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B.

.

.

1 pint (36.459 cub. inch.)
of the mineral water.
A.

contains Carbonate of Lime

6.0630 8.2507 Sulphate of Lime

9.8904 8.3064 Potassa

1.3549 1.1382 Soda

15.5779 17.1761 Magnesia

20.8704 21.1920 Nitrate of Magnesia

2.6551 traces Chloride of Magnesium

19.6909 26.3169 Silica

0.5033 0.9210 Alumina

0.5721 0.3938 Extractive matter

77.1780 gr.

83.6951 gr. Carbonic Acid Gas/ at 51° at the temp. $2.786 cu. in, 3.306 Atmospheric Air of the wells. 10.611 cu.in. 0.658 Specific Gravity, at 60° Fah.

1.00737 1.00897 1

ADOLPHUS WALCKER.
German Spa, Brighton,
Feb. 28, 1829.

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A Letter to Mr. Baily, admitting his undisputed Claim

to a Theorem relating to Survivorships. By a Corre

spondent. Dear Sir, I have been thinking, that, as an attempt has been made to direct the public attention to the oversight which I acknowledged to you the moment that I was aware of it, it might be right that I should ask you, whether there was any form, or any channel, by which you would like that I should publicly admit your undisputed claim to the discovery which I have lately printed in capitals as my own : and to assure you, that you cannot be more willing to point out such a proceeding than I should be to comply with your wishes.

I have certainly given you an advantage, in printing, as a conspicuous part of my paper, a remark which you had only thought worthy of being inserted in a note; and for the circumstance has been a little unlucky, not from any censure that may have been passed on me, as not having read every note even in the best book relating to the general subject of my essay; and still less from the contemptible sus

myself, picion of my having made a childish attempt to deck myself in borrowed plumes, and then to hold them so high that the slightest breath would blow them away: but because the occurrence tends to divert the attention of a reader from the essential subject of my essay; which, you may have observed, is, first to establish the superior convenience of a good formula in preference to all tables formed from a limited observation, for all ordinary cases of the valuation of annuities ; that is, between the ages of ten and seventy: and, secondly, to show, as I may hereafter do still more fully, that a uniformly increasing decrement of survivors, throughout the middle of life, will afford a value of mortality sufficiently near to the results of tables the most discordant among themselves, provided that the rate of increase be properly adjusted to the table.

I am, dear Sir,

Your faithful and obedient servant, Waterloo Place, 1 Feb, 1829.

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On the Atmospheric Influence of Woods. The effects produced on climate, by the preservation or destruction of forests, is an interesting subject of inquiry, which has sometimes engaged the attention not only of philosophers but of legislators. In France, about forty years ago, some alarm was created on account of the rapid cutting down of woods which had then changed owners, or were less carefully protected than they had formerly been. Where wood forms a great part of the fuel of a country, a strong motive will always exist for the planting of trees, and for guarding against their wasteful removal. But another evil than the deficiency of firewood, was then apprehended. It was contended by Cadet de Vaux, and other writers, that the great droughts experienced in some districts, were caused by the absence of the trees, which used to attract the clouds, and thus conduct to the earth those fertilizing showers, which reward the labours of the husbandman with an abundant harvest. Amidst the agitations of the Revolution, the complaints of these writers were listened to, and their representations were more than once brought under the consideration of the Convention and

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the Council of Five Hundred. We do not precisely recollect what legislative measures were adopted; but we believe, among other things, the sale of the National Forests was stopped. However, it does not appear that what was then done, though it may have saved some of the property in the possession of the state, had any important effect on the whole. Indeed it will be seen from what follows, that since that period, the woods of France have sustained a considerable diminution, equal in extent to the difference between 4 and is of the territory. ,!1

» ( )( . In the mean time, the investigation of this interesting subject has not been neglected. The attention of naturalists and men of science in the Netherlands was, in the course of last year, called to the alterations produced in the physical state of countries, by the destruction of forests, in consequence of prize for the investigation of this important question being offered by the Royal Philosophical Society of Brussels. The essay which obtained the prize, was written in French by M. A. Moreau de Jonnes, a staff-officer in the army. It appears that the author does not altogether concur with M. Cadet de Vaux; but we have not seen the original, and the following account has reference to a German translation, by M. Widenmann; Professor of Natural History, at Tubingen. In Germany, where great importance is attached to the subject, the work of M. Moreau de Jonnes has been, upon the whole, very favourably noticed by the reviewers of that country, and we have taken the liberty to make use of some of their observations.

'1 -The author begins with a statistical account of certain woods and forests, from which, though he complains of the insufficiency of the documents available for his calculation, at least -one conclusion, which appears pretty well founded, may be drawn. According to the data here made use of, the woods in France amounted, in 1750, to more than a fourth of the surface of the whole country ; in 1788, to a seventh ji and in 1814,, to not quite a twelfth of that surface, Thus, within sixty-four years, 5000 square miles of the woods of France must have disappeared. In England, according to the author's estimate, the woods amount to only one twenty-third of the surface.

SO Chap. I.-Influence of Woods on the Temperature of Countries.

11.11') Woods lower the temperature. In the author's opinion they have this effect, because, on account of their dark colour, they reflect back few rays of light and heat to the atmosphere, and because they keep the soil damp, and therefore render more heat necessary to promote evaporation. But whether the difference of the mean temperature between Rome and Massachusetts, which, in the same geographical latitude, amounts to 64 cents of a degree, is to be attributed almost entirely to the woods, does not appear so easily demonstrable. That woods on mountains have a great influence in intercepting and beating down vapours is very probable; but the author's assertion that the increased condensation of vapours has for its consequence a greater absorption of heat, is unsupported by proof.' It must also be observed, that though woods diminish temperature, and though the author proves this fact by práctical observations, yet the experiments as cited by him are so detached, as to leave room for considerable objection. Vienna and Troyes have not a difference of temperature, merely because eastern countries are generally more covered with wood, but also because the site of Vienna is 250 feet higher, and lies nearer high mountains than Troyes. Again, Berlin is colder than Leyden in Holland, not altogether in consequence of Brandenburg being a woody country, bat also because it is exposed to the cold east wind. The translator points out the difference of height, which in the original is unattended to.

The author shews from historical comparisons, that the clearing away of woods makes the temperature of countries warmer. Whether the proofs that he adduces for this purpose are all quite convincing, we cannot positively affirm, though the 'fact itself is true; for France is no more deprived of its woods than England. If, then, there be, at present, nearly the same degree of heat in London and Paris, while, in the time of Tacitus, Gaul must have been colder, it is not quite clear why this contrary influence should proceed from the same cause. But it is also doubtful whether Tacitus would not even "now, if he Had ho assistance from the thermometer, call London milder ochwe it lob - ytrve, ti I need

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than Paris, because severe winters occur less often in the former than in the latter city. But though the details of these comparisons may occasionally be uncertain, and more particularly those which relate to the question, whether a difference of temperature in former times ought to be attributed solely to the great abundance of woods and forests, yet a collection of the accounts of a greater degree of cold having heretofore existed, is doubtless very important. There can be but few to whom it will not be interesting to learn how much the cold of winter, especially in the south of Europe, has diminished.

Chap. II.-Influence on the quantity of Rain. The author here brings forward some observations to prove that more rain falls on the sea-coast than in inland districts, and that, moreover, when chains of mountains run parallel to the sea-shore, the sides next the sea receive more rain than their opposite sides. In reference

In reference to woods, however, the author supposes that he may lay it down as a fact confirmed by observation that wood-lands in flat countries do not perceptibly increase the quantity of rain; but that woods on mountains have a perceptible influence in producing that effect. He thereupon founds the conclusion, that if mountains are planted with trees, the quantity of rain in their vicinity will be increased, and that the progressive diminution of rain in the South of Europe is to be ascribed to the destruction of the mountain woods. But the author does not appear to have been sufficiently careful in ascertaining what are the places in which the rain has diminished. It has not diminished in all parts of the south of Europe; for Flaugergues has found that the quantity of rain has considerably increased at Viviers, in the south of France, since 1778. The Milanese Ephemerides indicate the same thing for Milan, and all the assertions of this kind require further demonstration.

Cuar, III. Of the Influence of Woods on the Humidity of the

Atmosphere. Here the author describes among other things an interesting experiment with the hygrometer, according to which the humidity of the air in the West Indies is found to be expressed' by

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