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Jupiter and Saturn, the mountains and cavities in the moon, and the changes which take place in the fun's difc, are thus difcovered, and afford matter for admiration and inquiry.

Neither is this delightful science of optics confined to the contemplation of diftant objects. Minute animals, the veffels of plants, and, in fhort, a new world in miniature, is difclofed to our view by the microscope, and an inexhaustible fund of rational entertainment and knowledge is brought within the sphere of our senses.

Every one is acquainted with the benefits derived from the science of Hydroftatics, to which we are indebted for many ufeful inventions. Among thefe are wind and water mills, pumps, fire engines, fteam engines, &c. &c.

Chemistry is productive of great and fingular advantages to fociety. Metallurgy in its utmoft extent, the arts of making glass and pottery, of dying, and many others, together with a very confiderable part of the Materia Medica, are dependant on this branch of Philofophy. The vaft importance of Metallurgy may be rendered obvious from the fingle confideration of the many ufes to which iron is applied. Without this metal we should be almost totally incapable of making any utenfil or inftrument. It is difficult to recollect any production of art in the formation of which iron is not made ufe of; and the very exiftence of naval commerce depends on its magnetical property.

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Philofophy

Philosophy is not therefore a dry study, but a pursuit of the higheft utility and entertainment. Those who cultivate the sciences know that they naturally produce a fincere and difinterefted love of truth. An enlarged view of things destroys the effects of prejudice, inspires the properest ideas of the great original caufe, and promotes a deteftation of every thing that is mean or bafe. And if there be a pleasure in attending to objects which fill the mind by their immensity, and delight the imagination by the continual discovery of new and fublime analogies, it is not to be wondered that Philofophers purfue their ftudies with a degree of attention and ardor, which is not found in any other set of men.

The order of arrangement in the prefent work, is fuch as was fuggefted by the subjects themselves. After a curfory enumeration of the general properties of matter, motion is principally attended to, being that affection of matter by which all changes are brought about. Mechanics and astronomy naturally follow, and are fucceeded by an elucidation of the properties and motion of light. The more complex motions of fluids, and the atmospheric phenomena are next confidered. Thus far it will be observed, that the work treats of fuch general effects as arife from the motions of bodies, without any particular respect to those specific properties which distinguish them into various claffes. The remaining part of the treatife is employed upon these specific properties: a long fection upon chemistry is given for the purpose

purpose of explaining them as far as they are at present known, and are capable of being understood by mere reading. Magnetifm and electricity occupy the concluding fections. Upon the whole, therefore, it will be seen that the most scientific and best established parts of Natural Philosophy are first treated of, and are followed in fucceffion by others which are lefs understood.

This treatise being intended to give a clear account of the prefent ftate of Natural Philofophy, to fuch as poffefs very little mathematical knowledge; care has been taken to select such facts and experiments as tend to establish elementary truths. The varieties of experiments of the fame kind are not therefore numerous; but it is hoped that the advantage of a greater number of general principles, is by that means obtained. Philofophical Instruments likewise, are not minutely described. References to the parts of drawings are not often read or underftood: for which reafon it was thought better to explain their general conftruction, and leave the minutiæ to ocular inspection. The grand object throughout has been to relieve the memory, and affist the understanding, by concifeness and illuftrative arrangement.

Those prolix difquifitions, which render the commentator less intelligible than the author commented upon, are thus avoided; neither has the affectation of familiarity, which is ufually attended with a lax,

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and unphilofophical explanation of one event by another equally obfcure, been indulged. On the contrary, the author has every where endeavoured to preferve that folidity of argument, and precision of expreffion, which diftinguish the works of the best Philofophers. And, notwithstanding the nature of the undertaking unavoidably required a deviation from those elegant and general principles which are obtained by strict mathematical reafoning; yet it is prefumed that the ftudent will find nothing in this treatife, which he will be under the neceffity of unlearning, when he attempts the perufal of thofe books to which this is offered as an introduction.

The attentive examination of other books, to which the writer of this performance has had recourse, has fhewn him, that even the works of thofe great men, who deferve and poffefs the highest reputation, are not free from errors of importance. The present occafion does not require the difagreeable task of pointing them out; but this very confideration will not permit him to hope that his diligence has entirely excluded miftakes. However he has little to fear on that account, being fenfible that those who are the best able to discover them, will at the fame time be the readieft to exercife that candor which every writer has need of

The liberty which has been taken in altering the words of other authors, and adapting them to the purpose of this work, would have prevented the use

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of formal quotations if they had been supposed neceffary; and as the present intention is not at all hiftorical, the names of authors have been avoided as much as was confiftent with the with of the writer, to evade the fufpicion of plagiarism. If plagiarism can be imputed to the author of an epitome of science, this acknowledgement must be allowed to obviate the charge.

In the printing, every thing which could be imagined of service to the book, as a manual of philosophy, has been done. A varying title at the head of each page, and copious indexes, are annexed. From thefe the reader will fee that scarcely any fact of importance has been omitted.

The learner who may be induced to fix his chemical reading in his memory by recurring to experiment, which may be done with very little expence, is cautioned to beware of the danger with which it is fometimes attended. The folution, evaporation, and calcination of uninflammable matters, may be performed in the common apartments of a dwelling-houfe; but the diftillation of corrofive or inflammable substances ought not to be attempted but in a place prepared for the purpose. The bursting of a retort containing any concentrated fuming acid, must be very deftructive to furniture, as well as prejudicial to health; and ardent fpirits, refins, and the like, would endanger the house if a fimilar accident were to happen. It is impoffible to give

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advice

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