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L E S S O N S T N C H E M I S T R Y.--No. IV. THE only tests we have hitherto employed in our chemical investigations, are hydro-sulphuric acid, and hydro-sulphate of ammonia. I.et the student now obtain the following:— 1. A solution (saturated) of prussiate of potash, also called ferrocyanide of potassium. 2. Infusion or tincture of gall nuts. 3. Hydro-sulphuret” of ammonia already prepared, by transmitting sulphuretted hydrogen gas through liquor ammonia (hartshorn), until the latter refuses to dissolve any more. 4. A solution of potash procurable at the druggist's, under the name of liquor potassae. It must be kept in a glass stoppered bottle, and not exposed to the air more than absolutely necessary. 5. A solution of carbonate of soda (washing soda). 6. A solution of carbonate of ammonia (smelling salts). 7. A solution of ammonia (hartshorn).
The preceding, in addition to hydro-sulphuric-acid gas and solution, may be regarded as the principal tests for metals. Others will occasionally come under our notice, but these are the chief.
Baving disposed of the effects developed on the solutions of manganese and zinc already employed by hydro-sulphuric-acid and hydro-sulphate of ammonia, let the student next observe the result of adding to each of these solutions respectively a solution of prussiate of potash. He will discover that this re-agent determines a white precipitate with either metal; and as a general rule it may be remembered, that yellow prussiate of potash (there is a red prussiate) determines a white precipitate with all common or calcigenous metals. To this general rule there are very important exceptions, which, however, had best be fixed in the memory as exceptions: thus, probably, even in the foregoing testing experiments the reader may observe that the precipitate yielded by prussiate of potash is tinged bluish ; if so, this result will depend upon the presence of iron, a metal which will scarcely be altogether absent from the solutions of zinc and manganese prepared by a novice in chemical operations. Let the student now proceed to test portions of zinc solution, and manganese solution, made according to preceding directions, with all the tests mentioned in the beginning of this article, and let him make notes of the results. Most of the tests will produce precipitates with both solutions, as the reader will see; and the prevailing character of the results is whiteness, or a tint approaching to whiteness. The operation of testing may be performed in conical wine-glasses, in test tubes, as they are called—instruments of the following shape, fig. 19, being glass tubes, open at one end, closed at the other, and so thin that the flame of a spirit lamp may be applied without danger of causing fracture. A third method of conducting test opera, tions, and it is a very good one, consists in the employment of flat strips of window glass, upon which a single drop of the solution to be tested is laid, and another drop of the test solution, added to it by means of a straw, or a glass rod. In this way testing operations may be conducted with great facility. Care must be taken, however, when straws are employed, never to use one straw for more than one operation.
Take next a solution of manganese, and a solution of zinc prepared as already described. Add hydro-sulphate of armmonia to either solution, and a sulphuretis of course the result. To either sulphuret add now, without necessarily decanting the fluid from which it has been thrown down, some distilled vinegar (acetic acid), and observe that all the sulphuret of manganese is solublé in this fluid, whereas all the sulphuret of zine remains undisturbed. We have already determined that, supposing zinc and manganese f to exist in one and the same * Still with greater propriety termed hydrosulphurate.
The remark applies to manganese in that kind of solution, which
results from the treatment already described, and others attended with a similar result; in other words, to protosalts of manganese.
Fig. 19. f
solution, they admit of separation by transmitting through the solution hydro-sulphuric acid, which throws down all the zinc, and leaves the manganese, which latter may be subsequently wanted, thrown down by means of hydro-sulphate of ammonia. Another method of separating the two will now readily occur to the reader. Both may be thrown down at once by hydrosulphate of ammonia, and the sulphuret of zinc redissolved by means of acetic acid. It would be undesirable at this early period of our studies to describe in greater detail the numerous analytical processes which may be had recourse to for accomplishing the separation of zinc and manganese, supposing both to exist in one solution, and supposing the manganese to be in the condition of a protosalt. Recapitulation.—1. Two solutions yield respectively precipitates with hydro-sulphate of ammonia; therefore, these solutions contain metals of the calcigenous class. 2. The precipitates are white, therefore the metals in question are either manganese or zinc. 3. One solution yields a white precipitate, with hydro-sulphurate of ammonia, though not with hydro-sulphuric acid ; therefore it must contain manganese. 4. One solution yields a precipitate both with hydro-sulphuric and hydro-sulphate of ammonia; therefore it must contain zinc. 5. Sulphuret of manganese may be separated from sulphuret of zinc, by the agency of acetic acid (distilled vinegar), in which sulphuret of zinc is insoluble. Distinction between the Moist and Dry Processes of Analysis.The moist process and the dry process are terms which, from long use, have become popularly familiar, though they by no means admit of any precise line of demarcation. There are few chemical analyses involving metals which do not require the agency of fire at some stage of their performance; again, there are few so called dry processes which do not require as adjuncts the employment of acids, and other moist chemical re-agents. As a general rule, it may be stated that the dry or igneous processes of chemistry are restricted to operations on the large scale—such, for example, as the smelting of metals. To this general rule, however, the blowpipe and its employment constitute one remarkable exception, all the processes conducted by means of this instrument being essentially Small and delicate, sometimes almost microscopic. The blowpipe is now invaluable to the chemist, although its employment in this way dates from very recent periods. Description of the Blow-pipe.--The greater number of my readers will have seen a blow-pipe, and probably will have seen it used, being employed very extensively by gas-fitters, jewellers, and some other artisans. The instrument consists in its simplest form of a bent tube, terminating in a fine jet, as represented in the accompanying diagram, fig. 20, and is
intended to cause the deflexion, by blowing through it, of a candle or a lamp-flame, as represented in fig. 21. The flame thus diverted from its upward course is necessarily limited in extent, but its heat in certain parts is very great, enabling the operator to obtain (on the small scale) most of the effects of a furnace. Generally speaking, artizans who use an instrument in their trade acquire far more dexterity in its employment than philosophers or amateurs. . So far as relates to the blow-pipe, however, there is a remarkable exception to this rule. The gas-fitter and jeweller use the blow-pipe as follows:—Taking a deep inspiration, they blow as long as the one charge of air lasts; then stopping, they inspire a fresh draught of air; atterwards they set to work again. This would never do for the chemist, whose operations demand the solution of the apparently impossible problem: to breathe and to blow uninterruptedly. It is not possible to describe by mere words how this is accomplished, farther than the description is conveyed
the lungs. } The facility with which a of good jet can be próduced and : maintained, greatly depends _y \s upon the size of the terminal
orifice, which, if too large, will require more air than can be readily supplied by the reservoir of the mouth alone. All delicately made blow-pipes are supplied with several jets of different sizes, but such refinements as these are unnecessary to the novice, who may proceed to a gas-fitter's shop, and purchase a blow-pipe for Sixpence. Having purchased it, let him now determine the distance from his eye at which vision is most perfect; which being settled, let him cit the blow-pipe to correspond. This is a somewhat important direction, and should not be neglected. so o
The Blow-pipe-jet, and its Characteristics.--If a jet of air by means of the blow-pipe be directed across the flame of a lamp or candle, just above, or a little on one side of the wick, a jet will be produced which will have, or should have, the following characteristics.
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It will be made up of a small central blue conical flame, extending from A to B, fig. 22, lying within a second and larger cone, a, b, consisting of 2 reddish-yellow scarcely perceptible halo. It is not always that the jet can be obtained so pure as here described; but this degree of purity should be always aimed at, and will sometimes even by a novice be accomplished. The most heating portion of the flame thus developed corresponds with the point B; consequently, if our object be the mere fusion of a refractory body, to the action of this point should it be exposed. This portion of the flame, moreover—indeed every part of the blue cone, possesses a deoxydizing power, that is to say, it takes away oxygen from any substance which may be exposed to it. parts oxygen, and is therefore called the oxydizing flame. The blow-pipe is not only useful to the chemist as a means of effecting the fusion and working of glass tubes, but it enables
him to operate in the dry way on all the metal or minerals.
containing them, giving rise to characteristic appearances from which the existence of any particular substance may be inferred, * Appgratus necessary to be employed in connecion with the Blowpipe.—In the first place, we require a source of flame, and this varies according to the different purposes for which the blowpipe is employed. If used for glass-blowing operations, the flame is usually such as results from the burning of a large mass of cotton wick, placed in a pan containing tallow, or a tin dish, and the blow-pipe having a very large jet, is usually worked by means of a pair of bellows. This, at least, is the arrangement usually employed by artizans in glass, such as baronycter-makers, thermometer-makers, &c. In laboratories, gas is sometimes used as the source of flame, being more convenient ; but the result is not so good. This bellows blow-pipe the student need not possess; all the glass blowing that he will require may be accomplished by the mouth blow-pipe, as will be described hereafter. For purposes óf mineral analysis, and to such we are especially directing 'our attention at present, the very best flame, according to our opinion, is that of a wax
or spermacetti candle; but the flame of a common tallow dip
wiłł answer Blost purposes.
ing from the mouth, hever from
The external faint halo, on the contrary, im
THE POPULAR EDUCATOR.
Supports.-Charcoal,—The maximum heat which the blow-pipe
jet can exert results from the contact of the blue apex with a piece of well burned charcoal.
CŞf course, some means must be
devised for holding this charcoal, and consequently there are
instruments sold under the name of charcoal-holders; they are unnecessary, however—a charcoal-holder satisfactory in every
respect may be constructed for the occasion, by taking a slip of
tin plate about six inches long by two inches wide, and bending one end twice at right angles on itself, in such a manner that is may grasp and firmly hold a piece of charcoal. When the
charcoal has been thus fixed, a little excavation should be made at the point by means of a knife, and in this excavation the substance to be operated upon should be laid, The Plation Włre-loop.–In a vast number of blow-pipe experiments, the jet is not directed upon the unmixed substance, but upon a mixture of it and another substance with which it shall form a glass on fusion, and the nature of the substance is deduced from the colour of the resulting glass. In such cases, the support most generally employed, is a loop of platimum wire. A portion of the substance to be examined being fused into the loop, together with a flux, a glass results, filling the loop as it would the frame of a window, various jo blow-pipe supports are known to chemists, but the two already described are the most important, and will answer our present purpose. . Booo-pipe examination of Zinc and Manganese.—In our moist investigations on Zing and manganese, great care was taken to obtain these metals in certain states of combination: no such Precautions will be necessary in our blow-pipe inquiries on the same. The zinc specimen may be a piece of the metal itself; the manganese specimen a portion of black, or bonoxide, otherwise called peroxide; in other words, the ordinary black manganese-ore of commerce.*, Lay a small fragment of me. tallic 3ine (about the size of a barleycorn) upon the charcoal and direct upon it the interior blow-pipe flame; remark howth.
| zinc burns; and how a white powder remains: remark too
this white powder is yellow whilst hot. Remember well these points, and compare them with the results to be obtained hereafter, by treating lead in a similar manner. Take the platinum loop, moisten it with the tongue, dip it into some powdered carbonate of soda: remove it; fuse the carbonate by directing upon it the apex of the blue come; let the fused, bead, cool; when cool moisten it with the tongue again, and apply to it a portion of powdered black oxide of manganese—but a very small portion, just as much as could be taken up on the point of a needle. Direct now the outer flame of a blow-pipe jet on the loop, and observe the result, The bead fuses, it becomes green when hot, and bluish green when cold. Repeat the experiment, substituting borax for carbonate of soda ; the bead is now violet red in the external, colourless in the internal flame. These appearances are characteristic of manganese, but the appearances lately described are characteristic of zinc ; no other metals yielding similar results under similar treatment: the student may therefore form some opinion already, concerning the value of the blow-pipe as an instrument of chemical analysis. [The following is a representation of a Glass Blower's table with double bellows worked by the foot, and blow-pipe, lamp, &c. Such an apparatus can be had in London, complete, for four guineas.] y
mortals. Atapopog, ov, different.
Agexyeta rikret isłpty. Ev Troost kat 6ptoast frox\ot story ăratpot, ev 3s grovëatop orpáygart oxyāt. "O troovrog &ravito: Kost evöstag Tovg avépatrovg Xvel. ‘Ezröw ty pilgäu. At &ro row coparoc estióvuta troXepovg kai grassic kat Haxag rapexovaty. Ev raig troXegw at apxas voflov ovätzkéc suga. Azrexégés, a Troxiral, a ragstov. Opeyegbe, w avépéc, ca)\ov Trpaësto. At&popot stow at row 6porov jvoretc. E8 #3pswg troXX& kaka. ywyveral. Kakov avópoc dupa ovnow ovk #xet. Aoč& kat TAovrog avāv ovyeasog ovk agóāAñ krijuara étotv. Öt riov ovkov capirot y\vksic stow. Apertig 658atát étau & Krygii; pova IIoxXa aarm retxm exel. Oi row agréðc rvpyot 383arot staty. Oi Tupyot Top agrét koop.og stow. -
Riches free from (Avaj) want. We have friends in eating and drinking, but not in misfortúne. In the city the king is the guardian of the laws. Obey, O young man; the magistrates. O child, strive after honourable deeds. The possession of virtue is alone sure. The city has (tò the city are) many towers. Good laws bring honour to the city. Follow nature. The soldiers fight for the deliverance (Görnpua) of the city. O citizen, avoid insurrection.
There are some nouns of the third declension which cannot be classified, and the differential points of which must therefore be given separately ; they are these
ENKXijova, &c., ii, an assembly
Quietet, ac, j, a dwelling,
Kreig, KTEvog, à, a comb.
Kreitão, locomb. XT&You, ovog, ii, a drop. A19toil, orog, an AEthiopian, Kao Top, opio, Castor, As moto, soc, j, a request, entreats. A trigrog, or, unfaithful, inadmissible, E make straight, I direct. - “.
AExoplat, I receive.
THE POPULAR EDUCATOR.
You have seen how the growth, the decay, and the successions of vegetable life, have contributed to the formation of the crust of the earth. You are now invited to examine the contributions which animal life has made to produce some of the rocks on our globe. There are animal organisms which are really the spontaneous and hard-working architects of rocks and mountains. This lesson will not refer to those which are piling up rocky masses by their direct agency, but to those whose remains contribute to the formation of soil, plains, and hills. We will begin with the contributions of the smallest and the minutest animal existences, the majority of which can be detected only by powerful microscopes, and with those of some others that are just visible to the naked eye. These diminutive organisms are called animalculae, or little live things. They are sometimes called Infusoria, on the ground that they are discovered in all vegetable infusions, in the waters of the seas, rivers, lakes, ponds, and puddles, and in liquids used for domestic purposes. These agents cannot be seen with the naked eye. They helong, as Dr. Mantell has said, to an “invisible world.” They make their invisible agency to be known by their works. The Sacred Scriptures teach us that “the things which are seen were not made of things which do appear.” This is a primary article in the creed of every intelligent geologist. He applies it to account for the creation of all the worlds of matter as the results of the power and skill with which the Supreme Artist combines invisible gases, and says “let the dry land appear.” . The same article can be applied to the large and innumerable rocks and hills which have been produced, not of course by one immediate fiat, but by the slow and invisible agents which He had created and appointed to execute
the work. The forms, the structure, and the instincts of these animalculites belong to the science of Palaeontology. Our concern now is, to exhibit them as contributing agents to the formation of the earth’s crust. The science of chemistry, and the microscope, have shown that some extensive rocks and high mountains are nothing, but enormous masses of animalculite relics, or immense sepulchres in which their remains are entombed. So extensively and so abundantly are their relics found in soils and rocks, that you may well ask, with the poet You:NG, “ where is the dust that has not been alive P” The composition of several rocks show that the different tribes of these animalculites were countless, that various kinds of them appeared
on the earth successively, that they lived and worked here for indefinite periods, and then vanished, and made way for other kindred generations. The most distinguished student of animalculites is EHRENBERG of Berlin, who is the Lord Ross E of the microscope. These tiny animals exist in ten million times ten millions, and millions of millions, and are found living in all water and liquids. Wherever you see a spot of yellow or ochreous scum in a pond, or ditch, or any stagnant water, that scum consists of an aggregation of hosts of animalculae. The living thing itself that is called an animalculite, or an infusorian, is a soft, juicy, fleshy, or mucous substance, that, for the most part, lives in a case which forms its house and home. This case is sometimes called its shield and sometimes its shell; and by technical writers it is called the carapace. Some, however, exist without such cases, but are naked and have a flexible skin. The cases or shields of animalculites differ in different species. In one class, the shields are calcareous or limy; in others siliceous or flinty; in others, ferruginous or irony. Their forms and shapes are innumerable, but frequently of great beauty and symmetry. The Xanthidia are a hollow globe of flinty matter. The Pyxidiculae have a case like a saucer which is filled with their body. The Bacillariae look like a dozen cards placed in zigzag row, one touching the other at a point. The Naviculae have a bivalve shell with six openings. The Gaillonellae have a bivalve case, but of a cylindrical and half globular form. You will find the rich and beautiful variety of their shapes well illustrated in Dr. Mantell’s “Medals of Creation,” and especially in his “Invisible World. It is these shields or cases of the animalculite, and not the animalculites themselves, that claim the attention of the geologist, for it is these shields that he discovers mineralised, and which, in a fossil state, constitutes vast rocks in the crust of the earth. Ehrenberg has found them in flint, in opal, in chalk, and in many other rocks. They are found in vast profusion in rocks of different periods—such as the tertiary series, and in the chalky and other secondary deposits. Fossil animalculites are those which had shields; for the races that were naked and had a flexible skin had nothing enduring in their structure. Our lesson will embrace not only the fossils which belong strictly to the infusoria, but also other minute organisms with which they are associated. One class of these are called Polythalamia, because their shells have many chambers in them, and are not like that of the snail, which has only one. The other are called Foraminifera, because their cases or shells are covered with pores, or because the different chambers of their shell are connected by a pore, and not by a siphuncle that runs through each.
ANIMALCULITES IN SOILS AND SANDS.
At the bottom of many swamps and peat bogs, whether resting on modern soils or on ancient rocks, there are generally found layers of white, marly, or flinty paste or clay. This paste or clay is made up entirely of the shields of infusoria. They are found in abundance under the bogs of Ireland, in Lough Island, near Newcastle, and in many parts of North America.
This statement refers to peat bogs of the present age; but when we examine the deposits of the tertiary period, the animalculite relics far surpass, both in multiplicity of forms and in extent of distribution, any infusorial strata of modern times. And even the profusion which is found in the tertiaries of England is not to be compared with those of the continent, such as France and Germany, and also those of North America. The rocks of the Paris basin abound with marine sands. These sands are so full of microscopic animalculites, that a cubic inch of them—that is, a mass cut and squared like a dice an inch each way—would contain sixty thousand Foraminifera and Infusoria. This is particularly the case with the sands brought from Grignon in that neighbourhood. In the district of Bilin, in Northern Germany, there is a rock called “polishing slate.” . The rock is of considerable extent, and is fourteen feet in thickness. It consists entirely of the flinty shields of Gaillonellae. These shells are so minute, that a cubic inch of the slate contains forty-one thousand millions, 41,000,000,000 of animalculites. in Lapland there is a rock of fossil flour, which is called Bergmehl, or mountwin meal. When bread is scarce,
the inhabitants mingle this fossil meas with the four of corn, or with meal made of the bark of trees, ground for food. 'I lis Bergmehl, or fossil flour, is one mass of animalculites. The same kind of rock is found at San Fioro in Tuscany. In the neighbourhood of Eyra, in Bohemia, there is dug up a fine white earth, which lies about three feet under the surface. When this earth is dry, it has all the appearance of pure magnesia; but when it is examined by the microscope, it is seen to be formed entirely of an elegant species of infusorial shełks called Campilodisca. In North America, one of the most celebrated places for infusorial rocks, is a district that lies between the cities of Richmond and Petersburg in Virginia. The city of Richmond is built on a stratum of flinty marls, having a thickness of more than twenty feet, extending as far as Petersburg, and spreading out into sterile tracts along the sides of the hills. These formations are supposed to belong to the older tertiaries, the meiocene or the eocene. The whole of these deep and extensive marls are composed of infusorial remains. “When,” says Dr. Mantell, in “Medals of Creation,” p. 225, “a few grains of this marl are prepared, and mounted on a glass, almost all their varieties will be manifest, so largely is this earth composed of the skeletons of animalcules: in fact, very few inorganic particles are intermixed with the organisms. The merest pellicle or stain, left by the evaporation of a drop of water in which some of the marl has been mixed, teems with the most beautiful structures.”
ANIMALCULITES IN CHALK.
Few of the revelations of geology have been more astonishing than the discovery, that a large proportion of the purest white chalk consists of minute chambered shells and microscopic corals, all of which are of the most complete and exquisite structure. . If you scrape or brush a piece of chalk in water, and examine a small patch of the sediment by a microscope, you will see that it consists of a vast abundance of the cases or shells of Polythalamia, Foraminifera, and Polyparia. Nevertheless, even these microscopic creatures must appear colossal when you think that these animalculae live upon infusoria more diminutive than themselves. A cubic inch of white chalk contains, according to Ehrenberg, more than one million of well-preserved shells of animalculites.
This thought is almost overwhelming, when you consider, in connection with it, the vast extent and the great depth of the chalk formation on the surface of the globe. All the Chalk Downs of England, and the cretaceous rocks of the earth, are only an accumulation of exceedingly minute organisms, which are so closely packed together, that a piece of soft chalk, that you use in making a mark or drawing a line, has half its bulk formed by fossil bodies. This is the case with our English chalk; but in the chalk of the South of Europe, the profusion of animalculite remains is in much greater proportion.
There is, of course, in every mass of chalk, a quantity of matter where no animalculite organisms appear in the field of the microscope. This inorganic matter does not owe its ori. gin to a precipitation of lime that was previously held in solusion by the water, but it is the result of the attrition and disintegration of the infusiorial organisms into a more pulverized mass of calcareous particles, which have been afterwards reunited by crystallisation.
The upper part of the chalk formation abounds in nodules of flint. Geology has lately shown that these modules of flints have originated in an accumulation of the pulverised and ground particles which have been derived from the siliceous or flunty shields of animalculites. The late Dr. Mantell distinguished him.self much by his researches, chemical and geological, among these infusoria. He says that the most abundant microscopical forms of animalculae discovered in the chalk and flints of England are two kinds of Polythalamia, called the Rotalia and Textularia. Associated with these are immense numbers of the class called Foraminifera.
These animalculite families are found to be most extensively
distributed in the rocks of every part of the globe. In the East, they have been discovered in the Mount of Olives near Jerusalem, in the Plains of Damascus, in the Hills of Anulibanus, and in the rocks about Beyrout. In the South, it has been ascertained that a large Proportion of the sund of ule labyan desert of Africa consists of microscopie shells. In North