motions of the body, and therefore continuance in an open vessel, conduces more to separation; but in a vessel perfectly closed, to commixture, or combination, and in a vessel imperfectly closed, without excluding the air, to putrefaction*; and in all these cases, instances of the works and effects of continuance are to be diligently collected from all quarters.

The fifth means of operating, viz. by govern ment and regulation of motion, is extremely powerful. We call that the government and regulation of motion, when one body, by meeting another, hinders, repels, or directs its spontaneous motion. And this generally consists in the figure and position, or situation of the vessels; thus the figure of an erect cone forwards the condensation of vapours, in alembics, but an inverted cone promotes the purging of sugar, or the discharge of the treacle into the receivers†. Sometimes also curvature, or flexure, straitness, and dilatation, are required by turns, and the like. And all percolation depends upon this, that whilst the opposing body opens to one part of the liquor, it closes upon or stops another‡.

* See the article Putrefaction, in the Sylva Sylvarum. † And hence the figures, or make of all the chemical, or other vessels, may be easily determined. See Boerhaave's Chemistry, under the chapter of Vessels.

See the articles Clarification and Percolation, in the Sylva Sylvarum.

Nor is the business of percolation, or other regulation of motion, always carried on by exter-> nal means, but also by internal, or by means of one body within another, as when stones are put into water to collect its sediment, or earthy parts, or when syrups are clarified with the white of eggs, whereto the grosser fæculences adhere, and may be afterwards separated. And to this regu lation and direction of motion, Telesius, from a slight and superficial consideration, attributes> the figures of animals, as if they were moulded," and took the impression of the veiny, wrinkled, and hollowed sides of the matrix. For he ought to have considered, that though eggs also are formed in the uterus, after the same manner as the fœtus, yet no wrinkles or inequalities appear on their shells. But it is true, indeed, that the regulation of motion produces figure in moulding and cast-work.

The sixth means of practice consists in operating by consents, or avoidances, which frequently lie deep concealed; for those usually called occult, and specific properties, and sympathies and antipathies, are in great measure the corruptions of philosophy. Nor can we have any solid hopes of discovering the consents of things, before the discovery of forms, and simple textures, for consent is no more than the sympathy or correspondence of forms and textures to each other.

But the greater and more universal consents of things, are not absolutely obscure. We will therefore begin with these. The first and prin cipal diversity of things is this, that some bodies differ greatly in their quantity, and rarity of matter, yet agree in texture, whilst others agree in quantity, and rarity of matter, but differ in texture. For it is well observed, that the two chemical principles, sulphur and mercury, run, as it were, through the universe of things And, doubtless, there appears to be a certain consent of nature, or an agreement of bodies, in these two principles, from a consideration of the most universal phænomena. Thus there is an agreement betwixt brimstone, oil, unctuous exhalations, flame, and perhaps the body of the stars; and again, between quicksilver, water, and aqueous vapours, air, and perhaps the pure interstellar æther. But these two larger sets, or tribes of things, differ prodigiously from each other in quantity of matter and density, though they greatly agree in texture, as appears in numerous instances. But, on the other hand, the different metals have a great agreement in quantity of matter and density, especially in respect of vegetables, &c. but differ greatly in texture,

* Sec the Sylva Sylvarum, under the article Principles of Chemistry.

whilst vegetables and animals have an infinite variety of texture, yet differ not considerably in quantity of matter or density *

The next most general consent is that betwixt primary or perfect bodies, and their fostering matters, that is their solvents and aliments. It must therefore be examined, in what climate, in what earth, or glebe, and at what depth, all the metals are generated † ; and so of gems, whether those of the rock, or produced in mines; in what glebe, or earth, all trees, shrubs, and plants, principally grow and delight; likewise what amendments, or kinds of composts, whether of chalk, sea-sand, ashes, &c. succeed the best; and which of them are fittest, and most serviceable, according to the difference of the land. So again, the grafting and inoculating of trees and plants, with the methods thereof, for the most successful ingrafting has a great dependance upon consent, betwixt the trees ingrafted. In which respect, it is an agreeable experiment, which we are informed was lately tried, of the ingrafting of field trees, which has hitherto been practised only in those of the garden; whence the leaves and mast of the former have been ob

* See the History of Condensation and Rarifaction. + See Becher's Physica Subterranea.

‡ See Mr. Boyle's piece of the Origin and Virtues of gems.

tained much larger, and the trees rendered more shady*. In like manner, the aliments of animals must be respectively noted in general, together with their negatives +; for carnivorous animals cannot be fed with herbage. Whence, (though the will in men has a greater influence over their bodies, than in other animals) the order of the folietani, or leaf-eaters, is said to have dropped, after trial, upon finding that leaves were not capable of nourishing the human body‡. Again the different matters of putrefactions, whence little living creatures are bred, should be likewise regarded §.

The consents betwixt perfect bodies, and their subordinates, as exemplified above, are sufficiently manifest, whereto may be added the consents betwixt the senses and their objects. And as these latter consents are exceeding evident, well observed, and thoroughly discussed, they may afford great light to other consents that are hitherto latent ||.

* See the Sylva Sylvarum, under the article Vegetables and Vegetation.

+ As in discovering the form of heat. See the Tables, Aph. 12, &c.

See the Sylva Sylvarum.

§ Ibid.

See the Sylva Sylvarum, under the articles Imagination, Senses, Sound, Sympathy, &c.