When the aspirator is empty, the tubes are again weighed, and thus from the increase of weight we learn the quantity of moisture and carbonic acid gas which were in the volume of air in the aspirator. The moisture in the air varies immensely. The proportion of carbonic acid is generally about of the whole volume of the atmosphere. Traces of ammonia and sulphuretted hydrogen are found near towns especially; and nitric acid is frequently present after a thunder-storm. The average composition of the atmosphere is Oxygen Carbonic acid. Aqueous vapour Nitric acid Ammonia Carburetted hydrogen In towns (Sulphuretted hydrogen Sulphurous acid 20.61 77.95 04 1.40 traces traces The liquid thus obtained fumes in the air, and ought to be colourless, but is usually tinted yellow by the presence of the next lower oxide-the yellow gas-nitrous acid. It easily parts with some of its oxygen, and is therefore a good" oxidising agent." If, for instance, a piece of copper be thrown into a little nitric acid, violent action shortly commences, especially if the liquid be warmed; dense red fumes are given off, and the copper becomes cupric nitrate, blue vitriol (Cu2NO,); by diluting the solution and slowly evaporating, the blue crystals of the salt may be obtained. Its readiness to part with its oxygen is also shown by dropping the acid into hot, finely-divided charcoal, which begins to burn vividly. If the nitric acid be required in a very powerful form, some sulphuric acid is added, which deprives the nitric acid of its water. Oil of turpentine bursts into flame when such a mixture is poured into it. All the metals, except gold and The physical properties of the atmosphere not coming within platinum, are attacked by this acid. Thus the actual domain of chemistry, we pass on to Nitrous oxide, or Laughing Gas. The regularity of their formation offers the best of examples of the law of "multiple combination." It will be seen that the compounds are formed by the addition of an atom of oxygen, the quantity of nitrogen remaining the same. Hence the increase of the atomic weights will be by the addition of 16; and as atoms are indivisible, therefore there can be no addition to the weight, save in a multiple of 16. The law of which this is an example, is an evident deduction from Dalton's atomic theory, which has been already explained. It is known by the name of "the law of chemical combination in multiple proportion." Nitrogen only combines with oxygen under peculiar circumstances. Whenever an electric spark passes through the atmosphere, their combination is effected. Thus, after a flash of lightning, nitric acid is always found in the air. We also find this compound is frequently formed during the putrefaction of animal matter, and it occasionally happens that some of the lower oxides of nitrogen are also produced at the same time. Fig. 31. we have a means of deciding between real gold and a mere electrolytic gilding. On the former a drop of the acid remains unchanged, whilst in the latter case it becomes green. To test for the presence of Nitric Acid.-If any body be supposed to contain this acid, whether in a free or in a combined state, get the substance into solution, add an equal quantity of sulphuric acid, which will set the nitric acid free, and carefully add a concentrated solution of iron sulphate (green vitriol). If any nitric acid be present, a black ring will be formed at the place where the two liquids meet. The anhydrous acid (N,O,) may be obtained by a method prosilver nitrate, the action beingposed by Natterer. Dry chlorine gas is passed over crystals of 2AgNO, +2C1 = N,O, + 0 + 2AgCI. The silver chloride remains in the bulb, the oxygen escapes, and the anhydrous nitric oxide condenses in a U tube, which is placed in ice, and which is joined to the bulb containing the silver salt. The substance collects as a white crystalline solid. It must be kept in a sealed tube, or it abstracts water from the air, and becomes liquid nitric acid. Hence it is only a chemical curiosity, and of no practical use. In concluding this lesson we add tests tor ascertaining the purity of commercial nitric acid, for every care ought to be taken that laboratory chemicals are pure. Since the process for obtaining nitric acid in large quantities is carried on in a cast TUSSUU iron retort, and at a high temperature, the acid generally contains sulphuric and hydrochloric acids. To discover the presence of the first substance, take some of the suspected acid, dilute it with four times its volume of water, and add a little barium chloride. The insoluble barium sulphate will be formed if the slightest trace of sulphuric acid be present, and it will exhibit itself in a white precipitate. In testing for hydrochloric acid, it is not necessary to dilute the nitric acid, but add a few drops of a solution of silver nitrate, and if any hydrochloric acid be present, then there will be a white curdy precipitate of silver chloride. The two reactions are thus expressed : H,SO. + BaCl, = BaSO,+ 2HCI, and HCl + AgNO, AgCl + HNO,. LESSONS IN BOTANY.-XXII. SECTION XLII. RUBIACEAE, OR GALIACEÆ. Characteristics:-Calyx superior, adherent to the ovary; corolla monopetalous, epigynous; stamens inserted upon the corolla; ovary inferior, two or more celled, containing one or many seeds; seed dicotyledonous, albuminous; leaves stipulate. This family, one of the most important in the whole vegetable kingdom, derives its name from the Rubia, or madder, one of its principal genera. The name Galiaceae, which is also applied to this family, is derived from the Galium, or ladies' bedetraw. The Rubiacee are either trees or shrubs, sometimes herbs, especially those indigenous to Europe. The leaves are opposite, or verticillate, and furnished with stipules. Their stipules are subject to variations. Usually they are what is called interpetiolar, the adjacent stipules of different opposite leaves becoming fused into one organ, but sometimes they constitute, bodies altogether resembling ordinary leaves, and verticillate, then to be distinguished from real leaves thus arranged by the absence of axillary buds. The flowers are complete, or very rarely incomplete by abortion; ordinarily regular; their disposition is various, either in the form of cyme, or paaicle, or capitulum. The calyx is adherent by its tube to the ovary; its limb is tubular or truncate. The corolla inserted on the tube of the calyx is infundibuliform, campanulate, or in few cases rotate: its limb is four to six partite, the parts being ordinarily equal to each other; valvular or sometimes gyrate' in æstivation. Stamens inserted on the tube of the corolla, their number almost invariably equal to that of the divisions with which they are alternate; anthers introrse; the ovary crowned by a fleshy disc, more or less prominent, generally formed of two carpels, constitating two cells, one, two, or many ovulate. The ovules, reflected or carved, are ascending or erect; style simple; stigmata bifid usually, bit varying according to the numver of the carpels. The fruit of plants of the madder family may be a capsule, a berry, or a drupe. The Rubiace may be distinguished from all other natural orders by their inferior ovary, their cultivated it largely in the country about Caen, and exported large quantities. It is a curious circumstance in reference to the colouring matter of madder, that it penetrates the whole organism of animals which eat it, and dyes their bones. Many other species of the genus Rubia furnish a red colouring matter; amongst these we have the Rubia peregrina, Rubia lucida, Rubia angustifobia, Rubia longifolia. Many foreign species are also tinctorial. India possesses the Rubia Munjista, Chili the Rubia Relboun, the West Indies the Rubia Guadalupensis and Rubia hypocarpa. SECTION XLIII-CINCHONACEÆ. This important natural order contains a great number of valuable medicinal plants, of the principal of which-namely, those which supply us with the Cinchona bark-we shall speak in a future lesson. The order by many botanists is considered as forming a sub-order of the order Rubiacea. 182. BRANCH OF COFFEE TREE. monopetalous corolla, and their opposite simple leaves, with interpetiolar stipules. They are allied by many strong points of resemblance to the Caprifoliaceae; but they also present many analogies to other natural orders, a circumstance not to be marvelled a considering how numerous is this family. Madder (Rubia tinctorum) is a perennial vegetable, having a long straggling root, and square knotty stems, upon the angles of which grow coarse bristly hairs; the leaves are verticillate; the flower is small, and of a greenish-yellow colour; the berry is black. Madder is indigenous in the eastern and central states of Europe, but its cultivation is now successfully prosecuted in many districts of the western countries, being of Treat atility in dyeing. Chemists have succeeded in extracting the colouring matter in tho condition of purity, and have denominated it a'izarine, the name being derived from the term izari or alizari, by which madder is known in the Levant. Alizarine is volatile, hence it may be obtained by sublimation. The dyeing properties of madder have been known from times of very great antiquity. Strabo relates that he saw this plant cultivated by the Gauls of Aquitania, who called it carancia, whence is derived the French word garance for madder. During the Middle Ages the Normans VOL. II. Characteristics :-Leaves simple, entire, opposite, with stipules between the foot-stalks; calyx superior, adherent to ovary; corolla monopetalous, tubular and regular, with segments equal in number, to the segments of the calyx when there are divisions in the calyx; stamens rising from the corolla in alternation with its segments; ovary inferior and commonly two-celled; style simple; fruit pulpy in some, dry in others, sometimes splitting into two halves. Ipecacuanha (Cephalis ipecacuanha) is an exceedingly valuable member of the natural order Cinchonacea. It is a little shrub which inhabits the forests of Brazil. Its root is about the size of a goosequill, yellow in colour, and furnished with a grey bark disposed in the form of rings very close together. The stem is one or two feet high; the leaves disposed in pairs. The active properties of ipecacuanha reside in the bark of the root, which furnishes a valuable medicine which acts as a purgative and emetic then administered in large doses, and as an expectorant in small doses. Perhaps the most important indi vidual of the Cinchona tribe is the coffee plant. Coffee is the produce of an evergreen shrub, a native of Abyssinia and Arabia. The fruit is a berry about the size of a cherry, covered with a pulp sweet in taste and not very thick. Inside this pulp are two seeds, separated from each other by a parchment-like membrane. These seeds are the well-known coffee. The coffee seed has been frequently analysed; chemists have found in it several oily gums and albuminous matters, but the valuable principle is crystalline, and denominated caffeine. Every person knows that coffee is rendered fit for culinary purposes by the process of roasting, but the precise agency of this roasting process is not understood. It is supposed that it was only in the fifteenth century that coffee was transported from Abyssinia to Arabia Felix. But if Arabia be not the native land of coffee, it is at least its most prosperous adopted home. Nowhere does the plant flourish better, nowhere is the resulting coffee so delicious in flavour, especially that grown in the country of Yemen, in the environs of Mocha. The Orientals, it is well known, first introduced the use of coffee into Europe; but when they, the Orientals, first became acquainted with the beverage is still uncertain. An Arabian author of the fifteenth century, named Shehabeddin, states that the Mufti of Aden, in the ninth century, was the first who used coffee as a beverage; but it is certain that at this period 44 An the use of the infusion was known in Persia. According to vulgar | was right, after all, though not after the fashion she intended; tradition, the discovery of coffee is due to the mollah Chadelly, coffee has passed away and been forgotten, "like Racine!" whose memory is held in reverence by all true Mussulmans. About the same time it was that coffee first came into favour at This pious man, afflicted with sorrow at the thought that he Vienna. The Turks, driven from before the walls of that city by could not keep awake for the performance of his nocturnal devo- Sobieski, left their camp in the hands of the conqueror. In this tions, besought Mahomet to indicate some means by which sleep camp there was abundance of coffee, and a retinue of slaves might be chased away. Mahomet, touched with pity, as well whose office was to prepare it. Coffee had already been introhe might, seeing that his own honour was concerned, so brought duced amongst the Londoners in the following manner. matters about that a herdsman came to acquaint mollah Chadelly English merchant named Edwards, returning from Smyrna, of the curions fact that his (the herdsman's) goats could not go brought with him a Greek servant, Pasquet by name, who opened to sleep after they had partaken of coffee berries, but kept a coffee-shop in Newman's Court, Cornhill, in 1652. Other frisking about all night long. The mollah, taking the hint, at coffee-shops speedily arose, but Cromwell, then in power, set once prepared a good strong dose of coffee. He drank it, and himself against them and closed them, fearing lest they might was delighted beyond measure at the result. Not a wink of injure the taverns. Another account says that the first coffeesleep did he get; delicious sensations crowded on his brain; shop in England was opened by a Jew named Jacobs, at Oxford, and his midnight devotions were so fervent that he at once in 1650. communicated the precious secret to some dervises, who, imitating his example, beleaguered the prophet, now in the seventh heaven of bliss, with unceasing prayers. According to another tale, the discovery was made by the prior of a convent of Maronites, who, on receiving the report of a camel-driver to the effect that his beasts could get no sleep after having browsed on the coffee plant, at once bethought himself what a good thing coffee would be for his monks, who, like the mollah Chadelly, appear to have been torpid, sleepy fellows, and had acquired the disreputable habit-not quite obsolete now-of going to sleep in church. The practice, we are told, was quite successful. But coffee, like many other good things, had its enemies, and strange to say, the very Mohammedan priests who were amongst the first to patronise it became its most rancorous foes. The fact was this. So generally was coffee approved of by the Arabian populace, that people, instead of going to the mosque, spent their days in coffee-shops; and as there does not appear to have been any act of parliament to enforce the closing of coffee-houses during church-or rather mosque-hours, the priests had an audience of empty benches. Forthwith the mollahs anathematised the seductive berry and those who used it. Coffee, they said, was as bad as wine and spirituous liquors, if not worse. Its employment was interdicted throughout every part of the Turkish empire. Religious anathemas, however, being insufficient to check the growing evil, at length an appeal was made to physical force. "In the year of the Hegira 915" (A.D. 1538), says an Arabian historian, "whilst large numbers were assembled in the month of Rhamadan, employed in drinking coffee, the captain of the guard surprised them, hunted them ignominiously from the shops, locked them up all night in the pasha's house, and the next morning administered to each individual, by way of salutary admonition, seventeen stripes." Persecution, as usual, accomplished a result the very opposite to that intended. Coffee speedily became universally popular. In the first half of the seventeenth century there numbered in Cairo no less than 2,000 coffee-shops. At the present time coffee is amongst Eastern Mussulmans one of the first necessaries of life. When a Turk adds a new wife to his associated beauties, he formally contracts with her friends that she is always to have plenty of coffee. If certain modern accounts, however, are to be trusted, Turkish ladies have got into the habit of drinking brandy. According to Mahomet, they have no souls to lose; hence they may drink spirituous liquors with impunity. Before the seventeenth century coffee was scarcely known in France, even by name. At length certain travellers returning from the East brought a little coffee with them for their own private use. In the year 1647, Thevenot invited some friends to a party, and gave them coffee to drink; but he had been preceded by a Levantine, who, three years before, established at Paris a coffee-shop; his speculation, however, did not succeed. It was in the beau monde that coffee first became popularised. The Turkish ambassador at the French Court, Soliman Aga, was in the habit of offering coffee, after the manner of his country, to those who attended his levees. The ladies of the French Court no sooner heard of this custom than they expressed their desire of tasting the seductive liquor; whereupon the Turk, being a polite man, as all Turks are, invited the ladies to his house, and gave them coffee to their hearts' content. Madame de Sevignó was opposed to this fashion; she did not approve of coffee; said it was only a short-lived taste; that it would pass away and be forgotten, like Racine. Well, the lady All the supplies of coffee imported for a long time into Europe were obtained from Arabia. It was brought by way of Alexandria and the Levant; but the pashas of Egypt and Syria imposed enormous taxes upon it. Europeans then began to obtain it by the channel of the Red Sea. Holland took the lead in this commerce; next followed France, and, lastly, England. In 1699, the Dutch, under the direction of Van Horne, first president of the Dutch East Indian colonies, having procured certain coffee plants, sent them to Batavia, where they flourished well. The French next introduced coffee into Martinique; and we, following their example, planted the coffee shrub in many of our tropical colonies. LESSONS IN LATIN.-XXII. We have previously seen that a long (a) characterises the first and are of later origin. For Frequently, in order to understand a formation, you will require to know how letters are related one to another. instance, the supine of lego is lectum. Here the g seems to have disappeared. It is, however, represented by the c. Thus, instead of the hard legtum, we have lectum. In reri, the perfect of rego, the g seems to have disappeared. But it has its representative in the c or k in xi; thus rexi, if written according to the sound (phonetically), would be regsi or recsi (reksi). The sibilant (s) is also introduced for the sake of euphony. To pursue this subject in detail would require more space than we have to give. It must suffice to have put you in the right direction. When your ear, by constant practice, is accustomed to the combinations of letters which the Latins were fond of, you will have received a great assistance towards correctly forming the several parts for yourself. Let us now take up the chief parts separately, and the present From these are formedstems, am(a), doce, leg, and audi. 1. Present subjunctive active with the pres. ind, and subj, passive. 2. Imperf. ind. act. and pass. 3. Future ind, act. and pass. 4. Participle pres. act.; fut. pass. and the gerund. Accordingly we have Am 1. Am-em. Am-or. Am-er. Am-andum. The future of the third conjugation has the termination am, and that of the fourth ar, instead of bo. The subjunctive passive of the third and fourth conjugations ends in ar instead of er. I have here confined myself to amo and its parts for the sake of simplicity. It will be a good exercise for you to draw out the forms of the three other conjugations according to these examples. The forms of the verb not mentioned above are made by combination with the participles and parts of the verb esse, to be. Thus the perfect, pluperfect, and second future passive are formed by joining to the perfect passive participle sum, sim, eram, essem, ero, or fuero; for example, amatus sum, amatus essem, amatus ero, etc. The infinitive future active is formed by adding esse to the participle future active, as amaturum esse. The infinitive future passive is formed by joining iri with the participle perfect passive, as amatum iri. GENERAL VIEW OF THE TENSE-ENDINGS, INDICATIVE AND SUBJUNCTIVE, OF THE FOUR CONJUGATIONS. In the third person plural indicative active and passive the connecting vowel u is found after i and u, as audi(u)nt, audi(u)ntur, so acu(u)nt. In the future active and passive of the third and fourth conjugations the tense-stem, as in the subjunctive present, ends in am, ar; as Legam, Active. Legur, Passive. Audiam, Active. Audiar, Passive. But the a of the first person is changed into e in the rest; as Active. Passive. Active. Passive. Sing. 1. Legam. Legar. Audiam. Audiar. 2. Leges. Legeris. Audies. Audieris. 3. The course of instruction through which you have now gonewill require constant repetition. When you have made yourself master of the forms which ensue, by imprinting them on your memory, you will do well to go over and over again these inWith diligence combined with observation, you will then make yourself familiar with the Latin verb, not as a mere matter of rote, but understandingly; knowing well how the parts are formed one from the other, and how they are all connected with the common stem. I advise you, however, to question yourself very narrowly, and again and again, before you attempt to pass to the conjugation-forms which I am about to supply you with, though you will do well to refer to these forms for aid in understanding my remarks, and seeing their application. GENERAL VIEW OF THE TENSE AND PERSON-ENDINGS OF ALL. FOUR CONJUGATIONS OF THE ACTIVE VOICE. LESSONS IN BOOKKEEPING.-V. THE DAY-BOOK, JOURNAL, ETC. THE next book which falls under our consideration is the DayBook, which, as we formerly remarked, might be more properly denominated Goods-Book, as it contains the particulars of the purchases and sales of Goods on credit; but this term is too limited, if, as is generally done, it is made to contain the par ticulars of all other transactions which do not strictly belong to the Cash-Book or the Bill-Book. In mercantile houses, where the particulars of important transactions are numerous and minute, as in the case of the entries of invoices of the shipments of Goods, and the sales of consignments, it is usual to make only an abstract of these particulars, and to refer to the Invoice Book and the Sales-Book for those which are necessarily omitted. In like manner, when the particulars of Insurances on Goods. Speculations in inland or foreign produce, or Adventures to or from foreign countries, become too numerous or cumbersome to be entered at length in the Day-Book, references must be |