participles of active verbs must adopt the number and gender of the word to which they refer, which will be explained later. non ve n'è-ra-no che du-e, there were only two of them; medi-ci qui non ce ne só no, there are not any physicians here; non cré-do che ve n'ab-bia, I do not believe that there are any of them here. VIII. There is, there are, etc., is sometimes expressed by si dà, si dán-no, etc. (from dá-re, to give), e. g. non si dà al móndo cô-sa peg-gió-re, there is not any thing worse in the world; si dán-no di quél-li che so-stên-gono. there are some who maintain ...; dán-no-si qui de' gran com-mer-cián-ti? are there great merchants here? IV. For the negative form of the auxiliaries avere and essere, and indeed of all other verbs, non is used, and always placed before the verb, e. g. non avere, not to have; non essere, not to be; non avendo, not having; non essendo, not being; non avere avuto, not to have had; non essere stato or stata, not to have been; non avendo avuto, not having had; non essendo stato or stata, not having been; io non ho, tu non hai, etc., I have not, thou hast not, etc.; io non ho avuto, I have not had, etc.; io IX. The words ci and ei, here, there, in this or that place, non sono, tu non sei, etc., I am not, thou art not, etc.; io non merely being local adverbs, it is clear that they must be supsono stato or stata, I have not been, etc. In the interroga-pressed when speaking of time, e, g. è un mé-se, só-no dú-e ántive form the personal pronouns are of course put after the ni, it is a month, it is two years; pô-chi mé-si só-no (or fa), it verb, and, when omitted, the inflection of the voice must, to is a few months, or a few months ago; è un bel pêz-zo, che non some extent, supply their place, e. g. ho io? have I? hai tu? | l'hô ve-dú-to, it is some time since I have not seen him; ciò hast thou? ha egli? has he? abbiamo noi ? have we? avete voi? ac-cúd-de dú-e mé-si fa, this happened two months ago. have you? hanno eglino? haye they? ho io avuto? have I had, etc.; sono io? am I? sei tu? art thou? è egli? is he? siamo noi? are we? siete voi? are you? sono eglino? are they? sono io stato or stata? have I been? etc. In the negative and interrogative form, the auxiliary or (in simple tenses) the verb is placed between the negation and the pronoun, e. g. Non sono io? am I not? Non ho io? have I not? FRENCH READING S.-No. XVIII. JOSEPHINE MARIE ROSE TASCHER de la PAGERIE, impé Non sono io stato have I not Non ho io avuto? have I not ratrice des Français, naquit à Saint-Pierre de Martinique, been? Non era io? was I not? had? Non aveva io? had I not? Non era io stato? had I not Non aveva io avuto ? had I not been? Non fui io? was I not? had: Non ebbi io? had I not? Non fui io stato? had I not Non ebbi io avuto ? had I not been? Non sarò is? shall I not be? have been? Non sarei io? should I not be? Non sarei io stato? should I not have been i etc. had? V. The phrases there is, there are, there was, there were, etc, (equivalent to the French il y a, etc.), are generaliy expressed by the auxiliary essere, before which the adverbs ci or ti are placed. Essere, in this case, must agree in number and gender with the noun that accompanies it, e. g. c'è or v'è, there is; ci sono or vi sono, there are; c'era or v'era, there was; c'erano or v'erano, there were; ci fu or vi fu, there was; ci furono or vi furono, there were; c'è or v'è stato or stata, there has been; ci or vi sono stati or state, there have been (and so of the other tenses); c'è or v'è ú-na gran quan-ti-tà, there is a great quantity; ci só-no or vi só-no dél-le per-so-ne, there are persons; d'é-ra ú-na vôl-ta un sá-vio Grê-co, there was once a wise Greek; v'ê-ra-no de' pô-po-li, there were nations; c'è stá-ta u-na can-tatri-ce, there has been a (female) singer; ci só-no stá-ti de' princi-pi, there have been princes; c'è or v'è, êc-ci or iv-vi qui un qual-che mê-di-co? is there some physician? VI. In similar cases avere (with vi before it) may be used for essere, and even stand in the singular, though the accompanying noun is in the plural, e. g. vha (for v'hanno) de' princi-pi, there are princes; v'ha mol-te co-se, there are many things; v'ha or hav-vi mól-ta gên-te pô-ve-ra, there are many poor people; mól-ti sol-da-ti v'a-vé-a, there were many sol diers. VII. When there is, there are, and similar phrases, have the words some, some of it, some of them, of it, of that, of them, of the number, etc., joined to them, the latter words must be expressed by the particle ne, equivalent to the French en, and the adverbs ci and vi changed into ce and ve before ne, e. g. ce n'è or ve n'è, there is some; ce ne sono or ve ne sono, there are some; ce n'era or ve n'era, there was some; ce n'erano or ve n'erano, there were some, etc.; non ce n'è più, there is nothing more of it; ce ne só-no mól-ti, there are many of them; le 24 juin, 1763. Fiancée dans son enfance au second Antilles, elle fut amenée fort jeune en France. Joséphine, fils du marquis de Beauharnais, gouverneur général des belle de toutes les grâces réunies de la personne, du cœur et de l'esprit, fut regardée dès son entrée dans le monde comme l'une des femmes les plus charmantes de Paris.3 According to the rule that a monosyllable like è, in compositions, loses its accent and doubles the initial (unless an impure) of the suffixed word. Elle eut deux enfants: Eugène, né en 1781, et Hortensed née en 1783.4 En 1787, elle s'arracha à tous les plaisirs du monde pour aller revoir sa mère à la Martinique. Elle y resta trois ans. Les troubles qui éclatèrent en 1790 dans la colonie la forcèrent à s'enfuir précipitamment.' Elle revint en Frances après avoir échappé à mille dangers. Son mari, nommé successivement membre de l'Assemblée nationale, président de cette même assemblée, puis général en chef de l'armée du Rhin,' fut ensuite dénoncé et emprisonné 10 aux Carmes. Elle partagea sa captivité. Joséphine, condamnée à mort avec lui, ne dut la vie qu'à un évanouissement" où elle tomba en voyant partir son mari pour l'échafaud. L'état de faiblesse où elle se trouva fit ajourner sa mort. Quatre jours plus tard, le 9 thermidor, ramena, au pouvoir le parti auquel avait appartenu le général Beauharnais,12 et, quelque temps après, Tallien la fit sortir de prison.13 Protégée par Barras, elle rentra bientôt dans une partie des propriétés de son mari.11 15 14 Il l'aima dès Lorsque après le 13 vendémiaire, le gouvernement ordonna le désarmement des citoyens, le jeune Eugène, âgé de quinze ans, alla, envoyé par sa mère, trouver le général Bonaparte,16 pour lui redemander l'épée de son père, qui lui avait été enlevée, le général frappé de l'énergie du jeune homme voulut connaitre sa mère.17 qu'il la vit, et il l'épousa' en 1796.18 Joséphine suivit son époux aux armées, adoucissant par ses graces l'humeur quelquefois sombre du jeune héros, et par sa bienfaisance les horreurs de la guerre. Je gagne les batailles, et elle les cœurs, disait Bonaparte à cette époque. Pendant l'expédition d'Egypte, où son mari ne voulut pas qu'elle l'accompagnât, elle se retira à la Malmaison, 20 petit château qu'elle avait acheté près de Paris. 9. A quel poste son mari arait-il été nommé? 10. Qu'arriva-t-il ensuite au général Beauharnais ? 11. A quoi Joséphine fut elle redevable de la vie? 12. Qu'arriva-t-il quatre jours plus tard? 13. Comment obtint elle sa liberté ? 14. Que! fut l'effet de la protection de Barras ? 18. En quelle année Bonaparte 20. Accompagnat - elle son NOTES AND REFERENCES.-4. from naître : L. part ii., p. 96. -b. L. part ii., § 23, R. (5).-e. L. S. 45, R. 2.-d. from naître; see note a.—e. Carmes, a Carmelite convent, then used as a prison.-f. L. part ii., § 49, R. (1).—g from devoir.—h. L. S. 25, R. 3.-i. L. S. 66, R. 2. SECTION II. comme avant son élévation? 11. Comment les grands font ils ordinairement le bien? 12. Comment secourait-elle les 13. Recevait-elle tous les infor- 14 Que trouvaient ceux que les 15. Qu'aimait Joséphine? NOTES AND REFERENCES.-a. from devenir; L. part ii., p. -c., L. 231.88.-b. from devoir; see also L. S. 84, R. 2, 3, L. part ii., § 49, R. (1.)—e, from connaitre; L. part ii., p. 82. L. part ii., § 138, R. (2).—g. L. part ii., § 145, d. CORRESPONDENCE. PERSEVERANCE IN LEARNING, La Malmaison, dont elle fit l'asile1 des arts, des sciences et de l'esprit, devint, au retour d'Egypte, la retraite "A taste for literature is almost equivalent to another sense." chérie de Bonaparte, le lieu qui le vit monter au faîte des grandeurs et qui l'en vit redescendre, car ce fut de là qu'il SIB, You have so nobly succeeded in placing the fulcrum of partit pour s'embarquer sur le Bellerophon. L'élévation your mighty educational lever on a firm and popular basis, that the successive do Bonaparte au consulat et à l'empire, n'éblouit standard of intellect among your students is evidently being pas un moment Joséphine; elle ne fut pour elle que l'oc-direct conjunction with your truly great production, the POPULAR raised, through the powerful instrumentality of self-exertion in casion de soulager plus de malheurs. Sous le consulat, EDUCATOR. une foule d'émigrés durent à ses instances leur radiation The humblest youth in society, with meagre earnings and but de la liste des proscrits. Elle sauva la vie à MM. de little leisure, has now a fair opportunity of becoming a respectable Polignac et de Rivière, condamnés à mort. scholar if he only labours with ordinary zeal and attention. In the POPULAR EDUCATOR (it is the opinion of competent Mais, si elle protégea" efficacement ses anciennes con-judges) the different subjects are commenced with such wonderful naissances de la noblesse, elle ne connut jamais la sottises simplicity, and their principles so clearly and so gradually devede la morgue aristocratique; et quoique élevée sous l'an-loped, that the mind is led, almost imperceptibly, "from the known cien régime, la justesse de son esprit lui fit comprendre et to the unknown," with astonishing ease and quickness. Yet, sir, partager l'idée dominante du siècle, l'égalité. Après there must be exertions made to "drink deep." Your students comme avant son élévation, elle secourait toutes les infor- that of Hercules when he set out in search of the brazen-footed must labour, and toil, and persevere, with a fortitude no less than tunés sans distinction de rang, et non pas à la façon des stag; and, like him, after a year's chase, they will be stimulated grands, qui se contentent de faire le bien par ordre, mais to snatch new trophies, by the very fact of their laudable success. en recherchant, en recevant elle-même les malheureux, No use in wishing-no use in lying at our ease, and plucking the en entrant dans le détail de leurs souffrances, et conservant flowers at the foot of the mountain; such dull pastime we leave to leurs récits gravés dans sa mémoire. Toutes les douleurs march is onward--come, boys, move up! By perseverance, Napothe idle truants, if such there be in our present generation; our avaient accès auprès d'elle, et celles que les dons pécu- leon brought his heavy artillery across the Alps; every obstacle is niaires ne pouvaient soulager, trouvaient dans la sensi-superable where the mind is willing. Eut in study, as in walking, bilité de l'impératrice cette espèce de charité que l'on "Begin with gentle toils, and as your nerves rencontre si rarement chez les princes. Grow firm, to hardier, by just steps aspire." motion. Joséphine aimait les arts15 et les sciences; tout ce qui Perseverance in the acquisition of knowledge implies the presence était beau et utile était sûr d'avoir en elle une protectrice of a grand mental superiority, before which every obstacle must éclairée et généreuse. Elle oubliait alors de calculeris ses ultimately vanish like a giant of snow before the rays of the sun. Is there poverty to contend with? Nonsense! Mental power ressources, et embarrassait ainsi souvent ses finances. Le never considered ordinary poverty an embarrassment to its onward talent passait pour elle avant le succès; elle le soutenait de march. On the contrary, it has ever been the mighty element toutes ses forces. Nous n'en citerons qu'une preuve entre that stimulates to action those energies which otherwise might mille; ce fut elles qui reconnut et encouragea Prud'hon, have lain dormant, like an inorganic mass, absolutely incapable of l'un des plus grands peintres de l'écoles française. "The schoolmaster is abroad," and unless we are greatly on La botanique était l'étude's favorite de Joséphine. Elle the alert, we might soon blush to find ourselves half a century in rassembla à la Malmaison une collection20 de plantes rares, the rear of the present generation! Certainly, in a retreat the rear pour la plupart inconnues en France; et tols étaient les is the post of honour-not so, my boys, in the march of intellect; égards qu'amis et ennemis avaient pour elle, que le prince for "emulation hath a thousand sons."" No loitering-the noble regent d'Angleterre ordonna à la marine anglaise de res- phalanx moves on, and our neglect of duty is equal to a desertion of the literary standard. "No royal road to literature." Had we pecter les envois de plantes qu'on lui faisait de toutes les velvet lawns, gorgeous canopies, and stupendous arcades, we parties du globe. would faint in the arms of luxury. Nothing like the bold and rugged steep where the cold blast pierces but invigorates, and as it sweeps by, "hope in the gale" animates the intrepid aspirant with new power. On!-see the SELF-TAUGHT battalions in lightmarching order!-how they advance across the plain, and ascend the steep, with a hearty huzza for the POPULAR EDUCATOR! COLLOQUIAL EXERCISE, 1. Que fit Joséphine de la Malmaison? 2. Que devint ce château au retour d'Egypte? 3. Quel effet l'élévation de Bonaparte eut-elle sur Joséphine? Que fut pour elle cette élévation? 5. Que lui durent plusieurs ment? 8. Que ne connut-elle jamais? Up, slumbering truants! Join the ranks, and your scientific march will soon prove more natural than the rust-like dishonours of useless and corroding ease. Perseverance brought Sir Cloudesley Shovel from the post of cabin-boy to the highest honours of his profession. Thomas Simpson, from being a weaver-boy, rose to the dignity of a professorship at Woolwich, and he became a member of the Academy of Sciences at Paris. James Stuart, the great architect, was a poor widow's son. When very young, he went about painting fans to procure a morsel to maintain his mother and the rest of the family. He afterwards went to Italy and Athens, where he became truly celebrated; and was subsequently appointed Surveyor of Greenwich Hospital. He is, by way of eminence, called the Athenian Stuart. Terence, the poor African slave, became a famous dramatic writer; and is as remarkable for his spirit of gratitude towards his generous liberator as for his shining talents. See, young reader, what even barbarous Africa can produce. Nicholas Reymanus, the great Dutch mathematician, was, in early life, a swineherd, and was eighteen years of age before he learned to read; but so incessant was his labour, and so rapid his progress, that he afterwards taught mathematics at Strasburg, obtained a professorship at Prague, and became such a master of science as to dispute with the famous astronomer Tycho Brahe, concerning the right to some astronomical discovery. Cervantes, the celebrated Spanish writer, and author of "Don Quixote," a powerful satire on the books and the profession of knight-errantry, was a common soldier, and lost his arm at the battle of Leputa. Here I pause; and, reader, talk as you will about the force of genius in those men, you may rest assured that the spirit of indomitable perseverance led them on through every difficulty. An eminent writer, giving advice to a young student, says: Live like a hermit, work like a slave, learn everything, and shun popular pleasure. "If one hour you dedicate to reading, give two to reflection, and three to observation. Deem no art or science useless. Accustom yourselves to act as well as to think. this subject, I can be seen at any time after six o'clock, evening. Monkwearmouth, Sunderland. [We have inserted the above letter as a fair specimen of many that we have received since we commenced our labours; and these labours have been nobly appreciated, and wisely appropriated, by many thousands of our working population-our country's wealth, stability, and pride. We hope that our correspondent will meet with many in the town and suburbs of Sunderland who will answer his invitation. Such a man, by simple means such as he has proposed, may do a vast amount of good in his day and generation. -ED.] ANSWERS TO CORRESPONDENTS. 1. D. (Brighton): Yes.-M. E. L. (Borough): Your hand-writing is good, 1. O. U. (Liverpool) has not seen the 2nd and 3rd vols. of the P. E.also necessary, which you seem to possess. We shall be glad to recommend and well adapted for an amanuensis. Good spelling and composition are you if an opportunity should occur; but opportunities are rare.-A. HARDMAN (Manchester) is right.-W. MARTIN (New Swindon); D. H. S. (Liu"Confirm reading by practice, and improve practice by reading.colnshire); W. A. (Woolwich); F. H. B. (Halifax); A. BOYD (Glasgow); Store your mind with all sorts of knowledge; you never know J. 1. SNOWDON (Otley); MARIA M. LEATH (Otley); and J. RUSSELL when it will be required; even that which is most useless will (Chislehurst): All right about the Pine-tree and the Lady's age.-L. R. J. always prove ornamental. For methods, make your own, adapt those cost 48. Gd. each, or two vols. in one, 8s. 6d. The English and French are (Manchester): The first three vols. of the P. E., separately bound in cloth, which you find most apt; experience in this will be the best the most useful languages in a place of business like Manchester. Right in teacher, your own habits the best adviser. There is no royal the Lady's age.-A. GEARING (Leamington): His expression for the circumroad to knowledge, and but one golden rule, and that is mental ference of the circle is pretty fair, but it is correct only to the figures 3.1415, labour, work, work, work." the next figure being zero instead of 9.-J. F. ATKINSON (Birkby): We Here, readers, is an extract worthy of your attention, for before shall be glad to see his solutions, believing them to be done bona fide.— J. MATHER (Derby): Many thanks.-EDWIN LONE (Cheshire): Very well. the powers of application every thing must bend. You have J. LONRY (Armagh): See the scholastic advertisements in the "Times" difficulties to contend with, so has every one; but the giant might newspaper.-E. SUTTON (Retford) had better call when in town.-N. M. L. of rational resolve scarcely admits of any. (Tottenham-court-road): None at present.-BLANDUS: Right in the Lady's age. The Hebrew may be the oldest, but it is not the easiest language. You cannot learn or understand the Hebrew without the points; there is no fashion in the matter; it is a question of pure necessity.-J. JONES (Woolwich): His solution of the Pine-tree question is good.-UNE AMIE AU P. E. (Leicester): Many thanks for her communication and kind wishes.JOHN POGSON (Mossley): His solutions received. Chevenix, on National Character, says;" The most advantageous situations in which human beings can be placed is, that in which they are surrounded by superable obstacles." And now, fellow-students, I must bid you good-bye for the present, hoping soon to meet you again on the educational arena of the POPULAR EDUCATOR; and, my boys, let those who will take volo non voleo for their motto; ours must undoubtedly be Ne cede malis sed contra audentior ito, shining in relievo on our escutcheons. I am, Mr. Editor, with the warmest feelings of respect and gratitude, one of your humble students, H. H. ULIDIA. Katesbridge, June 15th, 1854. [There is so much of good feeling and good sense, as well as of the perfervidum ingenium Scotorum, in this letter, that we could not refuse it a place; especially as it urges our students to perseverance in a more lively strain than we are likely to do, were we to take up the pen. At the same time, coming from a fellow-student (who has given us his name and address), it is more likely to have a good effect on some of our undecided readers.-ED.] SELF-EDUCATION AND MUTUAL INSTRUCTION. SIR,-About the time you commenced your laborious work, it happened, by chance, that I was passing a booksellers's shop window, and saw there the third number of the POPULAR EDUCATOR. I read all that I could see,-"On the Influence of Morality and Immorality on the Countenance." I looked to see the price of it, and found that it was a penny; that sum being all I had in my pocket, I purchased it. I then took out my pen-knife and cut open the leaves, in order to finish what I had read through the windows. To my great surprise, I found Dr. Beard's Lessons in Latin. I then turned over another leaf, and found Lessons in Arithmetic; and then next, I found Lessons in English; and it gave me great pleasure to think that such a work was to be had at so low a price. I have continued to take it in ever since, up to the present time. I then commenced the study of the Lessons given in Arithmetic, which has improved me so much, that I have got as far as Simple Interest with wonderful success. Before I saw the POPULAR EDUCATOR, I knew nothing about arithmetic; I had got so far as Compound Proportion, but in such a wretched state, that I could not master it. Now, sir, there is no Co-instruction Society at Sunderland, as yet, that I know of; but there are a great many who take in the POPULAR EDUCATOR, and a great many more who would like to do so, and to have a good education. If you can do anything to draw us together, I will give you my address, and will do all that I can for any one that calls on me; if there be any wishful to see me on LITERARY NOTICES. Now Ready, CASSELL'S FRENCH AND ENGLISH DICTIONARY: Composed from the French Dictionaries of the French Academy, Bescherelle, Landais, etc.; from the English Dictionaries of Ogilvie, Johnson, Webster, etc.; and from the Technological and Scientific Dictionaries of both Languages. The following are the distinctive features which render this Work superior to any of the same class now extant. It has been compiled with unusual care from the very best authorities. It contains correct renderings of all the most modern words and phrases-including those of science, art, manufacture, commerce, law, politics, etc., as well as familiar conversation--which are indispensable to a knowledge of language, but yet are rarely, if ever, to be found properly translated in any Dictionary. The idiomatic usages of the two languages-the constructions of verbs, the force of prepositions, and the changes of meaning caused by different combinations of words-are limits. The meanings are also classified and arranged in such a manner as more copiously and carefully illustrated than elsewhere within the same to prevent the possibility of mistake. To crown all, the Work is as moderate in price as it is comprehensive in aim, accurate in detail, and superior in arrangement. Price 9s. 6d. strongly bound. CASSELL'S LESSONS IN FRENCH. Parts I, and II.-By Professor FASQUELLE. 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In one large handsome Octavo Volume, price 98. strongly bound. ON PHYSICS, OR NATURAL PHILOSOPHY. (Continued from page 242.) SOURCES OF HEAT. bon which is converted directly into carbonic acid, disengages the same quantity of heat as if it were first converted into carbonic oxide, and then the latter into carbonic acid. The heat produced by a burning body is distributed in two ways; first, by the calorific rays which proceed directly from the body; secondly, by the heat which the particles, after being converted into carbonic acid, carry along with them, when drawn up by a current of air. By the latter way, a very Chemical Combinations.-Chemical combinations are gene- ascertained by any one by means of a very simple experiment, considerable proportion of the heat escapes, as may be easily rally accompanied by a development of heat more or less abund-shown in fig. 229. Thus, we find that we can hold the finger ant according to the nature of the substances. When these combinations operate slowly, as when iron is oxidised in the air, the heat developed is insensible; but when they are produced rapidly, as in the mixture of anhydrous sulphuric acid with water, the disengagement is very intense. In most cases, this disengagement of heat is accompanied with combustion. Combustion. Every chemical combination which is accompanied with the development of light and heat, is called combustion. In the combustions presented to us by wood-fires, oil-lamps, and wax-candles, it is the carbon and the hydrogen of the wood, the oil, and the wax, which are combined with the oxygen of the air. But there are combustions in which oxygen plays no part. For example, if into a vessel full of chlorine, we throw some powder of antimony, or pieces of phosphorus, these bodies will combine ith the chlorine and produce a powerful development of light and heat. Several combustibles burn with a flame. A flame is, in fact, only a gas or a vapour carried to a high temperature by the effect of combustion. Its illuminating power varies with the products which are formed during combustion. The presence of a solid body in a flame increases its illuminating power. The flames of hydrogen, carbonic oxide, and alcohol, are pale, because they only give out gaseous products. But the flames of waxcandles, oil-lamps, and carburetted hydrogen gas, have a great power of illumination, because they contain an excess of carbon, which, undergoing only an incomplete combustion, become incandescent in the flame. Much greater intensity is given to a flame, by placing in it platinum wire or amianthus. The temperature of a flame has no specific ratio to its illuminating power. The flame of hydrogen, which is the palest, is that which developes the greatest heat. Heat of Combustion.-Several philosophers, among whom may be mentioned Lavoisier, Rumford, Dulong, MM. Despretz and Hess, have been engaged with researches relating to the quantity of heat developed by different bodies during combustion and combination. In these researches, the calorimeter of Rumford was employed. It consists of a rectangular copper vessel filled with water, in which a worm is placed, passing through the bottom of the vessel and terminating below in an inverted funnel. Under this funnel are placed the burning bodies on which the experiments are made. The products of combustion, by being disengaged in the worm, heat the water in the vessel, and after the elevation of its temperature, the quantity of caloric developed may be determined. Assuming as the unit of heat, the quantity of caloric necessary to raise one kilogramme of water by 1 Centigrade, Dulong found that a kilogramme of the substances in the following table disengaged in their combustion the number of units placed in a line with their names : Fig. 229. or thumb at a small distance from the side of the flame of a lighted candle, without feeling the heat too intense to bear its action; but when we hold the finger above the flame, in the direction of its axis, we are forced, by the greater heat evolved in this direction, to remove it to a much greater distance. ILLUMINATION. Modes of Lighting.-As the method of producing an artificial light for the purpose of supplying the want of the light of the sun, is more connected with the principles of flame, combustion, and heat, than with light considered by itself, we shall treat here shortly on this subject. The light of a common fire was naturally the first step in the art of illumination. The property which resinous woods possess of giving out a flame not only continued difficult to extinguish, but soon led to their use in the form of torches. Virgil speaks of them in the 2nd book of the Georgics, and in the 7th book of the Eneid. "Ipsa inter medias flagrantem fervida pinum Sustinet." This mode of lighting is still used in some countries to this day, as in Corsica and in China; but on account of the smoke it can only be employed in the open air. The inflammability of oily bodies, and especially of animal fat, must have been tions in the remotest times. The substitution of the pure discovered in the practice of the most simple culinary prepararesinous matter for the branches which contain it, the extraction of animal fat and vegetable oil, were grand steps in the progress of the art of illumination. Resinous matter, solid grease and wax fixed round a wick composed of fibrous matter, gave rise successively to the torch, the candle, and the waxlight. Oil, extracted either from animal or vegetable matter, was burned in lamps, which were at first small vessels furnished with a hollow beak or spout, in which the wick was placed. In all these cases, whether lamp, candle, or torch, the combustible matter melted by the heat, rose in the wick in consequence of capillary action, as formerly explained. Small resinous torches, manufactured from the products of the pinus maritima, on a large scale in the moors of Gascony, are still, in many parts of France, the only mode of lighting employed during the long nights of winter. The gaseous products of the combustion are carried off by the chimney, under the mantelpiece of which the torches are placed. The unhealthy candle, compared with this imperfect light, was a vast improvement. But the candle is beginning to disappear in our towns, in order to give place to the stearic wax-lights, which are only half the price of the real wax-lights, and have an equally pure smell. The modern lamp, successively modified by Argand, Carcel, and others, has only a very distant resemblance to the lamps of antiquity. Whatever be the substance used in the The experiments of Dulong, M. Despretz, and M. Hess, production of the light, the flame, which is the illuminating establish the principle that a body which burns produces cause, is the result of the combustion of a gas more or less always the same quantity of heat in order to arrive at the charged with solid particles. This will be explained by fig. same degree of oxidation, whether this degree be reached 230, in which AA is a vertical section of a candle through the immediately or by degrees. For example, a quantity of car-niddle. BB, is the cotton wick which is set on fire. The 121 Substances. Protocarburetted hydrogen ... ... Hydrogen Olive oil Oil of turpentine Bicarburetted hydrogen Sulphuric ether Pure carbon Alcohol Sulphur Carbonic oxide VOL. V. Units. 9430 7295 6855 2601 2488 width of the cylindric roll of tallow bs been calculated in such a proportion to that of the wick, that its edges do not melt, but form a wall which hinders the m lted matter from gutter ing. Thus the melted grease is contined as it were in a small cup, represented at c c, and forms a bath of a suficient depth Fig. 230. The small transverse or horizontal marks, represent the place occupied by the particles of oxygen; the round points on the neary vertical lines, represent the place occupied by the particles of hydrogen. It is quite evident that the most active combination takes place in the exterior part, where the particles of both gases are in immediate contact; and that it goes on diminishing from the border to the centre of the flame, where there is none. What the candle, the wax-light, and the lamp realise on the small scale, and simultaneously with the process of combustion, has been effected on the great scale, and previously to combustion itself; in other words, we extract the carburetted hydrogen gas from the bodies which coutain it, and we burn it by means of gas-burners properly supplied with it. This invention is entirely a modern one. Notwithstanding the ultimate resemblance which exists in all these various modes of illumination, there are particulars belonging to each worthy of notice. all round the wick nn, of which the fibres are similar in effect Candle Lights-In the manufacture of candles, a mixture of beet and mutton tallow is preferred. The former alone is too soft and too easily melted; while the latter gives less light, as being too difficult to melt. The raw tallow, separated as much as possible from foreign matter, such as blood, etc., is first chopped small, and then melted in cast-iron or copper vessels. It is then passed through a strainer in order to purify it, sometimes more than once, if necessary. The wicks are made of cotton; they must be free from knots, slightly twisted, and perfectly dry. The proper lengths are cut by the hand. There are different processes for fixing the candle round the wick. The oldest and simplest consists in dipping the wick, for some instants, in the purified tallow, stretching it and rolling it in the hands or on a table. The wicks thus prepared, are suspended round a circular frame, balanced by a counter-weight, by means of a pulley fixed to the ceiling. By pressing slightly on the frame, the wicks are dipped in the melted tallow at as low a temperature as possible. When they are covered with a layer of sufficient thickness, the frame is permitted to ascend by the action of the counter-weight, and the candles, or rather partially coated wicks, are allowed to cool in the air, until they are ready for a new dip in the melted tallow, by which they are covered with a seat as before; this process is continued until they have a the necessary thickness. Thus are the ordinary dip-cas made. Mould-candles are made in the following manner:-The moulds are composed of a mixture of 1 part of tin and 2 parts of lead, well polished in the inside, and formed in the shape of a candle. These moulds having been fixed in a vertical position, the wick is passed through them, stretched, and centrally fixed in that position. The tallow is then poured into them at a very gentle heat; for if too hot they would stick to the moulds. As candles grow old, they whiten and become of a better quality. Prolonged exposure to the air or to the dew hastens the whitening process. Wax-lights. In the same manner as candles are moulded, so are wax-lights, only they are more apt to adhere to the sides of the mould, which renders the operation more difficult. The mode of their manufacture differs very little from that of candles. By means of a spoon or ladle, the melted wax is poured successively over the top of the wick, along which it cools and solidifies. When they have reached the proper thickness, they are lifted and rolled on a table to give them the proper regularity of form; a process which is aided by the use of a polished board instead of the hands. Spermacets candles have long been in great demand on account of their transparency and whiteness. They are moulded, and in their manufacture a solid substance called spermaceti, expressed from the brain of the whale, and purified, is employed, but it is mixed with about 3 per cent. of very white wax. Sometimes a small quantity of colouring matter is introduced into wax-lights, but this has no influence on the brightness or the colour of the light. Stearic-lights.-The manufacture of stearic candles originated with MM. Gay-Lussac and Chevreul, who took out a patent for them in France, in 1825. They are made of solid and inodorous substances called stearic acid and margaric acid, which are chemically extracted from tallow or fat, the residue yielding glycerin and oleic acid. Stearic is prepared by saponifying beef or mutton tallow by lime; 1000 lbs. of tallow and 176 gallons of water are placed in a wooden vat, capable |