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• The Work before us supplies accurate, though popular, instruction on a variety of topics. It is written in a correct and tasteful style, enlivened by many exquisite quotations from the poets of the day; and is interspersed with such reflections as flow natsrally from the conviction that knowledge, to be extensively beneficial, either to its possessor or to others, must be purified by religion, manifested in benevolence, and consecrated to God.'- Eclectic Review for February 1815.

• The History of Astronomy, and the first principles of the art, are well displayed in this entertaining volume. It will be the source of much amusement and information upon the mysteries of the Almanack, and the appearances of the heavenly bodies. Much curious matter respecting the several Saints' Days has been collected together; which, with an accurate account of the flowers which blossom and the buds which appear in the course of every month, cannot fail to interest and instruct the reader.:British Critic for December 1814.

• We have no hesitation in giving “ Time's Telescope" our unqualified commendation.'-Gentleman's Magazine for Febru

ary 1815.

· This is the second annual appearance of “ Time's Telc. scope," and we willingly confess that it is niuch improved. The quantity of useful and interesting matter which is here amassed together, distributed with judicious appropriation 'under each month, is highly creditable to the industry and taste of the compiler.'- Nero Universal Mugazine for December 1814.

This volume contains a good deal of information, useful and p.easant. Opportunity is taken to introduce articles of various descriptions which comprise useful matter, to be met with in no concise form, but in a variety of works only, on the shelves of a well-furnished library. As all have not that accommodation, this moderate-sized volume may, in a considerable degree, servé as a substitute.'— Literary Panorama for December 1814.

Notices of Time's Telescope for 1816. 'Time's Telescope is compiled with skill and judgment, and contains much desirable miscellaneous information, and many interesting and instructive sketches, particularly on some parts of Natural History. We recommend this Work to the attention of our juvenile readers, who will find it an agreeable and instructive companion.'-Monthly Review for November 1816.

. We are glad to see that the Editors of this useful work find encouragement to continue it annually, and that the articles it contains increase in their interest.'--Gentleman's Magazine for August 1816.

Notices of Time's Telescope for 1817. We have already noticed the preceding volume of this amusing and instructive performance; and we have now little to add to or deduct from the encomiums whico we deemed it our duty to pass on the contents of that part; the plan being still the same, and the execution and arrangement as nearly as possible on the same model. We shall not consider it as requisite for us to continue our report of this annual publication.'—Monthly Review for August 1817.

"The Almanack, in order to be reduced to a cheap and convenient form, has become so enigmatical, that a more enlarged explanation of its contents and references is very desirable; and such is the purpose of the “ Time's Telescope, which appears to us to be executed in a very amusing way, and the Astronomical portion of it is prepared evidently by a person of science.'Critical Review for December 1816.

A very entertaining and useful compendium of multifarious lore.'-- Eclectic Review for January 1817.

• The industry of the compiler has been successfully exerted in the collection of an entertaining, and, in many respects, useful mass of materials.' - Antijacobin Review for December 1816.

(There is in this volume an excellent Introduction to the " Principles of Zoology," quite studded with poetical citations; and a copious index is added to the whole series. In point of quantity and quality, indeed, the present is fully equal, if not superior, to any of the preceding volumes; and our readers will not readily find a more attractive “ New Year's Present" for their juvenile friends, which, while it acquaints them with the please ing wonders of Nature, teaches them, at the same time, that all these “ are but the varied God.”—Gentleman's Magazine for December 1816.

Notices of Time's Telescope for 1818. We cordially recommend this volume to the attention of persons of every age and taste, but particularly to the enquiring youth of both sexes.'- Antijacobin Review for December 1817.

• Time's Telescope for 1818 deserves the same praise, and is entitled to the same support and encouragement, which the former volumes have received from the public.'- British Critic for December 1817.

• The present volume is quite equal in entertainment and instruction to any that have preceded it.'-Gentleman's Magazine for November 1817.

Introduction.

A COMPENDIUM of CHEMISTRY. SURROUNDED by an infinity of substances differing in their natural forms, and endued with essentially different properties, the contemplative mind cannot but seek for the gratification of learning the respective combinations of matter on which these innumerable varieties depend. To assist in this most pleasing and interesting enquiry, we offer to our readers a comprehensive sketch of the several facts and observations which are at present known and admitted. In presenting this, we trust, acceptable, offering to our readers, it is gratifying to remark, that we shall place before them a brief but compendious system of CHEMISTRY, which teaches the constituent principles of bodies, the results of their various combinations, and the laws by which those combinations are effected.

The common atmospheric air which we breathe, and the simple water wbich we drink, heretofore considered as elementary substances, are now known to be compound substances, into the composition of which different aërial or gaseous matters enter.

CALORIC, or the matter of heat, may be considered as a substance of very considerable chemical influence. It appears to be highly elastic, subtle, and impon

derable. It unites chemically with all bodies, in a quantity proportioned to their affinity with it. From its elasticity it seems to oppose the attraction of cohesion, and to separate the particles of matter. By the prevalence of its influence solid bodies become fluid, and these assume a gaseous form. It is constantly tending, by its diffusion, to form an equilibrium of temperature.' Bodies through which it is thus transmitted are termed conductors of caloric.

Different bodies require different quantities of caloric to render them of a similar temperature. This property is termed the capacity for heat, and the quantity thus required is called specific heat. Whilst thus in union, and not manifesting itself, it is termed combined caloric, or, according to Dr. Black, latent heat; but when perceptible it is termed free caloric, or sensible heat.

Light is an elastic fluid, being reflected from bodies which it cannot penetrate. Passing near to any substance, it is more or less attracted, and suffers a proportionate degree of inflection. In passing through media of different densities it suffers different degrees of refraction. This is always found to be greatest in combustible bodies; and hence Sir Isaac Newton suspected the diamond to be a combustible body.

Its influence on the vegetable kingdom is very obvious; indeed, its chemical affinities are so numerous and powerful, that few substances are free from its influence.

ATMOSPHERIC AIR is formed by the union of oxygen and nitrogen, always in the proportion of 73 of the former to 27 parts of the latter.

1. OXYGEN GAS is colourless and elastic, but becomes fixed in numerous bodies, from which it may be extricated by the application of such substances as have a superior degree of affinity with the bases with which it was united. Thus it may be obtained from black manganese, as it is called, by adding to it the acid of sulphur, and by applying heat to the mixture.

Oxygen combines with other bodies in different quantities and modes, and bence result different states of those bodies. When in the smaller quantities an oxide is formed, possessing no acid properties; and in the larger, acids are produced. From the combination of acids with metals, earths, &c. salts are formed, and which by the termination ate are designated as holding their full dose of oxygen; and by the termination ite, are marked as holding a minor dose.

Various oxides may be also formed with different doses of oxygen, and these are marked by prefixing the Greek numeral to the term oxide, the higher the number the higher the degree of oxidation being implied, Thus protoxide is the first oxide, with a minimum of oxygen. Then follows deutoxide, tritoxide, &c. to peroxide, or last oxide, holding the maximum of oxygen.

Oxygen is that part of the common air which is

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