Containing an Introduction relative to the Construction and Uses of several LONDON: PUBLISHED BY W. PHILLIPS, GEORGE YARD, LOMBARD STREET: SOLD ALSO BY 15012. e. 12. INTRODUCTION. General Observations. METEOROLOGY, though greatly advanced of late years, especially in what regards the perfection of its instruments, and the art of observing the changes of the atmosphere, is yet far from having acquired the regular and consistent form of a science. Its facts lie for the most part scattered, or rather buried, in volumes chiefly taken up with other more cultivated branches of natural philosophy: and it is only where detached publications have been ventured on, by individuals engaged in the study of particular classes of phenomena, that its principles have been developed with the clearness and method of which they are susceptible. A pretty large number of observers have been long engaged in doing for this science the office which the Chaldean shepherds are thought to have performed for astronomy. We may now probably venture, with safety, to anticipate some of those conclusions which posterity will otherwise have to draw from our data—to lay the ground-work of the edifice, if not to proceed to build, with the present materials. Should it be inquired, for what end-the answer (without travelling to more remote consequences) may be-For the benefit of agriculture and navigation: two objects of that magnitude that the most distant prospect of the smallest permanent addition to our store of knowledge and experience concerning them, will be slighted by none but those, who have not duly considered the influence of science on the arts, and of these on the well-being of society. An extensive co-operation of observers in different countries has been justly deemed essential to the perfection of meteorological research.* But if we except the single instance of the Society of Manheim, patronized by the Elector Palatine, the voluminous Transactions of which, compiled from an extensive correspondence, include the years from 1781 to 1785, there seems to have been nothing done on a great scale to attain this object. In the mean time observations continue to be made and published throughout Europe: and it is probable that many individuals have acquired, at least, a knowledge of the peculiar features of their own climate, and of the facts which, properly arranged, would form its history. The production of such a work for each of those districts, in which the requisite observations have been made, would greatly abridge the labour, if it did not remove the principal difficulty, of a general view of the phenomena of our atmosphere, in their various localities and relations through the year: which being obtained, we might proceed to constitute, on sound principles, the theory of the science.† The volume, which on such considerations is now offered to the public, is composed chiefly of the observations of ten years, from 1807 to 1816 inchusive, made in the neighbourhood of London. They have appeared, for the * Kirwan on the Variations of the Atmosphere, Dublin, 1801. In the spring of last year, I attempted to give a coup d'œil of the facts and principles of this interesting department of knowledge, in the way of lectures to a circle of friends. The best sketch which I was able to get ready for the occasion, aided by the globe, some graphic representations, and a few experiments with instruments, proved so far satisfactory, that I have been induced to give expectations of enlarging and publishing it. But I cannot promise, as my friend William Phillips (whose “ Lectures on Astronomy " instructed and gratified the same audience) has ventured to do for me, that this shall be done "at no distant period." most part, as monthly reports in different scientific Journals; but of necessity in an insulated form, and without the connexion and the illustrations which it has now been my endeavour to bestow upon them. They are intended to form (in a Second Volume) the basis of such a methodical account as I have hinted at, of the climate of London: or rather of that district in which the Metropolis with its suburban branches, have during the last ten years, been rapidly extending. Of the Calendar and Arrangement. In introducing to the reader's notice this collection of observations, I ought in the first place to account for the peculiarities of the arrangement. I had given them, from the first, to the press, not as usual in calendar months, but in periods of a lunar revolution. In so doing I had two objects in view. In the first place I obtained an earlier insertion in the periodical publications (which come out on the first of each month) than would have been possible, had I carried them up to the close of the preceding month: the difference, as the reader will perceive, is on an average two weeks in my favour, though at the expense to the publisher of inserting one table more in the course of two years. Secondly, and what more induced me, my attention had been for some years called to the question, so much agitated among meteorologists, whether, and in what way, the relative positions of the moon in the dif ferent parts of her complex orbit, influence the state of our atmosphere. I thought the most convenient way of investigating this subject, and which might bring out, even unexpectedly, facts capable of deciding the question, would be to digest my results in lunar periods at once. I lost by this means the facility of having them compared 8 |