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Size of England.

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Such are all the latitudes and longitudes of places to be found in the Philosophical Transactions, or at least the greatest number of them. There is one other paper on a subject somewhat connected with this, which it may be proper to notice. Dr. Grew, from a very simple calculation, estimates the number of acres, in England, at 46,080,000. He then compares the size of England and Holland, and observes, that if England were as populous in proportion to its

(a) Phil. Trans. 1791. Vol. LXXXI. p. 236.

(6) The longitudes are from the observatory of Copenhagen. Phil. Trans. 1794. Vol. LXXXIV. p. 43.

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size as Holland, it would contain 110 millions of inhabitants.* But Dr. Grew's estimate is obviously too great. He makes the length of England, from Berwick to the southernmost point, 400 miles, whereas it certainly does not exceed 350. The breadth of England, where greatest, he makes 360 miles, whereas it cannot be reckoned more than 300, if it amounts to that quantity.

of maps.

II. CONSTRUCTION OF MAPS. The construction of maps belongs to geometry, Construction depending upon the various methods of projecting a sphere upon a plane surface. The method most commonly used for maps is what is called the stereographic projection, in which the eye is usually conceived to be in the surface of the sphere, opposite to that which is delineated. In maps of this construction, the meridians cut the circles of latitude perpendicularly, which they ought to do; but the central parts of a map of this kind, when it represents a considerable tract of country, for example, a hemisphere, are contracted greatly below their proper size. Rectilinear maps were very early adopted, in which the meridians were described parallel to each other, and the degrees of longitude and latitude every where equal the rhumbs were consequently right lines, and hereby it was thought that the courses or bearings of places would be more easily determined. But such maps were soon found insufficient for nautical purposes, as giving results totally erroneous. The first step to improve them was made by Gerard Mercator, who published a map about the year Mercator's 1550, in which the degrees of latitude were increased from the equator to the pole. But he did not show upon what principle he had constructed these maps. About the year 1590, Mr. Edward Wright discovered the true principles on which such charts should be constructed, and communicated his discovery to one Iodocus Hondius, an engraver, who, contrary to his engagement, published i☛ as his own. This induced Mr. Wright, in the year 1599, to communicate his method of construction to the public, in his book, entitled Correction of Errors in Navigation. In the preface to this work, he explains the share which Mercator had in this important invention, and gives an account, likewise, of the treacherous conduct of Hondius. This invention of Wright is perfect in its kind, and is of the utmost importance to navigators.

The greater number of maps seem to be laid down according to no fixed principle of projection, and are often very erroneous, as far as the distances between places is concerned. On this account Mr. Murdoch, in a paper which he published in the Philosophical Transactions, proposed a new method of projecting maps, in which these errors are the least possible. It consisted in finding a conical surface, equal to the spherical surface, which was to be given, and then, in spreading out this conical surface into a plane. He gives the rules for finding the conical surface, and for constructing maps accurately,

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projection.

Rate at which camels travel.

Hydrology.

Zirchnitzer
Sea

according to his principles.* There can be no doubt, that maps constructed on this principle would, in many cases, be preferable to the common ones; though I do not recollect ever to have seen any map actually made according to the rules laid down by Murdoch.

It may be worth while to mention here an ingenious method proposed by Major Rennel, for determining distances in those parts of Africa and Asia, where more accurate methods cannot be had recourse to. In these countries long journies are performed by means of camels, between places at a very great distance from each other. Now these caravans always travel the same number of hours every day, and Major Rennel has shown, that camels always travel at the rate of 2 miles in the hour. Hence, knowing the number of hours travelled, or even the number of days, it is easy to determine the distance. And if the bearings have been taken with a pocket compass, the position of the places on the globe may be determined with considerable accuracy.†

III. HYDROLOGY. The papers on this subject, in the Philosophical Transactions, are only two: the first giving an account of a remarkable lake in Carniola; the other, of the falls of Niagara.

In Carniola there is a lake called the Zirchnitzer Sea, two German miles long and one broad. In the month of June it sinks under ground, through a great number of holes, which empty themselves in succession. At this period, the inhabitants in the neighbourhood are employed in fishing, and a vast quantity of fish are caught at the different holes. The fish in the lake are of three kinds, namely, the eel pout, the tench, and the pike, all of which grow to a large size. The lake also contains many crabs; but they do not constitute an agreeable article of food. While the lake is dry, the soil produces a fine crop of grass, which is cut down for hay. In some parts of it millet is sown, and a considerable crop obtained. In the month of September, the water rushes back again through the holes with great impetuosity, and the lake is restored to its original size. This extraordinary alternation in this lake is accounted for in the following manner: the country is hilly, and the lake is surrounded with rising grounds. It has no visible exit, yet seven rivulets empty themselves into it. By subterraneous channels, it communicates with two lakes concealed underground, the one situated below, the other above its own level. Into the first it empties itself by means of the holes in its bottom. From the second, it receives a supply equal to its waste, which prevents it from sinking underground during the winter. From the lowest lake a considerable river runs. In the summer, the uppermost lake not being fed as usual by rain, becomes smaller, and ceases to supply the Zirchnitzer Sea with water. The waste of this lake, therefore, being greater than the supply, it is drained in consequence, and dis

*Phil. Trans. 1758. Vol. L. p. 553.

+ Phil. Trans. 1791. Vol. LXXXI. p.. 129.

appears. When the uppermost lake is restored to its usual size, it affords the proper quantity of water; hence the lowest lake swells, and at last forces part of its contents through the holes into the open air, and thus restores the Zirchnitzer Sea to its original size.*

The falls of Niagara were measured in the year 1722, by order of the gover- Falls of Nianor of Canada, by means of a plumb-line, and were found to be 156 French ara. feet, which amounts to 1764 English feet.†

IV. TOPOGRAPHY. The countries and people, of which an account is given Topography in the Philosophical Transactions, arc, Hudson's Bay, the North American Indians, the Patagonians, the Falkland Islands, and Thibet.

1. Mr. Wales was sent out to Hudson's Bay, by the Royal Society, as a Hudson's Ba proper station for observing the transit of Venus over the sun's disk, in 1769. He continued in that country for 13 months; and, after his return, a very entertaining account of the climate, soil, and mode of living, with some observations on the inhabitants, was published by him in the Philosophical Transactions. The place where he wintered was at the Factory, on Churchill river, in north latitude 58° 55', west longitude 94° 50%. The following are the most important observations contained in this paper: on his approaching the coast the vessel was visited by some Eskimaux, in their boat, whom he praises highly for the excellence of their dispositions, and their skill in all the arts which they practised. The sea at that time was full of islands of ice, and he had an opportunity of ascertaining that the green-coloured ice, contrary to the opinion at that time received, was fresh, and not salt; provided sufficient care was taken to wash it from the salt water in which it was swimming, before examining it. The islands of ice moved with considerable velocity, and, as they went to the south, they were not long able to resist the united action of the solar rays and the heat of the sea, but speedily melted into water.

The atmosphere was usually hazy, and Mr. Wales observed with surprise, that the islands of ice, when seen at a distance, appeared considerably elevated, though when they got near them they were found to be scarcely raised above the level of the sea. When they approached the coast, the land was seen distinctly from the deck, but from the mast-head it was quite invisible. Mr. Wales was so surprised at this fact, that he went to the mast-head, and verified it himself. The country all round the factory for several miles is rocky, or composed of loose sand; the soil poor, and utterly unfit for every kind of corn except oats. There were many firs about 20 feet high, but no other trees,

*Brown. Phil. Trans. 1669. Vol. IV. p. 1080; and J. Weichard Valvasar. Ibid. 1687. Vol. XVL p. 411.

† Paul Dudley. Phil. Trans. 1722. Vol. XXXII. p. 69.

though the country was covered with bushes, consisting of dwarf willows and birches. There were many gooseberry and black currant bushes.

The country abounds with a prodigious number of birds, geese, ducks, partridges, &c., which come in succession, and supply the inhabitants with the greatest part of their food. During summer there are three insects which are remarkably troublesome; these are the moschetto; a kind of small fly called sand fly, which comes in such prodigious swarms as to fill the whole air, and to be exceedingly troublesome; and a very large fly, like the English flesh fly, which, when it lights on any part of the body, always draws blood.

The ground was covered with snow by the middle of October. In January the cold became very intense; the beams of their houses were continually cracking with a very loud noise, in consequence of the expansion of the frost, and the rocks split with a prodigious explosion. The wood of their beds was covered with a thick coat of ice, and brandy exposed to the open air soon became solid. The first thaw appeared on the 19th March, for a few minutes at noon, and on the 26th of March it thawed in reality. By the 23d of April, the ground was bare of snow in many places, and spring was begun by the end of that month. The month of May was of a pleasant temperature, neither too hot nor too cold. On the 16th of June the ice in the river broke up and went to sea, which enabled the inhabitants to begin their fishing pursuits. Great numbers of salmon were caught, and a fish which Mr. Wales calls kepling, and which he describes as the most delicate of all fish, far exceeding in flavour every other. On the 22d of January, the coldest day, the thermometer stood at 45° below zero, and on the third of July, which was the hottest day, it stood at S0°; so that the range of temperature in this climate amounts to 125o. In England, the range of temperature rarely exceeds 80°, and has scarcely ever been observed more than 100°.

The inhabitants of the country are all thin, and rather tall; they are copper coloured, with wide mouths, thick lips, and lank black hair. They appear rather of a melancholic temperament, as is the case with most rude nations; but they are friendly, good natured, honest, and hospitable. They lead a wandering life, and depend, for their subsistence, on hunting. They believe in two superior beings, a good and a bad, and pay a sort of worship to both.

Mr. Wales observed several marble rocks in the country, and specimens of copper and copper ore. He mentions, also, different kinds of pyrites and micas. The atmosphere is never clear for 24 hours together; there is a perpetual haze round the horizon, which gives occasion to two red circles of light, which make their appearance before sun-rise. The aurora borealis is not to be compared, in point of brightness, with what is often seen in England.*

* Phil. Trans. 1770. Vol. LX. p. 100.

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