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ancient coins of the towns of Segestas, Mottya, Drepanum, and Lilyboeum. A fine vase of white marble, with beautiful handles, and a foliage surrounding it, with other vases, and a ftatue of the god Par, are represented on the urth Plate. On the rzch we find the famous grotto of Sibylla, which is the excavation of a rock carried to the depth of eighteen feet, and discovers many vestiges of its ancient magnificence. Nothing can be more ingenious than the method our author bas followed in delireating this grotro, lo as to render both its outward form and its internal fructure difinály perceivable. There is a cborch built upon this grotto in honour of St. John of Jerusalem; but this change has not entirely effaced the reputation of the Sybil: For the eve preceding the Festival of St. John, the women, particularly in the lower claffes, come in crowds to consult the ancient prophetels; the matrons to learn wherber or no their husbands have been faithful to the marriage-bed during the past year; and maidens to enquire whether they shall get husbands in the course of the present ? To obtain the information they desire, they drink of the water that forms a canal at the bottom of the grotto, which, by the force of fancy, produces a kind of intoxication, and then they pronounce certain words, which this sonorous cavity sends back, modified by the echo of the place in various ways, which the supplicants understand as they can, and interpret as they chuse; and concluding, as suspicion, defire, or the caprice of the moment fuggeft, that their husbands are inconftant or faithful, direct their conduct accordingly. The Reader will find, in this second number, many interesting particularities relative to the manners and customs of the Sicilians; though some dem tails of this kind might be considerably abridged, and others fup.pressed, without impairing che merit of the work.

VI. Toberni Bergman Opuscula Phyfica, &c. Philosophical and Chemical Essays, &c. By Tobern Bergman, F.R. S. &c, Vol. II. Concluded. See Review for December last, p. 458.

DISSERTATION XVIII. On Platina. We shall select some of the Author's experiments on this fingular substance; in the course of which he was, in some mea. sure, successful : though it is still to be lamented that it remains 2 defideratum in chemištry to procure the easy fusion of this metal; which would be extremely valuable, could a method be discovered of melting it in such masses as might be manų. fa&tured.

In the Appendix to our 57th volume, p. 562, we took notice of a method discovered by M. Delisle, by which platina was said to be rendered more fusible, after it had been reduced to the state of a precipitate, thrown down from a solution of it in aqua regia, by means of fal ammoniac. The Author repeated this experiment with success; but only procured a malleable regulus, or metal, when he used a very small quantity of the precipicate, and a very intense fire. Employing the same precipitate, he even succeeded in melting it, merely by the heat produced by the blow pipe, with the addition of a little microcosmic falt. He thus obtained, in a few seconds, a pure, but small, tain whether it be a distinct metal, or a peculiar modification of iron, or a compound of various metallic substances formed by nature ; particularly, as some have thought, of cobalt, copper, and iron. He failed, however, in producing nickel; though he made various mixtures of these substances, and treated them both in the dry and humid way.

metallic

DissERTATION XXI. On Arsenic. This Dissertation contains many curious observations on this heteroclite substance, which is fo widely diffused throughout the mineral kingdom ; and, in its different states, appears under the various forms of a metal, a calx or earth, and a falt or acid. The white arsenic of the shops is in fact nothing more than an acid of a peculiar nature, different from every other known acid, and which contains just such a quantity of phlogiston as is sufficient to coagulate it. When a still greater quantity of phlogifton is added to, and combined with it, it becomes a metal.

According to the Author, ico parts of white arsenic contain 20 parts of phlogiston. When this principle has, by proper means, been totally expelled, the ar fenical acid is left pure. In that ftate, it becomes fixed in the fire; but, on being exposed to a moist air, it deliquefces, and at length is wholly resolved into a limpid Auid; having attracted to itself about two thirds of its weight of water.

It is nevertheless remarkable, that this pure acid, on being kept in a red heat, even in a close vessel, acquires, in some man. ner or another, as M. Scheele has shewn [Observations, &c. on Air, p. 53.) a certain portion of phlogiston, fufficient even to convert it into white arsenic. To account for this appearance of phlogiston, the Author adopts M. Scheele's fingular hypothesis, concerning the conftituent principles of heat or fore; according to which, the fire, which paffes freely through the fides of the retort, confifts of dephlogisticated air, and phlogiston : but within the body of the retort the fire is decomposed; its pirlogiston is attracted by the arsenical acid, with wbich it forms white arsenic; and its dephlogisticated air may be collected in a bladder fixed to the neck of the retort.

When the ar fenical acid has acquired as much phlogiston as is sufficient to saturate it completely, it then allumes, as we have above hinted, its third and last form, and becomes a metallic fubftance. From this fingular fact principally, and reasoning from analogy, the Author concludes, that it is probable that she different metals are nothing more than different acids, thoroughly coagulated with phlogiiton, although the connection of these two principles is, in general, so strong, that we are as yet ignorant of the proper means of destroying it: the calces of metals always abounding more or less with phlogiston.'-M. Scheele evidently inclines to the same opinion, and says were it pol

fible to separate the phlogiston, so firmly united with metallic earths, they would probably discover their acid nature more palpably.' [Obf. p. 107.]

Briefly enumerating the various uses of arsenic, the Author takes notice of the discovery of a new and excellent green colour, which undergoes ng change for many years, whether it be used as a water or an oil colour. It is a precipitate from a solution of blue vitriol, made by adding to it an aqueous solution of white arsenic and vegetable alcali.

One of the fingular qualities here mentioned of arsenic.is, that, on its being fused, in its metallic state, with iron, the compound metal, formed of these two substances, is not pofseffed of any magnetical qualities, though the quantity of iron contained in it be equal to that of the arsenic, or even constitute, in some cases, two thirds of the mass. On diffipating, however, a part of the arsenic by heat, though no phlogistic matter be present in the vessel, the iron recovers its magnetic powers.

DISSERTATION XXII. On the Ores of Zinc. One of the curious particulars contained in this Article is, that the Pseudogalena, one of the ores of this useful femi-metal, being treated either with vitriolic or marine acid, furnishes that particular species of air, first discovered by the Author, to which he gave the name of Hepatic Air, as having been originally produced from Hepar Sulphuris, and to which, it is evident, all the hot, and (as it now appears they have been juftly called) the sulphureous mineral waters, owe their principal médicinal efficacy. In our account of the Author's first volume [M. Review, Vol. LXII. January 1780, p. 74.), we described his method of discovering and precipitating the fulphur contained in these waters. In the present dissertation he describes

a method of exhibiting that subitance, when it exists under the | modification of hepatic air. This is effected by adding, to a

quantity of hepatic air contained in an inverted jar, an equal quantity of nitrous air. On their admixture, a real sulphur is precipitated from the first mentioned air; and a thermometer, included in the mixture of these two species of air, rises several degrees. We have formerly observed, that the Author's theory, with respeat to the constitution of hepatic air, is that it confifts of sulphur, combined with the matter of heat, through the medium of phlogiston. He here explains that idea more fully.

That it contains fulphur, is evident from the precipitation of that fubftance: that latent heat (calor ligatus] is likewise contained in it, is equally evident, he says, from the rising of the thermometer, which is caused by that heat being let loose, or becoming sensible heat : and that phlogiston (exclufive of that which is contained in the sulphur) is the bond which connects tain whether it be a distinct metal, or a peculiar modification of iron, or a compound of various metallic substances formed by nature ; particularly, as some have thought, of cobalt, copper, and iron. He failed, however, in producing nickel; though he made various mixtures of these substances, and treated them both in the dry and humid way.

DISSERTATION XXI. On Arfenic. This Dissertation contains many curious observations on this heteroclite substance, which is so widely diffused throughout the mineral kingdom ; and, in its different states, appears under the various forms of a metal, a calx or earth, and a falt or acid. 'The white arsenic of the shops is in fact nothing more than an acid of a peculiar nature, different from every other known acid, and which contains just such a quantity of phlogiston as is sufficient to coagulate it. When a still greater quantity of phlogiston is added to, and combined with it, it becomes a metal.

According to the Author, 100 parts of white arsenic contain 20 parts of phlogiston. When this principle has, by proper means, been totally expelled, the ar fenical acid is left pure. In that state, it becomes fixed in the fire; but, on being exposed to a moist air, it deliquesces, and at length is wholly resolved into a limpid fluid; baving attracted to itself about two thirds of its weight of water.

It is nevertheless remarkable, that this pure acid, on being kept in a red heat, even in a close vessel, acquires, in some man. ner or another, as M. Scheele has thewn [Observations, &c. on Air, p. 53.] a certain portion of phlogiłton, sufficient even to convert it into white arsenic. To account for this appearance of phlogiston, the Author adopts M. Scheele's fingular hypothesis, concerning the constituent principles of heat or fare; according to which, the fire, which paffes freely through the fides of the retort, consists of dephlogisticated air, and phlogiston : but within the body of the retort the fire is decomposed ; its phlogiston is attracted by the arsenical acid, with wbich it forms white arsenic; and its depblogisticated air may be collected in a bladder fixed to the neck of the retort.

When the arsenical acid has acquired as much phlogiston as is fufficient to saturate it completely, it then affumes, as we have above hinted, its third and last form, and becomes a metallic fubftance. From this singular fact principally, and reasoning from analogy, the Author concludes, that it is probable char the different metals are nothing more than different acids, thoroughly coagulated with phlogiston, although the connection of these two principles is, in general, so strong, that we are as yet ignorant of the proper means of destroying it: the calces of metals always abounding more or less with phlogiston.'-M. Scheele evidently inclines to the same opinion, and says were it polfible to separate the phlogiston, so firmly united with metallic earths; they would probably discover their acid nature more palpably.' [Of. p. 107.]

Briefly enumerating the various uses of arsenic, the Author takes notice of the discovery of a new and excellent green colour, which undergoes ng change for many years, whether it be used as a water or an oil colour. It is a precipitate from a solution of blue vitriol, made by adding to it an aqueous solution of white arsenic and vegetable alcali.

One of the fingular qualities here mentioned of arsenic is, that, on its being fused, in its metallic state, with iron, the compound metal, formed of these two substances, is not poffeffed of any magnetical qualities, though the quantity of iron contained in it be equal to that of the arsenic, or even constitute, in some cases, two thirds of the mass. On diffipating, however, a part of the arsenic by heat, though no phlogistic matter be present in the vessel, the iron recovers its magnetic powers.

DISSERTATION XXII. On the Ores of Zinc. One of the curious particulars contained in this Article is, that the Pseudogalena, one of the ores of this useful femi-metal, being treated either with vitriolic or marine acid, furnishes that particular species of air, first discovered by the Author, to which he gave the name of Hepatic Air, as having been originally produced from Hepar Sulphuris, and to which, it is evident, all the hot, and (as it now appears they have been juftly called) the fulphureous mineral waters, owe their principal médicinal efficacy. In our account of the Auihor's first volume (M. Review, Vol. LXII. January 1780, p. 74.), we described his method of discovering and precipitating the sulphur contained in these waters. In the present dissertation he describes a method of exhibiting that subítance, when it exists under the modification of hepatic air. This is effected by adding, to a quantity of hepatic air contained in an inverted jar, an equal quantity of nitrous air. On their admixture, a real sulphur is precipitated from the first mentioned air; and a thermometer, included in the mixture of these two species of air, rises several degrees. We have formerly observed, that the Author's theory, with respect to the conftitution of hepatic air, is that it confifts of fulphur, combined with the matter of heat, through the medium of phlogiston. He here explains that idea more fully.

That it contains fulphur, is evident from the precipitation of that substance: that latent heat (calor ligatus] is likewise contained in it, is equally evident, he says, from the rising of the thermometer, which is caused by that heat being let loose, or becoming sensible heat: and that phlogiston (exclufive of that which is contained in the fulphur) is the bond which connects

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