« PreviousContinue »
rishment is turned into flesh; that is it which we call assimilation. The other is, when the conversion is into a body merely new, and which was not before; as if silver should be turned to gold, or iron to copper: and this conversion is better called, for distinction sake, transmutation. Experiment solitary touching alterations, which
may be called majors, 839. THERE are also divers other great alterations of matter and bodies, besides those that tend to concoction and maturation, for whatsoever doth so alter a body, as it returneth not again to that it was, may be called alteratio major; as when meat is boiled, or roasted, or fried, etc. or when bread and meat are baked; or when cheese is made of curds, or butter of cream, or coals of wood, or bricks of earth; and a number of others. But to apply notions philosophical to plebeian terms; or to say, where the notions cannot fitly be reconciled, that there wanteth a term or nomenclature for it, as the ancients used, they be but shifts of ignorance; for knowledge will be ever a wandering and indigested thing, if it be but a commixture of a few notions that are at hand and occur, and not excited from sufficient number of instances, and those well collated.
THE consistences of bodies are very diverse: dense, rare ; tangible, pneumatical; volatile, fixed; determinate, not determinate; hard, soft; cleaving, not cleaving; 'congelable, not congelable; liquefiable not liquefiable; fragile, tough; flexible, inflexible ; tractile, or to be drawn forth in length, intractile ; porous, solid; equal and smooth, unequal; venous and fibrous, and with grains, entire; and divers others; all which to refer to heat, and cold, and moisture, and drought, is a compendious and inutile speculation. But of these see principally our Abecedarium naturæ ; and otherwise sparsim in this our Sylva Sylvarum: nevertheless, in some good part, we shall handle divers of them now presently.
Experiment solitary touching bodies liquefiable, and
not liquefiable. 840. LIQUEFIABLE, and not liquefiable, proceed from these causes : liquefaction is ever caused by the detention of the spirits, which play within the body and open it. Therefore such bodies as are more turgid of spirit; or that have their spirits more straitly imprisoned; or, again, that hold them better pleased and content, are liquefiable: for these three dispositions of bodies do arrest the emission of the spirits. An example of the first two properties is in metals; and of the last in grease, pitch, sulphur, butter, wax, etc. The disposition not to liquefy proceedeth from the easy emission of the spirits, whereby the grosser parts contract; and therefore bodies jejune of spirits, or which part with their spirits more willingly, are not liquefiable; as wood, clay, free-stone, etc. But yet even many of those bodies that will not melt, or will hardly melt, will notwithstanding soften; as iron in the forge; and a stick bathed in hot ashes, which thereby becometh more flexible. Moreover there are some bodies which do liquefy or dissolve by fire: as metals, wax, etc. and other bodies which dissolve in water; as salt, sugar, etc. The cause of the former proceedeth from the dilatation of the spirits by heat: the cause of the latter proceedeth from the opening of the tangible parts, which desire to receive the liquor. Again, there are some bodies that dissolve with both; as gum, etc.
And those be such bodies, as on the one side have good store of spirit; and on the other side, have the tangible parts indigent of moisture; for the former helpeth to the dilating of the spirits by the fire; and the latter stimulateth the parts to receive the iquor. Experiment solitary touching bodies fragile and
tough. 841. Of bodies, some are fragile ; and some are tough, and not fragile; and in the breaking, some fragile bodies break but where the force is; some shatter and fly in many places. Of fragility, the cause is an impotency to be extended; and therefore stone
is more fragile than metal; and so fictile earth is more fragile than crude earth; and dry wood than green. And the cause of this unaptness to extension, is the small quantity of spirits, for it is the spirit that furthereth the extension or dilatation of bodies, and it is ever concomitant with porosity, and with dryness in the tangible parts : contrariwise, tough bodies have more spirit, and fewer pores, and moister tangible parts : therefore we see that parchment or leather will stretch, paper will not ;, woollen cloth will tenter, linen scarcely. Experiment solitary touching the two kinds of
pneumaticals in bodies. 842. ALL solid bodies consist of parts of two several natures, pneumatical and tangible; and it is well to be noted, that the pneumatical substance is in some bodies the native spirit of the body, and in some other, plain air that is gotten in; as in bodies desiccate by heat or age: for in them, when the native spirit goeth forth, and the moisture with it, the air with time getteth into the pores. And those bodies are ever the more fragile ; for the native spirit is more yielding and extensive, especially to follow the parts, than air. The native spirits also admit great diversity; as hot, cold, active, dull, etc. whence proceed most of the virtues and qualities, as we call them, of bodies : but the air intermixed is without virtues, and maketh things insipid, and without any exstimulation. Experiment solitary touching concretion and disso.
lution of bodies. 843. THE concretion of bodies is commonly solved by the contrary; as ice, which is congealed by cold, is dissolved by heat; salt and sugar, which are excocted by heat, are dissolved by cold and moisture. The cause is, for that these operations are rather returns to their former nature, than alterations ; so that the contrary cureth. As for oil, it doth neither easily congeal with cold, nor thicken with heat. The cause of both effects, though they be produced by contrary efficients, seemeth to be the same; and that
is, because the spirit of the oil by either means exhaleth little, for the cold keepeth it in; and the heat, except it be vehement, doth not call it forth. As for cold, though it take hold of the tangible parts, yet, as to the spirits, it doth rather make them swell than congeal them: as when ice is congealed in a cup, the ice will swell instead of contracting, and sometimes rift. Experiment solitary touching hard and soft bodies.
844. OF bodies, some we see are hard, and some soft: the hardness is caused chiefly by the jejuneness of the spirits, and their imparity with the tangible parts: both which, if they be in a greater degree, make them not only hard, but fragile, and less enduring of pressure; as steel, stone, glass, dry wood, etc. Softness cometh, contrariwise, by the greater quantity of spirits, which ever helpeth to induce yielding and cession, and by the more equal spreading of the tangible parts, which thereby are more sliding and following: as in gold, lead, wax, etc. But note, that soft bodies, as we use the word, are of two kinds ; the one, that easily giveth place to another body, but altereth not bulk, by rising in other places : and therefore we see that wax, if you put any thing into it, doth not rise in bulk, but only giveth place: for you may not think, that in printing of wax, the wax riseth up at all ; but only the depressed part giveth place, and the other remaineth as it was. The other that altereth bulk in the cession, as water, or other liquors, if you put a stone or any thing into them, they give place indeed easily, but then they rise all over; which is a false cession; for it is in place, and not in body. Experiment solitary touching bodies ductile and
tensile. 845. ALL bodies ductile and tensile, as metals, that will be drawn into wires; wool and tow, that will be drawn into yarn or thread, have in them the appetite of not discontinuing strong, which maketh them follow the force that pulleth them out; and yet so, as not to discontinue or forsake their own body. Viscous bodies likewise, as pitch, wax, birdlime, cheese toasted, will draw forth and rope.
the difference between bodies fibrous and bodies vis. cous is plain: for all wool, and tow, and cotton, and silk, especially raw silk, have, besides their desire of continuance, in regard of the tenuity of their thread, a greediness of moisture; and by moisture to join and incorporate with other thread; especially if there be a little wreathing; as appeareth by the twisting of thread, and the practice of twirling about of spindles. And we see also, that gold and silver thread cannot be made without twisting. Experiment solitary touching other passions of mat
ter, and characters of bodies. 846. THE differences of impressible and not impressible ; figurable and not figurable; mouldable and not mouldable ; scissile and not scissile; and many other passions of matter, are plebeian notions, applied unto the instruments and uses which men ordinarily practise; but they are all but the effects of some of these causes following, which we will enumerate without applying them, because that will be too long. The first is the cession, or not cession of bodies, into a smaller space or room, keeping the outward bulk, and not flying up. The second is the stronger or weaker appetite in bodies to continuity, and to fly discontinuity. The third is the disposition of bodies to contract, or not contract: and again, to extend, or not extend. The fourth is the small quantity, or great quantity of the pneumatical in bodies. The fifth is the nature of the pneumatical, whether it be native spirit of the body, or common air. The sixth is the nature of the native spirits in the body, whether they be active and eager, or dull and gentle. The seventh is the emission, or detention of the spirits in bodies. The eighth is the dilatation, or contraction of the spirits in bodies, while they are detained. The ninth is the collocation of the spirits in bodies, whether the collocation be equal, or unequal; and again, whether the spirits be coacervate, or diffused. The tenth is the density, or rarity of the tangible parts. The eleventh is the equality, or inequality of the tangible