parable nature of gold, it being excluded in the same quantity as it was received, without alteration of parts, or diminution of its gravity.

Now, herein to deliver somewhat, which in a middle way may be entertained: we first affirm, that the substance of gold is invincible by the powerfullest action of natural heat; and that not only alimentally in a substantial mutation, but also medicamentally in any corporeal conversion; as is very evident, not only in the swallowing of golden bullets, but in the lesser and foliate divisions thereof; passing the stomach and guts even as it doth the throat, that is, without abatement of weight or consistence; so that it entereth not the veins with those electuaries wherein it is mixed; but taketh leave of the permeant parts, at the mouths of the mesaraicks, or lacteal vessels, and accompanieth the inconvertible portion unto the siege. Nor is its substantial conversion expectable in any composition or aliment wherein it is taken. therefore that was truly a starving absurdity which befel the wishes of Midas. And little credit there is to be given to the golden hen, related by Wendlerus. And so in the extinction of gold, we must not conceive it parteth with any of its salt or dissoluble principle thereby, as we may affirm of iron; for the parts thereof are fixed beyond division; nor will they separate upon the strongest test of fire. This we affirm of pure gold; for that which is current and passeth in stamp amongst us, by reason of its alloy, which is a proportion of silver or copper mixed therewith, is actually dequantitated by fire, and possibly by frequent extinction.

And

Secondly, although the substance of gold be not immuted, or its gravity sensibly decreased, yet that from thence some virtue may proceed either in substantial reception or infusion, we cannot safely deny. For possible it is that bodies may emit virtue and operation without abatement of weight; as is most evident in the loadstone, whose effluencies are continual and communicable without a minoration of gravity; and the like is observable in bodies electrical, whose emissions are less subtile. So will a diamond or sapphire emit an effluvium sufficient to move the needle or a straw, without diminution of weight. Nor will polished amber, although it send forth a gross and corporeal exhalement, be found a long time defective upon the exactest scales; which

is more easily conceivable in a continued and tenacious effluvium, whereof a great part retreats into its body.

Thirdly, if amulets do work by emanations from their bodies, upon those parts whereunto they are appended, and are not yet observed to abate their weight; if they produce visible and real effects by imponderous and invisible emissions, it may be unjust to deny the possible efficacy of gold, in the non-omission of weight, or deperdition of any ponderous particles.8

Lastly, since stibium, or glass of antimony, since also its regulus will manifestly communicate unto water or wine a purging and vomitory operation, and yet the body itself, though after iterated infusions, cannot be found to abate either virtue or weight: we shall not deny but gold may do the like, that is, impart some effluences unto the infusion, which carry with them the separable subtilities thereof.9

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some

8 Thirdly, if amulets, &c.] This paragraph is so cautiously worded, by virtue of the little if, as to convey a proposition at once safe and undeniable. But, like many other cautious propositions, it says nothing. The questions remain, what amulets do "produce visible and real effects?"-whether these "work by emanations?"-and whether they do so without "abating their weight?" Though the Hon. Robt. Boyle was pleased to attribute the cure of an hæmorrhage to wearing moss from a dead man's skull," our readers will probably be inclined to indulge a good deal of scepticism as to the efficacy of such charms. Camphor, volatile alkali, pungent acids, &c. which are often used, and perhaps efficaciously, as repellents of contagion, can scarcely be termed amulets; and if they are so, they most certainly do not come within Sir Thomas's definition, as "not abating their weight by emanations." The Abbé Pluche speaks of the origin of amulets, properly so called, in his Histoire du Ciel, 12mo. tom. i. p. 360. See also a very curious little work on amulets, by Petr. Frid. Arpe, entitled De prodigiosis Naturæ et Artis Operibus Talismanes et Amuleta dictis, 12mo. Hamburgi, 1717.

9 Lastly, since stibium, &c.] The antimoniall cupp was anciently in domestic medicine, on the double principle here stated, by which the metal, without losing its bulk, imparted to the wine poured into it the desired property. There occurs in the Gentleman's Magazine (vol. CII. pt. i. p. 581), a curious account of one of these "cupps." It is made of the regulus of antimony, cast in a mould; is about two inches high by about as many in diameter, and holds about four ounces; is contained in a leathern box; within are written directions for its use, prefaced by a full announcement of the "vertues of the cupp," together with some Latin and English verses. The process of preparing the cup for use

That therefore this metal thus received hath any undeniable effect, we shall not imperiously determine, although, beside the former experiments, many more may induce us to believe it. But, since the point is dubious and not yet authentically decided, it will be no discretion to depend on disputable remedies; but rather, in cases of known danger, to have recourse unto medicines of known and approved activity. For, beside the benefit accruing unto the sick, hereby may be avoided a gross and frequent error, commonly committed in the use of doubtful remedies conjointly with those which are of approved virtues, that is, to impute the cure unto the conceited remedy, or place it on that whereon they place their opinion; whose operation, although it be nothing, or its concurrence not considerable, yet doth it obtain the name of the whole cure, and carrieth often the honour of the capital energy, which had no finger in it.

Herein exact and critical trial should be made by public enjoinment, whereby determination might be settled beyond debate; for, since thereby not only the bodies of men, but great treasures might be preserved, it is not only an error of physics, but folly of state, to doubt thereof any longer.1

4. That a pot full of ashes will still contain as much water as it would without them, although by Aristotle in his problems taken for granted, and so received by most, is not effectable upon the strictest experiment I could ever make. For when the airy interstices are filled, and as much of the salt of the ashes as the water will imbibe is dissolved, there remains a gross and terreous portion at the bottom, which will possess a space by itself, according whereto, there will remain a quantity of water not receivable: so will it come to pass in a pot of salt, although decrepitated:2 and so also in a pot of snow; for so much it will want in reception, as its solution taketh up, according unto the bulk whereof, there will remain a portion of water not to be admitted: so a was either by letting wine stand for a certain time in it, or (if it was required to antimonize more wine than the cup would contain), by plunging the cup into the requisite quantity of wine. Regulus of antimony was also anciently used in the form of pills, which, it is asserted, were, by some frugal persons, re-employed as often as they could be recovered!

1 Herein, &c.] Added in the 2nd edition.

2

decrepitated.] Calcined till it has ceased to crackle.

glass stuffed with pieces of sponge will want about a sixth part of what it would receive without it: so sugar will not dissolve beyond the capacity of the water, nor a metal in aqua fortis be corroded beyond its reception; and so a pint of salt of tartar, exposed unto a moist air until it dissolve, will make far more liquor, or, as some term it, oil, than the former measure will contain.

Nor is it only the exclusion of air by water, or repletion of cavities possessed thereby, which causeth a pot of ashes to admit so great a quantity of water, but also the solution of the salt of the ashes into the body of the dissolvent: so a pot of ashes will receive somewhat more of hot water than of cold, for the warm water imbibeth more of the salt; and a vessel of ashes more than one of pin-dust or filings of iron; and a glass full of water will yet drink in a proportion of salt or sugar without overflowing.

Nevertheless, to make the experiment with most advantage, and in which sense it approacheth nearest the truth, it must be made in ashes thoroughly burnt and well reverberated by fire, after the salt thereof hath been drawn out by iterated decoctions. For then the body, being reduced nearer unto earth, and emptied of all other principles, which had former ingression unto it, becometh more porous, and greedily drinketh in water. He that hath beheld what quantity of lead the test of saltless ashes will imbibe, upon the refining of silver, hath encouragement to think it will very much more in water.3

do

5. Of white powder, and such as is discharged without report, there is no small noise in the world; but how far agreeable unto truth, few, I perceive, are able to determine. Herein therefore, to satisfy the doubts of some and amuse

3 Nevertheless, &c.] Added in 2nd edition.

45 Of white powder, &c.] The nearest approach to white powder is the fulminating powder, in which carbonate of potash is substituted for charcoal the composition being three parts of nitre, two of carbonate of potash, and one of sulphur.-Ure's Dictionary of Chemistry.

But this detonates more loudly than gunpowder. The error which it was our author's object to correct here, was that of expecting an effective gunpowder (of whatever colour) which should be "without report." He justly observes, that, even admitting the probability of making a "white powder,""-"and such an one as may give no report,"-it would "be of little force, and the effects thereof no way to be feared."

the credulity of others, we first declare, that gunpowder consisteth of three ingredients, saltpetre, small-coal, and brimstone. Saltpetre, although it be also natural and found in several places, yet is that of common use an artificial salt, drawn from the infusion of salt earth, as that of stales, stables, dove-houses, cellars, and other covered places, where the rain can neither dissolve, nor the sun approach to resolve it: brimstone is a mineral body of fat and inflammable parts, and this is either used crude, and called sulphur vive, and is

5

6

we first declare, &c.] The account here given of gunpowder is upon the whole accurate; especially if we allow for the unsettled state of philosophical language at that time, which makes it sometimes difficult to feel assured of Sir Thomas's precise meaning. He was evidently aware of the necessity of employing pure ingredients in the composition of gunpowder; observing that " 'powder which is made of impure and greasy petre hath but a weak emission, and giveth a faint report ;" and again, "that the best way to alter the noise and strength of the discharge, consists in the quality of the nitre." He assigns, with sufficient correctness, to its constituents their respective share in the general results, when he ascribes to the charcoal the "quick accen sion [ignition]" to the sulphur the "piercing and powerful firing,” and to the nitre the "force and the report."-Modern experiment has shown that the detonation or explosion of gunpowder is attributable to the nitre, when combined with inflammable substances, viz. the sulphur and charcoal; and arises from the sudden extrication, by combustion, of nitrogen and carbonic acid gases, which expand to a volume about two thousand times greater than that originally occupied by the powder.— The opinions of Carden and Snellius, quoted by our author, as to the degree of expansion, are erroneous. In describing the mixture of the three ingredients of gunpowder, Sir Thomas has named proportions very different from those now adopted. Barrow informs us, that the Chinese soldiery make their gunpowder (for it is there the duty of every soldier to prepare his own) in the proportion of 50lbs. of nitre to 25lbs. each of sulphur and charcoal: but the modern practice is to employ about 75 of nitre and 15 (or 16) of charcoal to 10 (or 9) of sulphur; varying the relations between the two last, according as the object is to produce a powder of greater durability or of greater strength; more usually the sulphur has been increased, and the carbon lessened-in order to obtain a more lasting article, by a slight sacrifice of strength-which may readily be compensated by increasing the charge.

6 Saltpetre, although it be also natural, &c.] Native saltpetre, or nitre (nitrate of potash) occurs in crusts and capillary crystals, in Spain, France, Italy, and Hungary; in Arabia, Persia, and India; at the Cape of Good Hope, in the mountains of Kentucky, and near Lima in South America. But not being naturally produced in sufficient quantity, it is obtained artificially, in what are termed nitre-beds, as is described by Thenard (Traité de Chimie, ii. 511.)