THey that have any true knowledg of this Noble Art , are without doubt fully perswaded of the usefulness of it ; for it is the key which alone can unlock to all Naturalists the door of Nature's secrets ; by reducing things to their first principles ; by giving of them new forms ; and by imitating Nature in all its productions and Physical alterations . Without it Physitians would be at a stand how to penetrate into the many Fermentations , Effervescencies , Distillations , and other Operations , which are performed in the body of man , and are the immediate cause of many grievous Distempers ; to which Art the same Physitians must be beholding for the Remedy as well as the Knowledg of the Disease ; for we must own that Chymistry does furnish us with the more effectual Medicines for the more inveterate and obstinate Affections , and often supply the failings and deficiencies of those of the vulgar Pharmacy . Chirurgeons likewise cannot be without Chymistry , nor can with good success undertake the Cure of all Diseases pertaining to their Art without Chymical Remedies , and knowledg of their Operations : And it is impossible that Apothecaries should make their compositions like true Artists , if they know not how to preserve the principal vertue of their Ingredients , and separate the pure from the impure , and heterogeneous in natural commixtures , as unprofitable to their intention , which is not learned without the aid of this noble and excellent Art. Finally , most of the ingenious mechanick Arts are beholding to this : Painters have from it their most lively and glorious Colours : Engravers cannot work without the assistance of those corrosive Spirits prepared by Chymistry : Diers cannot exalt their Colours without the instruction of Chymists : One might alledg an infinity of other such Examples , which might prove the necessity of this Art ; but we omit them for brevity sake .

TO begin with Mercury , or the Spirit , which , as the most excellent of the three , does in the resolving of bodies , first present it self to our senses ; we shall say that it is a subtil , light , and penetrating substance , which gives life and motion to bodies , makes them grow and vegetate ; and because it is a continual action and motion , it would not long stay in any body , if it were not retained by the other Principles more fix and stable than it self : And from hence it follows , that those Mixts in which this substance predominates , are not very durable ; as we may observe in Animals and Vegetables , which perish much sooner than Minerals and Metals , which are almost destitute of this Principle .

Sulphur is the second Active Principle , but much inferior to the Spirit ; its substance is oleaginous , subtil , penetrating , and inflamable ; it is easily reduced into a pure Principle as well as the others . When it contains some spirituous and aery Particles , it swims upon the water , as the Aromatick subtil Oils of Rosemary , Sage , Turpentine , and others ; and if it contain some part of Salt and Earth , then it is a thick and heavy Oil , which sometimes swims in the middle of the Flegm , sometimes goes to the bottom ; as we observe in the Oils of Gums , Bitumens , and Gross Woods , &c. which are distilled with violent fire : 't is this Principle which is said to cause Beauty or Deformity in Animals , of the different smells and colours in Vegetables , and of the ductibility and malleability of Metals . It binds together all the other Principles , which without him would fall a-sunder , by reason of their little correspondence and contrarieties ; it preserves bodies from corruption , sweetens the acrimony of Salts and Spirits ; and being of a fiery nature , it preserves those Vegetables where it abounds , from the rigour of cold and frosts , and other injuries of the weather ; as we may observe in Cyprus and Fir-trees , and others that are green all Winter .

The third Active Principle is Salt , which appears to us after that the volatile parts are evaporated and exhal'd , because it remaineth its self fix'd with the earth , from which it is separated by dissolution and evaporation ; then it offers its self to our view in the form of a brittle substance easily pulveriz'd ; and that demonstrates its driness , which appears likewise by its desire of moisture , which it attracts from the Air so powerfully , that in a small time it becomes fluid . The way of purifying the Salt is by fire , and it is incombustible : it s office in the Mixt is to retain the Spirit , and preserve the Sulphur from combustion , and is as it were their common Basis or Foundation ; it is the cause of the different tasts of things , and renders those bodies where it abounds , so durable , that they are almost incorruptible : As for Example ; the Oke , which has in it much Salt , and little Oil , is of a lasting subsistence , and so are many other Mixts of the same nature .

The Earth is the last of all our Principles ; and though it be esteemed of little benefit in natural mixture , it is not unnecessary , since it retains the Salt , and the other Active Principles , which would else be easily dissolved , and carried away by the water . When it is entirely destitute of all the other Principles , it is called Terra damnata , or damned Earth : The use of it in Chymistry , is , only to hinder the Salts from being too easily melted down ; and so we forbear to treat any further of it .

To Congele , is to suffer those Bodies to grow hard by cold , which fire before had melted and liquefied : This Operation is practised upon Metals , Minerals and Salts , which are purified by the violence of a melting fire , and when they are exposed to the air , grow hard . The same is observed in the fat of Animals , and in the gums , rozins , and balms of Vegetab es , which being melted by the fire , and their grosser parts thereby separated , are again congealed , by being exposed to the cold air .

To Corporize is to incorporate Spirits , which is often practised in Acids , which are mingled with fix'd Salts , or with dry Earths : As for example , when one puts the Spirit of Nitre or of Aqua-fortis with the fix'd Salt of Tartar , the last retains the first so strongly , that of them both one may make a good sort of Saltpeter ; and likewise when one puts very strong Vinegar , or some other acid Spirit upon Coral or Pearls , they presently retain all the acidity which the liquor contained , and it is fix'd with them .

To Crystallize , is to reduce into Crystals , Nitre , Salts , Vitriols , and others , which were first dissolved , filtred , depurated , and evaporated , till a skin appeared upon the liquor ; then they are exposed to the cold air , where the Salts congeal by little and little , and by retaining some part of the water with which they had been dissolved , they appear diaphanous , and crystalline ; which transparency they lose upon the least heat of the Sun , who depriving them of their water , makes them opake again .

Detounation , or Fulminating , is the driving out of a Mineral its impure and volatile Sulphur , and preserving its intern and fix'd Sulphur : this Operation is performed by the means of Saltpeter , in preparing Antimony and other such bodies .

To Digest , is to concoct things by a moderate heat ; like that of our stomachs , which concocts raw things , ripens and sweetens sour and austere ones , separates the pure parts from the impure , and extracts the best and most juicy parts of each substance . This Chymical Digestion is ordinarily perform'd by some liquor or menstruum fit for the matter digestible ; it differs from maceration only , because there is requir'd heat in one , which is not in the other .

To Dissolve , is to reduce hard and compact bodies , by means of some dissolvents , into a liquid form , as we see in the dissolving of Gold by Aqua-regis , and of Silver and others by Aqua-fortis .

To Edulcorate or Sweeten , is to take away by often lotions , and reiterated effusions of some liquor , the impression made by Salts and Spirits in Chymical Preparations , as in Precipitated Magisteries and others .

To Extinguish , or Quench , is to dip or steep a substance made red-hot by fire , in some water ; it is particularly practicable in Metals and Minerals ; either to make them brittle , as in the extinction of pibbles in water , or to imprint into them some vertue of those liquors in which they are extinguished , as in the extinction of Tutie in Rose or Fennel-water ; or sometimes to communicate vertue to the water , as in the extinction of Steel .

To Evaporate and to Exhale differ from one another in this , that dry bodies are exhal'd , and moist ones evaporated ; as for example , when we Amalgam any Metallick body , we exhale the Mercury by fire , and the Metal remains calcin'd in the bottom of the Crucible . But Evaporations are done , as when for example , we drive away the superfluous humidity of Salts and Extracts ; purified by their dissolutions and filtrations , to reduce them into a consistence necessary for their preservation .

To Extract , is to separate in Animals and Vegetables the purest parts from the most gross , by fit menstruums that are proper for the extracting of those substances which the Artist desires : as for example , we extract the rozinous substance of Jalap by Spirit of Wine , because that the rozin is the sulphureous part of the Jalap ; and that Spirit of Wine does likewise contain a subtil Sulphur , which easily unites with the other . So in all Extractions the Artist must have a regard to find out a menstruum fitted to the substances he desires to extract .

To Ferment , is to reduce the volatile and spirituous parts of Mixts from rest into motion ; or , as the Philosophers say , a potentia in actum , from power to act , by disengaging them from the clog of the more gross and terrestrial parts , as is seen in all fermented liquors , and particularly in Wine , which having been fermented , easily yields its spirit inflamable by the least heat of fire ; whereas the Must quite contrary retains all the spirituous and subtil sulphureous parts ; and being reduced into the consistence of Honey , which they call Sape , Rob , or Q●iddany , without loss of any substance , save insipid water , or flegm ; it s active and volatile parts are so well fastned and retained by the fix'd Salts , that they seldom fly away but by the violence of fire , or the action of fermentation : it has much of the nature of digestion , except that digestion , I mean Chymical , is made by an external heat , and fermentation is by its own power and an effect of the intrinsick fire of Mixts .

To Filtrate , is to let any thing strain through another body ; it is performed most conveniently thorow grey Cap-paper into a glass-tunnel .

To Fix , is to stay and retain some body which of its self is volatile , so as to make it resist the fire : this Operation is performed by the means of fix'd bodies . The experience may be made in Sal-armoniack , which , though extremely volatile , yet being mingled with quick-lime , is so fix'd , that the greatest part of it endures the violence of the fire , which alone it would not have done .