Semi metals what. 2.53. bafter, Loadstone, Marble, Flint, Pebble; and -4°. Earths, which are either fatty, as the Boles, Clay, Fullers Earth, &c.-or Dryer, as Chalk and Oker. Semi-Metals are fuch Bodies as either con"tain the known and true Metals, or Bodies "fo like thereto, as that they may almost pass "for the fame." The Species hereof are either, 1°. fuch as confift of a true Metal, and a Salt; fuch as are Vitriols, both Green, Blue, White, Cyprian, &c. or, 2o. of Sulphur and a Metal, to which belong native Cinnabar, Antimony, Bifmuth and Zink. 3°. Among Semi-Metals are alfo ranked all cryftalline, ftony, and earthy Matters, which are Metals intermixed with them; fuch are moft native Ores, the Lapis Lazuli, Armenus, Hæmatites, Loadstone, &c. Principles This Hiftory of Foffils, is closed with an account of Foffils. of their Principles, which the Author reduces to Mercury, metallic Sulphurs, Salts, combuftible Sulphurs, Earth, Stones, and a volatile active Vegetables From Foffils, the Author proceeds to Vegewhat. 57. tables, which he defines to be humid Bodies, "containing different Juices, in various Veffels, "and adhering by fome external Part to another "Body, from whence they derive the matter of "their Growth and Nutriment." Hence he descends to a detail of the feveral Parts of Plants; as the Root, Leaves, Flowers, and Bark; gives their Structure and Office, the Juices contained in them, as Honey, Balm, Oil, Colophony, Gum and Rofin.-Befide thefe, which are common to all Plants, each has a peculiar Juice, which is formed by the joint force and refult of all the parts of the Body, fucceffively applied to the cruder Juice; and being thus prepared, contains the true charac characteristic Properties of that Plant, and the Virtues arifing from them. tables. The Chapter is clofed with an account of the Principles Principles of Plants, which he fhews to be the of VegeSpiritus rector, or prefiding Spirit; a fovereign Oil, the Seat of this Spirit, an acid Salt, a neutral Salt, an alcaline Salt, a faponaceous Juice, an Oil ftrongly adhering to the Earth; and laftly, Earth itself, the Bafis of all the reft. Animals he defines to be "humid Bodies, 63. "which live by a continual, determinate Mo- Animals. "tion of Juices in their Veffels; and contain-what. 66 ing vascular Parts, whereby, as with Roots, they imbibe the matter of their Growth and "Nutriment." The Veffels which do this office of Roots, are found in most kinds of Animals, feated in the cavity of their small Guts, and known by the Names of Lacteals and Mefenterics: the Meat and Drink brought to the abforbent Mouths of thefe Veffels afford the nutrimental Part, and fupply the office which the Earth does to Plants. The fimilitude and diverfity between Vegetables and Animals, is further illuftrated by the Author, both as to their Structure, Manner of Generation, Nutrition, &c.-In thefe, as in the other, the Food continually recedes the further from its former nature, and approaches nearer to the Properties of the Animal, the longer it is circulated thro' the parts of the Body. The Principles of Animals are, first, a fine fub- Principles til Spirit continually exhaling from them, wherein of Animals. their proper Character feems to be lodged, whereby they are distinguished from all others. -2°. Water, which affords the chief matter of most other Bodies, does the fame in respect of the Humours of Animals; which alfo, 3°. contain A a 4 a p. 70. mistry. a peculiar Salt never found fixed, nor yet fo volatile, as to exhale by the greateft Heat a healthy Animal is capable of neither is it acid, nor yet alcaline as it exifts in the Animal, tho' by Putrifaction and Fire, it may be rendered wholly alcaline. Of itself it approaches nearest the nature of Sal Armoniac; from which, however, it differs in certain Circumstances. The Author after a Multitude of Experiments, to determine the nature of this Salt, finds it to be mild and faponaceous; and concludes it formed of a concrete Oil, of a middle nature between the other Salts. 4. Oils, which are found of different kinds in the Body, fome mifcible with Water, and eafily volatile; others extremely mild, and scarce faline, &c.-Laftly, the Bafis of the Body is Earth, which appears the fame in Animals as in Vegetables. - Having dispatched the Object of Chemistry, Operations the Author proceeds to the Actions or Operations of Chethereof. The bufinefs of Chemistry is to change the feveral Bodies of the three Claffes above fpecified; which Change, he fhews, is produced in them by means of Motion. Now Motion may either be excited a-new, or fuppreffed when already raised or changed in its degree, by increafing or diminishing it; or the Quantity of it may remain the faine, and only its Course and Direction be changed: and all these again may either be in refpect of the whole Mafs, or of fome part thereof. From which few fimple conditions, all the different Effects of Chemistry, how numerous foever, do arife.-The Chemifts, it is true, would have us think there is more myftery in the matter; but this is only matter of craft. All their Calcinations, Fixations, Vitrifications, Sublimations, Fermentations, Putrifac tions tions, Digeftions, and other Operations are in effect reducible hereto. Nor does it appear, that the Art gives the true Principles Principles of things; or that we may judge of chemic. if genuine. the Compounds by the Simples into which they are chemically reducible: fince the Separation of Parts, thus effected, does not fhew that those Parts had pre-existed in the Body: the Operations whereby they become feparated from the reft, may make great Alterations in them, and even give them new Powers. In Nature, there appear to be Corpufcles unchangeable by any Caufe hitherto obferved, on account of their extream hardness. So that when the Analysis of a Body has reduced it into thefe, there is an end of all Divifion: thefe Parts are called Elements; and into thefe the Chemifts have often alledged, that Bodies are refolved by their Operations but it may be doubted whether fuch Bodies can by any Contrivance be procured and exhibited perfectly pure. The Author fuggefts many things to fhew they cannot in effect, the Limits of the Power of Chemistry, as affigned by Dr. Boerhaave, are, that from any determinate kind of Bodies, a certain determinate Operation will always produce certain determinate effects: but whether the matters thus produced actually exifted in the Body, before the Operation, is not eafy to fay. From the Action he proceeds to the Effects p. 79. produced by Chemistry, the principal whereof Effects of are reduced to four Claffes or Kinds, viz. Ex- Chemistry. traits, Clyffus's, Magifterys and Elixirs; the fpecific Characters of each whereof he lays down, indicating the feveral other more particular Effects and Operations reducible to each of them. Not that the terms above mentioned are used uniformly 79. uniformly among all Authors: fome take more Properties into their Ideas of them, other fewer ; the Author leaves every body to their choice, and only fays he has good Vouchers for that choice he has made. Hence he proceeds to the ufes of Chemistry; Ufes of which he illuftrates in feveral Sciences and Arts, Chemistry in Phyfics, beginning with Natural Philofophy; where Fire, which is the great Inftrument of Chemistry, is alfo the ufual means which Nature makes use of in producing moft Phyfical Phænomena. In Medicine. Arts. The Ufe of Chemistry in the Art of Phyfic is obvious; as it explains the nature both of the folid and fluid Parts of the Body.-The Author pursues this use thro' all the Parts of Phyfick, as Pathology, Semeiotice, Dietetice, and Therapeutice; In the Me-and proceeds hence to the mechanical Arts, where chanical he fhews Chemistry of ufe in Painting, by the Colours which it furnishes; in Enamelling, which is founded wholly on Chemistry; in the Art of Glafs, which is alfo a chemical Procefs; in the Art of Dying, which depends wholly on it, both as to the preparing of the Stuffs for imbibing and retaining the Colours, and the ordering of the Colours themselves; in Painting on Glafs, which is wholly performed by chemical Means; in the Art of making Gems to vye with natural ones, which is performed either by giving the proper Colours to Glafs, or by ftaining Cryftal; in the Art of Metals, or the working and fitting them for human Ufe, which is a chief Branch of Chemistry. Chemistry is alfo of use in the Art of War, as managed among the Moderns, which depends on Gunpowder a chemical Compofition; in Natural Magic, where ral Magic. the usefulness of Chemistry is fcrupulously purfued by the Author into a long detail of par In natu ticulars, |