LESSONS IN CHEMISTRY.--No. IV. THE only tests we have hitherto employed in our chemical investigations, are hydro-sulphuric acid, and hydro-sulphate of ammonia. Let 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 potassa. 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.

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 zine redissolved by means of acetic acid.

to describe in greater detail the numerous analytical processes It would be undesirable at this early period of our studies 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 aciù ; 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.

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

Having 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 Distinction between the Moist and Dry Processes of Analysis.re-agent determines a white precipitate with either metal; and The moist process and the dry process are terms which, as a general rule it may be remembered, that yellow prussiate from long use, have become popularly familiar, though_they of potash (there is a red prussiate) determines a white preci- by no means admit of any precise line of demarcation. There pitate with all common or calcigenous metals. To this general are few chemical analyses involving metals which do not rule there are very important exceptions, which, however, had require the agency of fire at some stage of their performance; best be fixed in the memory as exceptions: thus, probably, again, there are few so called dry processes which do not even in the foregoing testing experiments the require as adjuncts the employment of acids, and other moist Fig. 19. reader may observe that the precipitate yielded chemical re-agents. As a general rule, it may be stated that by prussiate of potash is tinged bluish; if so, the dry or igneous processes of chemistry are restricted to this result will depend upon the presence of operations on the large scale-such, for example, as the smeltiron, a metal which will scarcely be altogethering of metals. To this general rule, however, the blowpipe and its absent from the solutions of zinc and man- employment constitute one remarkable exception, all the proganese prepared by a novice in chemical cesses conducted by means of this instrument being essentially operations. Let the student now proceed to small and delicate, sometimes almost microscopic. The blowtest portions of zinc solution, and manga-pipe is now invaluable to the chemist, although its employnese solution, made according to preceding ment in this way dates from very recent periods. 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 operations, 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 am monia to either solution, and a sulphuret is 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 soluble in this fluid, whereas all the sulphuret of zine remains undisturbed. We have already determined that, supposing zinc and manganese † 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. 20.

The

intended to cause the deflexion, by blowing through it, of
a candle or a lamp-flame, as represented in fig. 21.
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

trade acquire far more dexterity in its employment than Generally speaking, artizans who use an instrument in their 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; afterwards 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 in a general direction, to consider the cheeks as a pair of

Fig. 21.

double bellows: always blow-charcoal has been thus fixed, a little excavation should be made
ing from the mouth, never from at the point by means of a knife, and in this excavation the
the lungs.
substance to be operated upon should be laid.

The facility with which a good jet can be produced and maintained, greatly depends 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 cut the blow-pipe to correspond. This is a somewhat important direction, and should not be neglected.

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. Fig. 22.

R

The Platinum Wire-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 platinum 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 other blow-pipe supports are known to chemists, but the two already described are the most important, and will answer our present purpose.

Blow-pipe examination of Zinc and Manganese.-In our moist investigations on zinc 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 binoxide, otherwise called peroxide; in other words, the ordinary black manganese-ore of commerce.* Lay a small fragment of metallic zinc (about the size of a barleycorn) upon the charcoal, and direct upon it the interior blow-pipe flame; remark how the 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.

It will be made up of a smail central blue conical flame, ex- into some powdered carbonate of soda: remove it: fuse the Take the platinum loop, moisten it with the tongue, dip it tending from A to B. fix. 22, lying within a second and larger carbonate by directing upon it the apex of the blue cone: let cone, a, b, consisting of a reddish-yellow scarcely perceptible halo. It is not always that the jet can be obtained so pure as here the fused bead cool: when cool moisten it with the tongue described; but this degree of purity should be always aimed at, manganese-but a very small portion, just as much as could be again, and apply to it a portion of powdered black oxide of most heating portion of the flame thus developed corresponds of a blow-pipe jet on the loop, and observe the result. The and will sometimes even by a novice be accomplished. The taken up on the point of a needle. Direct now the outer flame with the point B; consequently, if our object be the mere fusion bead fuses, it becomes green when hot, and bluish green when of a refractory body, to the action of this point should it be cold. Repeat the experiment, substituting borax for carbonate exposed. This portion of the flame, moreover-indeed every of soda: the bead is now violet red in the external, colourless in part of the blue cone, possesses a deoxydizing power, that is to the internal flame. These appearances are characteristic of say, it takes away oxygen from any substance which may be exposed to it. The external faint halo, on the contrary, im-istic of zinc; no other metals yielding similar results under manganese, but the appearances lately described are characterparts oxygen, and is therefore called the oxydizing flame. similar treatment: the student may therefore form some 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 opinion already, concerning the value of the blow-pipe as all instrument of chemical analysis. 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.

Apparatus necessary to be employed in connexion 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 barometer-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 he described hereafter. For purposes of mineral analysis, and to such we are especially directing our attention at prescat, the very best flame, according to our opinion, is that of a wax or sperniacetti candle; but the flame of a common tallow dip will answer most purposes.

Supports.—Charcoal. The maximum heat which the blow-pipc jet can exert results from the contact of the blue apex with o piece of well burned charcoal. Of 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 u may grasp and firmly hold a piece of charcoal. When the

with double bellows worked by the foot, and blow-pipe, lamp, [The following is a representation of a Glass Blower's table, &c. Such an apparatus can be had in London, complete, for four guineas.]

Some substantives in is, as well as the adjectives in ις, 4, 5. uc, - as ίδρις, ιδρι, skilful, have the regular indexion, without ony change of the radical vowel, e.g. o, ý, Toρris, a calf or heifer; δ, ή, οἷς, a sheep ; also (in the singular) ή εγχελυς, an cel.

EXERCISES.-GREEK-ENGLISH.

Αἱ γυναίκες τῳ κοσμῳ χαίρουσιν. Οἱ Ἕλληνες σεβονται Δια και Ποσειδων και Απολλω και αλλους θεους. Ταῖς γυναιξιν ἡ αιδως πρεπει. Οἱ κυνες τον οικον φυλαττουσιν. Ὁ κυβερνητης την ναυν ιθυνει. Αἱ σταγονες του ύδατος πετραν κοιλαινουσιν Της γυναικός εστι τον οικον φυλάττειν. Γυναικος εσθλης εστι σωζειν οικίαν. Αει εν πιπτουσι Διος κυβοι. Οἱ κυνες τοις ανθρωποις ωφελειαν και ἡδονην παρεχουσιν. Αἱ των μαρτύρων μαρτυριά πολλακις απιστοι εισιν. Ιστοι γυναικων εργα και ουκ εκκλησιαι (sc. εισιν). Κομιζε, ω παι, την της κιστης κλεῖν, Ω Ζευ, δεχον την του ατυχους δεησιν. Καστωρ και Πολυδευκης των νέων σωτηρες ησαν. Γυναικι παση κοσμον ἡ σιγη φερει. Οι Αιθίοπες την τριχα μελαιναν εχουσιν. σωζε την Τῳ κτενι τας τρίχας κτενιζομεν. Αιακος τας Αίδου κλεῖς φυλαττει.

οικιαν.

ENGLISH-GREEK.

Ω

γυναι,

Ornament becomes a woman. Ornament becomes women. It is the business of women to guard the house. They bring the keys of the house. The keys of the house are brought to the mother. The Athenians had (to the Athenians were) many ships. Jupiter had (to Jupiter were) many temples. The The fish emerge out of the water. steersman guides the ship. The ship is guided by the steersman, You worship Jupiter and Apollo.

ποαον

πραου
πρα

There are also some

Irregular Adjectives,

the forms of which I must set before you, as πραος, πραεία, πραον, soft; πολυς, πολλή, πολυ, much, pl. many; μεγας, μεγαλη, μεγα, great; as follows:

S. Ν.

πραος

πραεία

G.

πραου

πραείας

D.

πραγ

πραεία

Α.

ON ANIMALCULITE CONTRIBUTIONS TO THE FORMATION
OF ROCKS.

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 contri-
butions 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 moun-
tains. 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 formnation 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 animalculæ, 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 belong, 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 Palæontology. 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 YouNG, "where is the dust that has not been alive?" The composition of several rocks show that the different tribes of these ani

Πολυν οινον πινειν κακον εστιν. Οἱ βασιλεις μεγαλας προσο- malculites 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 Rosse 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 animalculæ,

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 Pyxidiculæ have a case like a saucer which is filled with their body. The Bacillariæ look like a dozen cards placed in zigzag row, one touching the other at a point. The Naviculæ have a bivalve shell with six openings. The Gaillonellæ 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.

The

the inhabitants mingle this fossil meal with the flour of corn,
or with meal made of the bark of trees, ground for food. This
Bergmehl, or fossil flour, is one mass of animalculites.
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 mag-
nesia; but when it is examined by the microscope, it is seen
to be formed entirely of an elegant species of infusorial shells
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 Rich-
mond 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 animalculæ 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 protusion of animalculite remains is in much greater proportion.

There is, of course, in every mass of chalk, a quantity of matter where no animalculite organisins appear in the field of the microscope. This inorganic matter does not owe its origin 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.

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 The upper part of the chalk formation abounds in nodules of in extent of distribution, any infusorial strata of modern times. fiint. Geology has lately shown that these nodules of flints have And even the profusion which is found in the tertiaries of originated in an accumulation of the pulverised and ground parEngland is not to be compared with those of the continent, ticles which have been derived from the siliceous or flinty shields such as France and Germany, and also those of North America, of animalculites. The late Dr. Mantell distinguished hin.self The rocks of the Paris basin abound with marine sands. These much by his researches, chemical and geological, among these sands are so full of microscopic animalculites, that a cubic inch infusoria. He says that the most abundant microscopical of them—that is, a mass cut and squared like a dice an inch forms of animalcula discovered in the chalk and flints of each way-would contain sixty thousand Foraminifera and England are two kinds of Polythalamia, called the Rotalia and Infusoria. Associated with these are immense numbers This is particularly the case with the sands Texitularia. brought from Grignon in that neighbourhood. In the district of the class called Foraminifera. of Bilin, in Northern Germany, there is a rock cailed" "polishThese animalculite families are found to be most extensively ing slate." The rock is of considerable extent, and is fourteen distributed in the rocks of every part of the globe. In the feet in thickness. It consists entirely of the flinty shields of East, they have been discovered in the Mount of Onves near Gaillonellæ. These shells are so minute, that a cubic inch of Jerusalem, in the Plains of Damascus, in the Hills of Anulithe slate contains forty-one thousand millions, 41,000,000,000 of banus, and in the rocks about Beyrout. In the South, it has animalculites. In Lapland there is a rock of fossil flour, which been ascertained that a large proportion of the sand of the Ladis called Bergmehl, or mountain meal. When bread is scarce, yan dezert of Africa consists of microscopic shells. In North