« НазадПродовжити »
can resist their force; and the agitation of ed its lowest protuberances; and that, lastly, the air which they produce is so violent that immediately after this revolution, the ridge of the every obstacle to their progress is overturned. primitive formation was, without doubt, at the In the neighbourhood of Baréges whole villages same time that of the whole chain of the Pyrehave sometimes been thus overwhelmed.
No country is richer in natural productions Now, as we observe at the present day that than that of the Pyrenees; the geologist may find the ridge of the Pyrenees, with the exception of here numberless beauties, and ever fresh sources a small number of places, is no longer the ridge of instruction; the mineralogist a multitude of of the granitic chain, which is found removed at the most cnrious minerals; the botanist, passing some distance to the north ; but that this geograin the same day from the greatest heat to the phic ridge is composed of more modern rocks, most intense cold, meets in his way every species which generally surpass the primitive formation of plants, from those which grow in the Alps and in height, we are naturally led to presume that in Sweden to those which flourish in Spain. In the Pyrenees have undergone a second very conthe middle part mineral springs abound; but, siderable degradation. The disposition of the though some are of great efficacy, they are little rocks, and the external form of the mountains, used.
The most celebrated, and which have appear to determine the period of this revolution. establishments greatly frequented, are the baths It is probable that it has taken place after the of Molitg, Baréges, Bagneres, Arles, Vernet, La formation of the transition deposite, and before Preste, Ax, Cambo, Cauterets, Nossa, Olette, the excavation of the presently existing valleys, Nyer, and the warm springs of the Cerdagne, and consequently before the deposition of the generally known by the name of Lascaldas. trap formation, which, as we shall see in the se
Since the above has been prepared for press quel, appears to be of a very late origin. our attention has been directed to the Geological Observation tends to induce a presumption Conjectures of Mr. Charpentier, director of the that this degradation has principally attacked the Canton de Vaud mines, respecting the original ridge then existing, and all the northern aspect form and construction of the Pyrenees. The fol- of the chain. We shall represent by a diagram lowing is an abstract of them as given in his the results which have given rise to this suppoEssai sur la Constitution Geogrostique des Py- sition. renees, a very sensible and distinguished per • The figure shows the vertical and transverse formance.
A We have seen,' says this writer, that the different formations are disposed in bands parallel to each other and parallel to the general direction of the Pyrenees ; that the granite forms only a single band, or, speaking more correctly, a chain or series of protuberances; that each of the other formations constitutes in general two bands, one of which is situated to the north, the other to the south of the granitic chain, resting upon it in the order of their relative antiquity; that many of these granitic protuberances are separated from one ano- section A B C of the Pyrenees in the direction ther by valleys, while others, on the contrary, of their breadth, such as we presume it to have are, as it were, agglutinated by rocks of later been before these mountains underwent the deorigin, which have filled up the spaces or vacui- gradation of which we have been speaking. We ties by which they were formerly separated; see in this section the two declivities A B and and, lastly, that it is commonly in the spaces A D of equal size; the granite occupying the which exist between two great protuberances that centre, and forming the ridge of the chain
; the we observe the bands that occur to the south of transition formation, and the secondary formathe granitic chain, touching and mingling with tion, distributed in nearly equal quantities upon those which occur to the north. These facts en the south and north sides, resting upon the gratitle us to presume that the granitic formation, nite. Let us now suppose that all the portion comprising that of mica-slate and primitive lime- of these mountains situated between A, B, and stone, formed originally an uninterrupted chain, C, has been destroyed by the effect of some or rather an elongated line, having a direction power acting from north to south, in such a from south-east to north-west, and being of a manner that there remains only the part situated height, whether absolute or relative, much greater between C, B, and D. than at the present day; that at a period ante *The necessary consequence of this degradarior to the formation of the other rocks which tion would be a considerable change in the exrecline upon it, this granitic chain has undergone ternal form of the whole chain of mountains, and degradations caused by a power (perhaps currents especially in the disposition and distribution of of water) which, acting horizontally from south the rocks with relation to the external form of the to north, or from north to south, has broken its chain; in short, this revolution would produce ridge in many parts, scooped it out to a great a multitude of results and accidents which are depth, and changed it into a series of more or observed in the Pyrenees, and of which we shall less isolated eminences; that the rocks formed recapitulate the chief. after this revolution have been applied on each • There would result from the destruction of side against this central granitic chain, have fill- all the parts situated between A, B, and C, 1st, ed up its deepest hollows, and have even cover- That the ridge would be lowered ; and, further,
that its position would be removed more to the the end of the calcination a brownish vapor is south, and that consequently the northern aspect seen to form, and there remains in the bottom B, C, would become longer and more sloping of the retort a light very brilliant charcoal. than the southern one B D. 2dly, That the gra The product contained in the receiver consists nite, including the other primitive rocks, would of two different liquids. One of an amber-yelno longer form the ridge of the central chain, to low color, and an oily aspect, occupies the lower the north of which it would occur at a short part; another, colorless, and liquid like water, of distance. 3dly, That the southern bands of the a very decided acid taste, floats above. After secondary and transition formations would ob- separating them from one another, we perceive tain a height which would in general surpass that the first has a very strong bituminous odor, that of the granite and that of all the other and an acid and acrid taste; that it reddens rocks situated to the north of the primitive powerfully the tincture of litmus, but that it formation. 4thly, That these two southern may be deprived almost entirely of that acidity bands would, in general, form the ridge of by agitation with water, in which it divides itthe whole system. 5thly, That the transition self into globules, which soon fall to the bottom formation would be much more diffused, or, at of the vessel, and are not long in uniting into least, would appear to a much greater extent, one mass, in the manner of oils heavier than water. upon the north side than upon the southern de In this state it possesses some of the proclivity. 6thly, That the secondary formation perties of these substances; it is soluble in alwould occupy all the southern declivity, while, cohol, ether, and the caustic alkalis. However, on the northern side, it would only form the low it does not long continue thus; it becomes acid, mountains at the foot of the chain.
and sometimes even it is observed to deposit, at “We here see how well the necessary results the end of some days, white crystals, which of the supposition which we have admitted ac have a very strong acidity; if we then agitate it cord with the actual phenomena. Several other
anew with water, it dissolves in a great measures observations would further lead us to presume, and abandons a yellow or brownish pitchy matthat, independently of the great revolution of ter, of a rery obvious empyreumatic smell, and which we have been speaking, the northern part which has much analogy with the oil obtained of the Pyrenees must have undergone, previously in the distillation of other vegetable matters. to the formation of the present valleys, a new The same effect takes place when we keep it degradation of considerable extent; such, for under water; it diminishes gradually in volume, example, are the generally softer and inore round- the water acquires a sour taste, and a thick oil ed forms of the northern, compared with the remains at the bottom of the vessel. southern mountains; the more considerable This liquid may be regarded as a combination numher of basins in the French valleys than in (of little permanence indeed) of the peculiar those of the Spanish side; and the immense de- acid with the oil formed in similar circumposites of transported rocks, of which the soil of stances. the plains which extend from the north side of This acid is white, inodorous, of a strongly the Pyrenees is formed.'
acid taste. It is difficult to make it crystallise PYRIFORMIS, banksia, in botany, a species in a regular manner, but it is usually presented of Banksia, which see. It was unknown to in a white mass, formed by the interlacement of Linné; and Gaertner, who has mentioned it, very fine small needles. Projected on a hot gives no specific character of it. It has solitarybody it melts, is converted into white very punflowers, ovate downy capsules, and lance-shaped gent vapors, and leaves some traces of carbon. entire smooth leaves : caps. larger than in any When heated in a retort, it affords an oily-lookother known species.
ing acid, and yellowish liquid, and is partially PYRMONT, a district in the north-west of decomposed. It is very soluble in water and in Germany, between Hanover in the north, and the alcohol; water at the temperature of 10° C. Prussian government of Minden, in Westphalia, (50° F.) dissolves one-third of its weight. The in the south. It belongs to prince Waldec, with watery solution has a strongly acid taste, it does the title of a county, but has an area of only not precipitate lime or barytes water, nor the thirty-six square miles, with 4300 inhabitants ; greater part of metalliq solutions, with the ex. of the prince's income (about £10,000), the larger ception of acetate of lead and protonitrate of half arises from the mineral springs of
mercury. With the oxides it forms salts posPYRMONT, the chief town of the above princi- sessing properties different from the citrates. pality. It contains 2000 inhabitants, and is situ. The pyrocitrate of potash crystallises in small ated in a pleasant valley, with public walks, and needles, which are white, and unalterable in the houses adapted to the accommodation of visitors. air. It dissolves in about four parts of water. Thirty-three miles S. S. W. of Hanover, and six- Its solution gives no precipitate with the nitrate teen south-east of Rinteln.
of silver, or of barytes ; whilst that of the citrate PYROCITRIC Acid, in chemistry: When of barytes forms precipitates with these salts. citric acid is put to distil in a retort, it begins at The pyrocitrate of sime directly formed exhifirst by melting ; the water of crystallisation sepa- bits a white crystalline mass, composed of needles, rates almost entirely from it by a continuance of. opposed to each other in a ramification form. the fusion; then it assumes a yellowish tint, This salt has a sharp taste. which gradually deepens. At the same time PYROLA, in botany, winter green, a genus there is disengaged a white vapor which goes of the monogynia order, and decandria class of over, to be condensed in the receiver, Towards plants; natural order eighteenth, bicornes: CAL.
quinque partite; petals five: caps. is quinque- water, yields brilliant pearly looking needles. locular, opening at the angles.
The white crystals that sublime in the original PYROLIGNEOUS Acid, in chemistry, is the distillation are considered by M. Lassaigne as a destructive distillation of any kind of wood an peculiar acid. acid is obtained, which was formerly called acid PYROMETER, from rup, fire, and perpov, spirit of wood, and since pyroligneous acid. measure. To measure those higher degrees of Fourcroy and Vauquelin showed that this acid heat to which the thermometer cannot be apwas merely the acetic, contaminated with empy- plied there have been other instruments invented reumatic oil and bitumen. See ACETIC ACID, by different philosophers: these are called pyroCHEMISTRY, and VINEGAR.
meters. The most celebrated instrument of this PYROLITHIC Acid, in chemistry. When kind, and which has been adopted into genera! uric acid concretions are distilled in a retort, usė, is that invented by the late ingenious Mr. silvery white plates sublime. These are pyroli Wedgwood. thate of ammonia. When their solution is This instrument is also sufficiently simple. poured into that of subacetate of lead, a pyroli- It consists of two pieces, of brass fixed on a plate, thate of lead falls, which, after proper washing, so as to be six-tenths of an inch asunder at one is to be shaken with water, and decomposed by end, and three-tenths at the other; a scale is sulphureted hydrogen gas. The supernatant marked upon them, which is divided into 240 liquid is now a solution of pyrolithic acid, which equal parts, each one-tenth of an inch; and with yields small aaicular crystals by evaporation. this his gauge, are furnished a sufficient number By heat, these melt and sublime in white needles. of pieces of baked clay, which must have been They are soluble in four parts of cold water, and prepared in a red heat, and must be of given dithe solution reddens vegetable blues. Boiling mensions. These pieces of clay, thus prepared, alcohol dissolves the acid, but on cooling it de- are first to be applied cold to the rule of the posits it, in small white grains. Nitric acid dis gauge, that there inay no mistake take place in solves without changing it. Hence, pyrolithic regard to their dimensions. Then any one of is a different acid from the lithic, which, by them is to be exposed to the heat which is to be nitric acid, is convertible into purpurate of am measured, till it shall have been completely pemonia. The pyrolithate of lime crystallises in netrated by it. It is then removed and applied stalactites, which have a bitter and slightly acrid to the gauge. The difference between its former taste. It consists of 91.4 acid + 8.6 lime. Py- and its present dimensions will show how much rolithate of barytes is a nearly insoluble powder. it has shrunk; and will consequently indicate to The salts of potassa, soda, and ammonia, are what degree the intensity of the heat to which it soluble, and the former two crystallisable. At a was exposed amounted. red heat, and by passing it over ignited oxide of High temperatures can thus be ascertained copper, it is decomposed, into oxygen 44:32, with accuracy. Each degree of Wedgwood's carbon 28.29, azote 16 84, hydrogen 10.' pyrometer is equal to 130° of Fahrenheit's.
PYROMALIC Acid, in chemistry, when Mr. Wedgwood sought to establish a corremalic or sorbic acid, for they are the same, is spondence between the indications of his pyromedistilled in a retort, an acid sublimate, in white ter and those of the mercurial thermometer, by needles, appears in the neck of the retort, and employing a heated rod of silver, whose expanan acid liquid distils into the receiver. This sions he measured, as their connecting link. The liquid, by evaporation, affords crystals, consti- clay-piece and silver rod were heated in a tuting a peculiar acid, to which the above name muffe. has been given.
When the muffle appeared of a low red heat, They are permanent in the air, melt at 118° such as was judged to come fully within the Fahrenheit, and on cooling form a pearl-colored province of the thermometer, it was drawn formass of diverging needles. When thrown on ward toward the door of the oven; and, its own red-hot coals, they completely evaporate in an door being then nimbly opened by an assistant, acrid, cough-exciting smoke. Exposed to a Mr. Wedgwood pushed the silver piece as far as strong heat, in a retort, they are partly sublimed it would go. But, as the division which it went in needles, and are partly decomposed. They to could not be distinguished in that ignited are very soluble in strong alcohol, and in dou- state, the muffle was lifted out, by means of an ble their weight of water, at the ordinary tem- iron rod passing through two rings made for that perature. The solution reddens vegetable blues, purpose with care to keep it steady, and avoid and yields white flocculent precipitates with any shake that might endanger the displacing of acetate of lead and nitrate of mercury; but pro- the silver piece. duces no precipitate with lime water. By When the muffle was grown sufficiently cold mixing it with barytes water, a white powder to be examined, he noted the degree of expanfalls, which is redissolved by dilution with water, sion which the silver piece stood at, and the deafter which, by gentle evaporation, the pyroma- gree of heat shown by the thermometer pieces late of barytes may be obtained in silvery plates. measured in their own gauge; then returned These consist of 100 acid, and 185142 barytes, the whole into the oven as before, and repeated or, in prime equivalents, of 5.25 + 9.75. the operation with a stronger heat, to obtain ano
Pyromalate of potash may be obtained in ther point of correspondence on the two scales. feather formed crystals, which deliquesce. Py The first was at 21° of his thermometer, which romalate of lead forms first a white flocculent coincided with 66° of the intermediate one; and, precipitate, soon passing into a semi-transparent as each of these last had been before found to jelly, which, by dilution and filtration from the contain 20° of Fahrenheit's, the 66° will contain
1320; to which add 50, the degree of his scale The point at which mercury to which the (0) of the intermediate thermometer congeals, consequently the was adjusted, and the sum 1370 will be the limit of mercurial therdegree of Fahrenheit's corresponding to his 27°. mometers, about
8 PA The second point of coincidence was at 61° PYROMUCIC ACID. This acid, discovered of his, and 920 *of the intermediate; which 92° in 1818 by M. Houton Labillardière, is one of being, according to the above proportion, equi- the products of the distillation of mucic acid. valent to 1840 of Fahrenheit, add 50 as before When we wish to procure it, the operation must to this number, and his 67° is found to fall upon be performed in a glass retort furnished with a the 1890° of Fahrenheit.
receiver. The acid is formed in the brown It appears hence that an interval of 4° upon liquid, which is produced along with it, and Mr. Wedgwood's thermometer is equivalent to which contains water, acetic acid, and empyreuan interval of 520° upon that of Fahrenheit; matic oil; a very small quantity of the pyroand, consequently, one of the former to 130° of mucic acid remaining attached to the vault of the latter; and that the (0) of Mr. Wedgwood the retort under the form of crystals. These corresponds to 1077]° of Fahrenheit.
crystals, being colored, are added to the brown From these data it is easy to reduce either liquor, which is then diluted with three or four scale to the other through their whole range ; times its quantity of water, in order to throw and from such reduction it will appear, that an down a certain portion of oil. The whole is interval of nearly 480° remains between them, next filtered, and evaporated to a suitable dewhich the intermediate thermometer serves as a gree. A great deal of acetic acid is volatilised, measure for; that Mr. Wedgwood's includes and then the new acid crystallises. On decantan extent of about 32,000 of Fahrenheit's degrees, ing the mother waters, and concentrating them or about fifty-four times as much as that between farther, they yield crystals anew; but, as these the freezing and boiling points of mercury, by are small and yellowish, it is necessary to make which mercurial ones are naturally limited; that them undergo a second distillation to render if the scale of Mr. Wedgwood's thermometer them susceptible of being perfectly purified by be produced downward in the same manner as crystallisation ; 150 parts of mucic acid furnish Fahrenheit's has been supposed to be produced about sixty of brown liquor, from which we can upward, for an ideal standard, the freezing point obtain eight to ten of pure pyromncie acid. of water would fall nearly on 8° below (i) of This acid is white, inodorous, of a strongly Mr. Wedgwood's, and the freezing point of acid taste, and a decided action on litmus. Exmercury a little below 8;°; and, that, therefore, posed to heat in a retort it melts at the temperaof the extent of now measurable heat, there are ture of 266° Fahrenheit, then volatilises, and about five-tenths of a degree of his from the condeuses into a liquid, which passes on coolfreezing of mercury to the freezing of water; 8° ing into a crystalline mass, covered with very from the freezing of water to full ignition; and fine needles. It leaves very slight traces of ré160° above this to the highest degree he has hi- siduum in the bottom of the retort. therto attained.
On burning coals, it instantly diffuses while Mr. Wedgwood concludes his account with pungent vapors. Air has no action on it. Wathe following table of the effects of heat on dif- ter at 60o dissolves one-twenty-eighth of its ferent substances, according to Fahrenheit's ther- weight. Boiling water dissolves it much more mometer and his own :
abundantly, and on cooling abandons a portion
of it, in small elongated plates, which cross in Fahr. Wedg.
every direction. Extremity of the scale of
PÝROPHORUS. By this name is denoted his thermometer
322770 240 an artificial product, which takes fire or becomes Greatest heat of his small
ignited on exposure to the air. Hence, in the air furnace
21877 160 German language, it has obtained the name of Cast-iron melts
17977 130 luft-zunder, or air-tinder. It is prepared from Greatest heat of a common
alum by calcination, with the addition of various smith's forge
inflammable substances. Homberg was the first Welding heat of iron greatest 13427 95 that obtained it, which he did accidentally in the Welding heat of iron least. 12777 90 year 1680, from a mixture of human excrement Fine gold melts
5237 32 and alum, upon which he was operating by fire. Fine silver melts.
4717 28 The preparation is managed in the following Swedish copper melts
4587 27 manner :—Three parts of alum are mixed with Brass melts
3807 91 from two to three parts of honey, flour, or sugar; Ileat by which his enamel
and this mixture is dried over the fire in a glazed colors are burnt on
1857 6 bowl, or an iron pan, diligently stirring it all the Red heat fully visible in
while with an iron spatula. At first this mixture day-light
1077 0 melts, but by degrees it becomes thicker, swells Red heat fully visible in the
up, and at last runs into small dry lumps. These dark
are triturated to powder, and once more roasted Mercury boils .
over the fire, till there is not the least moisture Water boils
remaining in them, and the operator is well asVital heat
97 7 sured that it can liquefy no more: the mass now Water freezes
32 Toko looks like a blackish powder of charcoal. For Proof spirit freezes
the sake of avoiding the previous above men
tioned operation, from four to five parts of upon this the calcination must be put an end 10, burned alum may be mixed directly with two of and the phial closed for a short time with a charcoal powder. This powder is poured into a stopper of clay or loam. But, as soon as the phial or matrass, with a neck about six inches vessel is become so cool as to be capable of long. The phial, which however must be being held in the hand, the phial is taken out of filled three-quarters full only, is then put into a the sand, and the powder contained in it transcrucible, the bottom of which is covered with ferred as fast as possible from the phial into a sand, and so much sand is put round the former dry and stout glass made warm, which must be that the upper part of its body also is covered secured with a glass stopper. with it to the height of an inch: upon this the We have made a very good pyrophorus by crucible, with the phial, is put into the furnace, simply mixing three parts of alum with one of and surrounded with red-hot coals. The fire, wheat-flour, calcining them in a common phial being now gradually increased till the phial be- till the blue fame disappeared ; and have kept comes red-hot, is kept up for the space of about it in the same phial, well stopped with a good a quarter of an hour, or till a black smoke ceases cork when cold. to issue from the mouth of the phial, and instead If this powder be exposed to the atmosphere, of this a sulphureous vapor exhales, which com- the sulphuret attracts moisture from the air, and monly takes fire. The fire is kept up till the generates sufficient heat to kindle the carbonaceblue sulphureous flame is no longer to be seen ; ous matter mingled with it.
PYROTECH N Y.
PYRÄOTECHNY, n. s. Fr. pyrotechnie. The other pyrotechnical inventions, much more brilart of managing fire, or making fire-works. liant than when gunpowder, or the substances of
Great discoveries have been made by the means of which it is composed, are alone employed. Nopyrotechny and chymistry, which in late ages have thing is necessary but to take iron filings, very attained to a greater height than formerly.
clean and free from dust, and to mix them with Hale's Origin of Mankind. the ordinary composition. It must, however,
be observed, that works of this kind will not PYROTECHNY, of Greek. Trup, fire, and texvn, keep longer than a week; because the moisture art, is a term that has been applied to all kinds contracted by the saltpetre rusts the iron filings. of artificial fire-works, including those of a mili The Chinese have long been in possession of tary description ; but of late it has been more
a method of rendering this tire much more brilcommonly restricted to those fire-works which liant and variegated in its colors; and we are are constructed for amusement, or are used in indebted to father d'Incarville, a jesuit, for having public demonstrations of joy: and it is in this made it known. It consists in the use of a simsense we shall consider it in this article.
ple ingredient, namely, cast iron reduced to a These are inventions which, though they seem powder more or less fine: the Chinese gave it to have been for ages familiar to the Chinese and
a name which is equivalent to that of iron sand. other nations of the eastern world, were brought at To prepare this sand take an old iron pot, and, a recent period only into Europe by way of Italy; having broken it to pieces on an anvil, pulverise and the Italian and French artists long bore the fragments till the grains are not larger than away the palm in their construction. The late radish seed; then sift them through six graduated Sir William Congreve, however, at the period of sieves, to separate the different sizes; and prethe peace of 1815, seemed suddenly toʻrise like
serve these six different kinds in a very dry place, one of his own rockets, above our foreign com
to secure them from rust, which would render petitors ; and with the aid of his majesty's parks, this sand absolutely unfit for the proposed end. the public purse, the sheet of water in St. We must here remark that the grains which pass James's park, and the never-to-be-forgotten Chi- through the closest sieve are called sand of the nese bridge over the said water, to have attained first order ; those which pass through the next the most brilliant honors in this art. We believe in size, sand of the second order.; and so on. all his principal devices will be found included
This sand, when it inflames, emits a light exin the descriptive account of modern fire-works ceedingly vivid. It is very surprising to see here following :
fragments of this matter no bigger than a poppy
seed form all on a sudden luminous Rowers or PART I.
stars, twelve and fifteen lines in diameter. These SMALLER AND MISCELLANEOUS FIRE. Aowers are also of different forms, according to
that of the inflamed grain, and even of different WORKS.
colors, according to the matters with which the 1. Of the Chinese fire.--In honor of the Chinese grains are mixed. Rockets which contain the we begin with the brilliant fire sometimes called finest sand will not keep longer than eight days, Chinese fire. Iron filings, when thrown into the and those which contain the coarsest, fifteen. fire, inflame and emit a strong light. This pro- The following tables exhibit the proportions of perty, discovered perhaps by chance, gave rise the different ingredients for rockets of from twelve io the idea of rendering the fire of rockets, and to thirty-six pounds.