Vetter | 68 | 413 | 128 | 733 | 2,543,000 |
| Mjösen | 57 | 1483 | .. | 139 | 2,882,000 |
| Garda | 38 | 1124 | 446 | 143 | 1,766,000 |
| Constance | 42 | 827 | 295 | 208 | 1,711,000 |
| Ochrida | 19 | 942 | 479 | 105 | 1,391,000 |
| Maggiore | 42 | 1220 | 574 | 82 | 1,310,000 |
| Como | 30 | 1345 | 513 | 56 | 794,000 |
| Hornafvan | 7 | 1391 | 253 | 93 | 777,000 |
+------------+-------+--------------+--------+------------+

AFRICAN LAKES

+----------------+------+-------------+--------+-------------+
| |Length| Depth | Area | Volume in |
| | in | in | in | million |
| |Miles.| Feet. | sq. m. | cub. ft. |
+----------------+------+------+------+--------+-------------+
| | | Max. | Mean.| | |
| Victoria Nyanza| 200 | 240 | .. | 26,200 | 5,800,000 |
| Nyasa | 350 | 2580 | .. | 14,200 | 396,000,000 |
| Tanganyika | 420 | 2100 | .. | 12,700 | 283,000,000 |
+----------------+------+------+------+--------+-------------+

ASIATIC LAKES

+----------+-------+-------------+--------+------------+
| |Length | Depth | Area | Volume in |
| | in | in | in | million |
| | Miles.| Feet. | sq. m. | cub. ft. |
+----------+-------+------+------+--------+------------+
| | | Max. | Mean.| | |
| Aral | 265 | 222 | 52 | 24,400 | 43,600,000 |
| Baikal | 330 | 5413 | .. | 11,580 |274,000,000 |
| Balkash | 323 | 33 | .. | 7,000 | 4,880,000 |
| Urmia | 80 | 50 | 15 | 1,750 | 732,000 |
+----------+-------+------+------+--------+------------+

AMERICAN LAKES

+------------+-------+-------------+--------+-------------+
| |Length | Depth | Area | Volume in |
| | in | in | in | million |
| | Miles.| Feet. | sq. m. | cub. ft. |
+------------+-------+------+------+--------+-------------+
| | | Max. | Mean.| | |
| Superior | 412 | 1008 | 475 | 31,200 | 413,000,000 |
| Huron | 263 | 730 | 250 | 23,800 | 166,000,000 |
| Michigan | 335 | 870 | 325 | 22,450 | 203,000,000 |
| Erie | 240 | 210 | 70 | 9,960 | 19,500,000 |
| Ontario | 190 | 738 | 300 | 7,240 | 61,000,000 |
| Titicaca | 120 | 924 | 347 | 3,200 | 30,900,000 |
+------------+-------+------+------+--------+-------------+

NEW ZEALAND LAKES

+--------------+-------+-------------+--------+-----------+
| |Length | Depth | Area | Volume in |
| | in | in | in | million |
| | Miles.| Feet. | sq. m. | cub. ft. |
+--------------+-------+------+------+--------+-----------+
| | | Max. | Mean.| | |
| Taupo | 25 | 534 | 367 | 238.0 | 2,435,000 |
| Wakatipu | 49 | 1242 | 707 | 112.3 | 2,205,000 |
| Manapouri | 19 | 1458 | 328 | 56.0 | 512,000 |
| Rotorua | 7.5 | 120 | 39 | 31.6 | 34,000 |
| Waikarimoana | 7.25 | 846 | 397 | 14.7 | 166,000 |
| Wairaumoana | 5.25 | 375 | 175 | 6.1 | 30,000 |
| Rotoiti | 10.7 | 230 | 69 | 14.2 | 27,000 |
+--------------+-------+------+------+--------+-----------+

AUTHORITIES.--F. A. Forel, "Handbuch der Seenkunde: allgemeine
Limnologie," _Bibliothek geogr. Handbücher_ (Stuttgart, 1901), _Le
Léman, monographie limnologique_ (3 vols., Lausanne, 1892-1901); A.
Delebecque, _Les Lacs français_, text and plates (Paris, 1898); H. R.
Mill, "Bathymetrical Survey of the English Lakes," _Geogr. Journ._
vol. vi. pp. 46 and 135 (1895); Jehu, "Bathymetrical and Geological
Study of the Lakes of Snowdonia," _Trans. Roy. Soc. Edin._ vol. xl. p.
419 (1902); Sir John Murray and Laurence Pullar, "Bathymetrical Survey
of the Freshwater Lochs of Scotland," _Geogr. Journ._ (1900 to 1908,
re-issued in six volumes, Edinburgh, 1910); W. Halbfass, "Die
Morphometrie der europäischen Seen," _Zeitschr. Gesell. Erdkunde
Berlin_ (Jahrg. 1903, p. 592; 1904, p. 204); I. C. Russell, _Lakes of
North America_ (Boston and London, 1895); O. Zacharias,
"Forschungsberichte aus der biologischen Station zu Plön" (Stuttgart);
F. E. Bourcart, _Les Lacs alpins suisses: étude chimique et physique_
(Geneva, 1906); G. P. Magrini, _Limnologia_ (Milan, 1907). (J. Mu.)

FOOTNOTE:

[1] Divergence between certain of these figures and those quoted
elsewhere in this work may be accounted for by the slightly different
results arrived at by various authorities.

LAKE CHARLES, a city of Louisiana, U.S.A., capital of Calcasieu Parish, 30 m. from the Gulf of Mexico and about 218 m. (by rail) W. of New Orleans. Pop. (1889) 838, (1890) 3442, (1900) 6680 (2407 negroes); (1910) 11,449. It is served by the Louisiana & Texas (Southern Pacific System), the St Louis, Watkins & Gulf, the Louisiana & Pacific and the Kansas City Southern railways. The city is charmingly situated on the shore of Lake Charles, and on the Calcasieu river, which with some dredging can be made navigable for large vessels for 132 m. from the Gulf. It is a winter resort. Among the principal buildings are a Carnegie library, the city hall, the Government building, the court house, St Patrick's sanatorium, the masonic temple and the Elks' club. Lake Charles is in the prairie region of southern Louisiana, to the N. of which, covering a large part of the state, are magnificent forests of long-leaf pine, and lesser lowland growths of oak, ash, magnolia, cypress and other valuable timber. The Watkins railway extending to the N.E. and the Kansas City Southern extending to the N.W. have opened up the very best of the forest. The country to the S. and W. is largely given over to rice culture. Lake Charles is the chief centre of lumber manufacture in the state, and has rice mills, car shops and an important trade in wool. Ten miles W. are sulphur mines (product in 1907 about 362,000 tons), which with those of Sicily produce a large part of the total product of the world. Jennings, about 34 m. to the E., is the centre of oil fields, once very productive but now of diminishing importance. Welsh, 23 m. E., is the centre of a newer field; and others lie to the N. Lake Charles was settled about 1852, largely by people from Iowa and neighbouring states, was incorporated as a town in 1857 under the name of Charleston and again in 1867 under its present name, and was chartered as a city in 1886. The city suffered severely by fire in April 1910.

LAKE CITY, a town and the county-seat of Columbia county, Florida, U.S.A., 59 m. by rail W. by S. of Jacksonville. Pop. (1900) 4013, of whom 2159 were negroes; (1905) 6509; (1910) 5032. Lake City is served by the Atlantic Coast Line, the Seaboard Air Line and the Georgia Southern & Florida railways. There are ten small lakes in the neighbourhood, and the town is a winter and health resort. It is the seat of Columbia College (Baptist, 1907); the Florida Agricultural College was opened here in 1883, became the university of Florida in 1903, and in 1905 was abolished by the Buckman Law. Vegetables and fruits grown for the northern markets, sea-island cotton and tobacco are important products of the surrounding country, and Lake City has some trade in cotton, lumber, phosphates and turpentine. The town was first settled about 1826 as Alligator; it was incorporated in 1854; adopted the present name in 1859; and in 1901, with an enlarged area, was re-incorporated.

LAKE DISTRICT, in England, a district containing all the principal English lakes, and variously termed the Lake Country, Lakeland and "the Lakes." It falls within the north-western counties of Cumberland, Westmorland and Lancashire (Furness district), about one-half being within the first of these. Although celebrated far outside the confines of Great Britain as a district of remarkable and strongly individual physical beauty, its area is only some 700 sq. m., a circle with radius of 15 m. from the central point covering practically the whole. Within this circle, besides the largest lake, Windermere, is the highest point in England, Scafell Pike; yet Windermere is but 10½ m. in length, and covers an area of 5.69 sq. m., while Scafell Pike is only 3210 ft. in height. But the lakes show a wonderful variety of character, from open expanse and steep rock-bound shores to picturesque island-groups and soft wooded banks; while the mountains have always a remarkable dignity, less from the profile of their summits than from the bold sweeping lines of their flanks, unbroken by vegetation, and often culminating in sheer cliffs or crags. At their feet, the flat green valley floors of the higher elevations give place in the lower parts to lovely woods. The streams are swift and clear, and numerous small waterfalls are characteristic of the district. To the north, west and south, a flat coastal belt, bordering the Irish Sea, with its inlets Morecambe Bay and Solway Firth, and broadest in the north, marks off the Lake District, while to the east the valleys of the Eden and the Lune divide it from the Pennine mountain system. Geologically, too, it is individual. Its centre is of volcanic rocks, complex in character, while the Coal-measures and New Red Sandstone appear round the edges. The district as a whole is grooved by a main depression, running from north to south along the valleys of St John, Thirlmere, Grasmere and Windermere, surmounting a pass (Dunmail Raise) of only 783 ft.; while a secondary depression, in the same direction, runs along Derwentwater, Borrowdale, Wasdale and Wastwater, but here Sty Head Pass, between Borrowdale and Wasdale, rises to 1600 ft. The centre of the 15-m. radius lies on the lesser heights between Langstrath and Dunmail Raise, which may, however, be the crown of an ancient dome of rocks, "the dissected skeleton of which, worn by the warfare of air and rain and ice, now alone remains" (Dr H. R. Mill, "Bathymetrical Survey of the English Lakes," _Geographical Journal_, vi. 48). The principal features of the district may be indicated by following this circle round from north, by west, south and east.

The river Derwent (q.v.), rising in the tarns and "gills" or "ghylls"
(small streams running in deeply-grooved clefts) north of Sty Head
Pass and the Scafell mass flows north through the wooded Borrowdale
and forms Derwentwater and Bassenthwaite. These two lakes are in a
class apart from all the rest, being broader for their length, and
quite shallow (about 18 ft. average and 70 ft. maximum), as distinct
from the long, narrow and deep troughs occupied by the other chief
lakes, which average from 40 to 135 ft. deep. Derwentwater (q.v.),
studded with many islands, is perhaps the most beautiful of all.
Borrowdale is joined on the east by the bare wild dale of Langstrath,
and the Greta joins the Derwent immediately below Derwentwater; the
town of Keswick lying near the junction. Derwentwater and
Bassenthwaite occupy a single depression, a flat alluvial plain
separating them. From Seatoller in Borrowdale a road traverses
Honister Pass (1100 ft.), whence it descends westward, beneath the
majestic Honister Crags, where green slate is quarried, into the
valley containing Buttermere (94 ft. max. depth) and Crummock Water
(144 ft.), drained by the Cocker. Between this and the Derwent valley
the principal height is Grasmoor (2791 ft.); southward a steep narrow
ridge (High Style, 2643) divides it from Ennerdale, containing
Ennerdale Water (148 ft. max. depth), which is fed by the Liza and
drained by the Ehen. A splendid range separates this dale from Wasdale
and its tributary Mosedale, including Great Gable (2949 ft.), Pillar
(2927), with the precipitous Pillar Rock on the Ennerdale flank and
Steeple (2746). Wasdale Head, between Gable and the Scafell range, is
peculiarly grand, with dark grey screes and black crags frowning above
its narrow bottom. On this side of Gable is the fine detached rock,
Napes Needle. Wastwater, 3 m. in length, is the deepest lake of all
(258 ft.), its floor, like those of Windermere and Ullswater, sinking
below sea-level. Its east shore consists of a great range of screes.
East of Wasdale lies the range of Scafell (q.v.), its chief points
being Scafell (3162 ft.), Scafell Pike (3210), Lingmell (2649) and
Great End (2984), while the line is continued over Esk Hause Pass
(2490) along a fine line of heights (Bow Fell, 2960; Crinkle Crags,
2816), to embrace the head of Eskdale. The line then descends to
Wrynose Pass (1270 ft.), from which the Duddon runs south through a
vale of peculiar richness in its lower parts; while the range
continues south to culminate in the Old Man of Coniston (2633) with
the splendid Dow Crags above Goats Water. The pleasant vale of Yewdale
drains south to Coniston Lake (5½ m. long, 184 ft. max. depth), east
of which a lower, well-wooded tract, containing two beautiful lesser
lakes, Tarn Hows and Esthwaite Water, extends to Windermere (q.v.).
This lake collects waters by the Brathay from Langdale, the head of
which, between Bow Fell and Langdale Pikes (2401 ft.), is very fine;
and by the Rothay from Dunmail Raise and the small lakes of Grasmere
and Rydal Water, embowered in woods. East of the Rothay valley and
Thirlmere lies the mountain mass including Helvellyn (3118 ft.),
Fairfield (2863) and other points, with magnificent crags at several
places on the eastern side towards Grisedale and Patterdale. These
dales drain to Ullswater (205 ft. max., second to Windermere in area),
and so north-east to the Eden. To the east and south-east lies the
ridge named High Street (2663 ft.), from the Roman road still
traceable from south to north along its summit, and sloping east again
to the sequestered Hawes Water (103 ft. max.), a curiously shaped lake
nearly divided by the delta of the Measand Beck. There remains the
Thirlmere valley. Thirlmere itself was raised in level, and adapted by
means of a dam at the north end, as a reservoir for the water-supply
of Manchester in 1890-1894. It drains north by St John's Vale into the
Greta, north of which again rises a mountain-group of which the chief
summits are Saddleback or Blencathra (2847 ft.) and the graceful peak
of Skiddaw (3054). The most noteworthy waterfalls are--Scale Force
(Dano-Norwegian _fors_, _foss_), beside Crummock, Lodore near
Derwentwater, Dungeon Gill Force, beside Langdale, Dalegarth Force in
Eskdale, Aira near Ullswater, sung by Wordsworth, Stock Gill Force and
Rydal Falls near Ambleside.

The principal centres in the Lake District are Keswick (Derwentwater),
Ambleside, Bowness, Windermere and Lakeside (Windermere), Coniston and
Boot (Eskdale), all of which, except Ambleside and Bowness (which
nearly joins Windermere) are accessible by rail. The considerable
village of Grasmere lies beautifully at the head of the lake of that
name; and above Esthwaite is the small town of Hawkshead, with an
ancient church, and picturesque houses curiously built on the
hill-slope and sometimes spanning the streets. There are regular
steamer services on Windermere and Ullswater. Coaches and cars
traverse the main roads during the summer, but many of the finest
dales and passes are accessible only on foot or by ponies. All the
mountains offer easy routes to pedestrians, but some of them, as
Scafell, Pillar, Gable (Napes Needle), Pavey Ark above Langdale and
Dow Crags near Coniston, also afford ascents for experienced climbers.

This mountainous district, having the sea to the west, records an
unusually heavy rainfall. Near Seathwaite, below Styhead Pass, the
largest annual rainfall in the British Isles is recorded, the average
(1870-1899) being 133.53 in., while 173.7 was measured in 1903 and
243.98 in. in 1872. At Keswick the annual mean is 60.02, at Grasmere
about 80 ins. The months of maximum rainfall at Seathwaite are
November, December and January and September.

Fish taken in the lakes include perch, pike, char and trout in
Windermere, Ennerdale, Bassenthwaite, Derwentwater, &c., and the
gwyniad or fresh-water herring in Ullswater. The industries of the
Lake District include slate quarrying and some lead and zinc mining,
and weaving, bobbin-making and pencil-making.

Setting aside London and Edinburgh, no locality in the British Isles
is so intimately associated with the history of English literature as
the Lake District. In point of time the poet whose name is first
connected with the region is Gray, who wrote a journal of his tour in
1769. But it was Wordsworth, a native of Cumberland, born on the
outskirts of the Lake District itself, who really made it a Mecca for
lovers of English poetry. Out of his long life of eighty years, sixty
were spent amid its lakes and mountains, first as a schoolboy at
Hawkshead, and afterwards as a resident at Grasmere (1799-1813) and
Rydal Mount (1813-1850). In the churchyard of Grasmere the poet and
his wife lie buried; and very near to them are the remains of Hartley
Coleridge (son of the poet), who himself lived many years at Keswick,
Ambleside and Grasmere. Southey, the friend of Wordsworth, was a
resident of Keswick for forty years (1803-1843), and was buried in
Crosthwaite churchyard. Samuel Taylor Coleridge lived some time at
Keswick, and also with the Wordsworths at Grasmere. From 1807 to 1815
Christopher North (John Wilson) was settled at Windermere. De Quincey
spent the greater part of the years 1809 to 1828 at Grasmere, in the
first cottage which Wordsworth had inhabited. Ambleside, or its
environs, was also the place of residence of Dr Arnold (of Rugby), who
spent there the vacations of the last ten years of his life; and of
Harriet Martineau, who built herself a house there in 1845. At Keswick
Mrs Lynn Linton was born in 1822. Brantwood, a house beside Coniston
Lake, was the home of Ruskin during the last years of his life. In
addition to these residents or natives of the locality, Shelley,
Scott, Nathaniel Hawthorne, Clough, Crabb Robinson, Carlyle, Keats,
Tennyson, Matthew Arnold, Mrs Hemans, Gerald Massey and others of less
reputation made longer or shorter visits, or were bound by ties of
friendship with the poets already mentioned. The Vale of St John, near
Keswick, recalls Scott's _Bridal of Triermain_. But there is a deeper
connexion than this between the Lake District and English letters.
German literature tells of several literary schools, or groups of
writers animated by the same ideas, and working in the spirit of the
same principles and by the same poetic methods. The most notable
instance--indeed it is almost the only instance--of the kind in
English literature is the Lake School of Poets. Of this school the
acknowledged head and founder was Wordsworth, and the tenets it
professed are those laid down by the poet himself in the famous
preface to the edition of _The Lyrical Ballads_ which he published in
1800. Wordsworth's theories of poetry--the objects best suited for
poetic treatment, the characteristics of such treatment and the choice
of diction suitable for the purpose--may be said to have grown out of
the soil and substance of the lakes and mountains, and out of the
homely lives of the people, of Cumberland and Westmoreland.

See CUMBERLAND, LANCASHIRE, WESTMORLAND. The following is a selection
from the literature of the subject: Harriet Martineau, _The English
Lakes_ (Windermere, 1858); Mrs Lynn Linton, _The Lake Country_
(London, 1864); E. Waugh, _Rambles in the Lake Country_ (1861) and _In
the Lake Country_ (1880); W. Knight, _Through the Wordsworth Country_
(London, 1890); H. D. Rawnsley, _Literary Associations of the English
Lakes_ (2 vols., Glasgow, 1894) and _Life and Nature of the English
Lakes_ (Glasgow, 1899); Stopford Brooke, _Dove Cottage, Wordsworth's
Home from 1800 to 1808_; A. G. Bradley, _The Lake District, its
Highways and Byeways_ (London, 1901); Sir John Harwood, _History of
the Thirlmere Water Scheme_ (1895); for mountain-climbing, Col. J.
Brown, _Mountain Ascents in Westmorland and Cumberland_ (London,
1888); Haskett-Smith, _Climbing in the British Isles_, part, i.; Owen
G. Jones, _Rock-climbing in the English Lake District_, 2nd ed. by W.
M. Crook (Keswick, 1900).

LAKE DWELLINGS, the term employed in archaeology for habitations constructed, not on the dry land, but within the margins of lakes or creeks at some distance from the shore.

The villages of the Guajiros in the Gulf of Maracaibo are described by Goering as composed of houses with low sloping roofs perched on lofty piles and connected with each other by bridges of planks. Each house consisted of two apartments; the floor was formed of split stems of trees set close together and covered with mats; they were reached from the shore by dug-out canoes poled over the shallow waters, and a notched tree trunk served as a ladder. The custom is also common in the estuaries of the Orinoco and Amazon. A similar system prevails in New Guinea. Dumont d'Urville describes four such villages in the Bay of Dorei, containing from eight to fifteen blocks or clusters of houses, each block separately built on piles, and consisting of a row of distinct dwellings. C. D. Cameron describes three villages thus built on piles in Lake Mohrya, or Moria, in Central Africa, the motive here being to prevent surprise by bands of slave-catchers. Similar constructions have been described by travellers, among the Dyaks of Borneo, in Celebes, in the Caroline Islands, on the Gold Coast of Africa, and in other places.

Hippocrates, writing in the 5th century B.C., says of the people of the Phasis that their country is hot and marshy and subject to frequent inundations, and that they live in houses of timber and reeds constructed in the midst of the waters, and use boats of a single tree trunk. Herodotus, writing also in the 5th century B.C., describes the people of Lake Prasias as living in houses constructed on platforms supported on piles in the middle of the lake, which are approached from the land by a single narrow bridge. Abulfeda the geographer, writing in the 13th century, notices the fact that part of the Apamaean Lake was inhabited by Christian fishermen who lived on the lake in wooden huts built on piles, and Sir John Lubbock (Lord Avebury) mentions that the Rumelian fishermen on Lake Prasias "still inhabit wooden cottages built over the water, as in the time of Herodotus."