forth discoveries and improvements, as the best evidence of their utility.

But astronomy has not only been enriched by the augmentation of its own immediate revenues; it has been also improved, during the period in question, by the collateral aid of other sciences and arts. The improvements in the mechanic arts, by furnishing the astronomer with more perfect instruments, have materially furthered him in his course. The discoveries in dynamics and optics, and the refinements which have taken place in mathematical science, though apparently of small moment when considered in themselves, yet, when applied to astronomical investigations, have proved highly important and useful. Formerly astronomy could only be improved through the medium of actual observation; but when the great Newtonian theory of the solar system was once established, a new path of inquiry, and new grounds of calculation, were laid down. Data, from that period, were afforded for ascertaining, with great precision, the orbits, the revolutions, and the inequalities of the several planetary bodies; and new light and aid poured in on every side, from the geometrician and the artist, as well as from the immediate inquirer in this sublime science.

Under this head it is proper to mention the introduction of the New or Gregorian Style of chronology into Great-Britain in 1752. In 1582 Pope GREGORY XIII. finding perplexity to arise in the computation of time, from some errors in the Julian Kalendar, which, antecedently to that period, had been used throughout Christendom, thought proper to order the formation and adop tion of a new style of reckoning. The astronomers and mathematicians whom he summoned to Rome for that purpose, after spending several years in investigating the subject, and adjusting the prin

ciples of another system, produced what has been since called the Gregorian Kalendar. In forming this method of computation eleven days were anticipated or lopped off from the old Kalendar, and a plan attempted for maintaining more chronological accuracy, by a proper distribution of Epacts through the year. The Gregorian Style, thus formed, was soon adopted by all the Catholic states, and in most of the Protestant countries, before the commencement of the eighteenth century. In Britain, however, and her dependencies, and in a few other Protestant states, the Julian or Old Style was not given up for a number of years afterwards. In 1752, by an act of the British Parliament, the Gregorian Kalendar was adopted, and, at the same time, the Ecclesiastical Year, which had before commenced on the 25th of March, was made to coincide with the Civil Year, and ordered, like that, to be computed from the first of January.

Besides the great names, and the important discoveries and improvements above detailed, it could be easy to add to the list many more abundantly worthy of notice. The numerous observations and writings of FERGUSON, LAX, VINCE, and others of Great-Britain; of BAILLY, DE ParCEVAL, BERNIER, SEJOUR, and DUVAUCEL, of France; of LAMBERT, GRISCHOW, OLBERS, DE WAHL, WURM, and KLUGEL, of Germany; of BIANCHINI, FRISI, MANFREDÍ, ZANOTTI, ODDI, CAGNOLI, and ORIANI, in Italy; of KLINGENSTIERNA, MALLET, PROSPERIN, and MELANDERHIELM, in Sweden; of ROMER, LOOWENOERN, BUGGE, and WURBIERG, in Denmark; and of many others, in almost every part of Europe, have all contributed something to the astronomical improvements of the age, and facilitated the acquisition of astronomical knowledge.

Nor has America been destitute of zealous students, and successful observers in astronomy. Besides the illustrious RITTENHOUSE, before mentioned, whose name alone would rescue his country from the charge of deficiency in astronomical genius, we can boast of COLDEN, WINTHROP, EWING, BOWDOIN, MADISON, PAGE, PATTERSON, ELLICOTT, WILLARD, and several others, who, if they have not made splendid discoveries, nor great additions to astronomical science, have yet published useful observations, and contributed to promote that degree of taste for this branch of philosophy which exists in our country.

From the foregoing review, it will appear, that almost every part of mechanical philosophy, during the eighteenth century, has undergone great and radical improvements; and that the path is evidently marked out to still greater and more interesting attainments. For much of this progress we are indebted to accident; but our obligations are also great to the genius and industry of individuals, and the labours and publications of many learned societies, who have with honourable zeal and perseverance encouraged experiments and enterprizes of discovery; and collected and made

i See Principles of Action in Matter, and the motion of the Planets explained from those Principles, &c. by CADWALLADER COLDEN, Esq. 4to. London, Dodsley, 1753. And also a subsequent publication by the same author, in the form of a Letter to the Earl of MACCLESFIELD, explaining the doctrines contained in the former work. Mr. COLDEN was for some years prior to the American Revolution Lieutenant-Governor of the province of New-York. Whatever may be thought of some of the opinions exhibited in these publications, they display genius, learning, and an unusual taste for mathematical and astronomical inquiries.

j The specimens which have been given to the public of the astronomical learning and skill of most of the gentlemen mentioned above, and of some other Americans, may be found in the volumes of Transactions which have been published by the American Philosophical Society, and in the Memoirs of the American Academy of Arts and Sciences.

known a multitude of important facts. It is also a remarkable characteristic of the age, that every branch of natural philosophy has been investigated in modern times, in a more practical manner than ever before, and more extensively and generally applied to purposes of economy and the arts. While the explorers of science have gratified liberal curiosity, and gained reputation for themselves, their inquiries have been rendered subservient to the abridgment of labour; the increase both of expedition and elegance of workmanship, in manufactures; and the promotion of human comfort, to a degree beyond all former precedent. In short, the number of heads and of hands at work, in the various departments of mechanical philosophy, at the close of the century under consideration, was unquestionably much greater than ever before since science was an object of human study. That much further, and more satisfactory light, therefore, may be expected to break in upon us, at no great distance of time, on many points at present involved in darkness, can hardly be doubted. "But the subject," says an eloquent writer, "is "still greater than our exertions, and must for ever "mock the efforts of the human race to exhaust "it. Well did Lord BACON compare natural phi"losophy to a pyramid; its basis is indeed the his

tory of nature, of which we know a little, and conjecture much; but its top is, without doubt, "hid high among the clouds. It is the work which "God worketh from the beginning to the end, in finite and inscrutable!"

Bishop WATSON's Chemical Essays, vol. i. p. 15.

CHAPTER II,

CHEMICAL PHILOSOPHY.

As Mechanical Philosophy has a respect to those motions of the larger bodies of the universe which fall under the inspection of our senses, so Chemical Philosophy is the science which explains those motions which take place among the minute component parts of bodies, and which are known chiefly by the effects which they produce; in other words, its object is, " to ascertain the ingredients "that enter into the composition of bodies-to ex"amine the nature of these ingredients, the manner “in which, and the laws by which, they combine, " and the properties resulting from their combina"tion." It may safely be asserted, that there is no branch of science in which the discoveries and improvements, during the last century, have been more numerous, or more important, than in this. Indeed, such has been their number, and their interesting nature, that to exhibit them in detail would be to fill many volumes.

Though some of the facts and principles which enter into all the systems of modern chemistry have been known for many centuries, and indeed as far back as history reaches; yet, as a regular science, it could scarcely be said to have had an existence prior to the middle of the seventeenth century. It was about that time that the learned societies in Europe began to be formed, and the reign of Alchemy to decline. In the inquiries then instituted in chemical philosophy, the celebrated Mr. BOYLE led the way. His speculations and experiments