Sitio 4, I thirst (sitierunt is a syncopated form for sitiverunt); esurio 4, I am hungry; tenuis e, thin; membrăsum, i, n. a leaƒ, or covering; vestio 4, I clothe (E. R. rest); paries, ĕtis, m. a wall; coróna, ae, f. a crown, chaplet; placeo 2, I please; navigo 1, I sail (E R. navigate; munio 4, I fortify; dormio 4, I sleep; simulac, as soon as ; antequam, before that; expedio, with the reflective pronoun, I preare; gario 4, I chatter; Lacedaemonii, orum, m. the Spartans; specto Iregard (id spectant, have this object); custodio 4, I keep, guard; Senio 4, I soften, soothe; punio 4, I punish; obedio 4, I obey, governs the dative (obedieratis, syncopated for obediveratis); prodest, he benefits. EXERCISES.-LATIN-ENGLISH. Milites per totum diem sitierunt et esurierunt; natura oculos tenuissimis membranis vestivit; cur domûs vestrae parietes coronis ornavistis et vestivistis? praeceptoribus vestris placueratis, quia semper praeceptis eorum obedieratis; vix milites nostri castra muniverant, quum Caesar aciem instruxit; non prius dormiemus quam negotia nostra finierimus; quum milites castra muniverint, ad pugnam se expedient; cavete, pueri, ne garriatis; Lacedaemoniorum leges id spectant ut laboribus erudiant juventutem; nemo dubitabat quin pueros semper custodivisses; narrate mihi quâ consolatione aegrum amici animum leniveritis; nescio cur puerum puniveritis; non dubitabam quin praecepta mea memoria custodivissetis; ne garritóte, filiae; venio te rogatum ut mecum ambules; milites urbem custodire debent; sapientia est ars videndi; obediendum est praeceptis virtutis; ars navigandi utilissima est. ENGLISH-LATIN. They thirsted; I shall be hungry; thou wilt not obey my precepts; the boys chatter; they have not obeyed their father; I know not why they have not obeyed their father; no one doubts that good boys obey their father; he kept my words in memory; I shall take care that thou keepest (mayest keep) my words in memory; they come to fortify the city; the art of writing is useful; they adorn the walls of their house with chaplets; I shall not sleep until (before that) I have (shall have) finished my business; hast thou finished thy business? he was punishing the boy when I entered the school. PERFECT Plural. Sing. Sing. 11. FUTURE. Plural. PLUPERFECT. Sing. Plural. Subjunctive. auditus auditus sum auditus sim auditus est auditus sit auditi sumus auditi simus auditi estis auditi sitis Infinitive. Participie auditum EXERCISES.-LATIN-ENGLISH. auditun Pater curat at filius bene erudiatur; pater curabat at filius bene erudiretur; cives metuant ne castra ab hostibus ante urbem muniantur; oculi tenuissimis membranis vestiti sunt; quum rex urbem intrabat, omnium civium domus coronis et floribus vestitae et ornatae sunt; non prius dormiemus quam negotia vestra finita erunt; simulac castra munita erunt, milites se ad pugnam expedient; metuebamus ne urbs ab hostibus obsidione cincta esset; improbi puniuntor; bonus discipulus literarum cognitione erudiri studet; urbs, obsidione cinctâ, multis malis punitur; vir eruditus non solum sibi sed etiam aliis prodest; pueri diligenter erudiendi sunt. ENGLISH-LATIN. They are guarded; the city is guarded; the city will be guarded; the city has been guarded; I take care that the city is (may be) guarded; no one doubts that the city is well guarded; the citizens ought to guard the city; why do not the citizens guard the city? I know not why the citizens do not guard the city; I fear the citizens may not guard the city; they have prepared for the fight; the walls of the house have been clothed with flowers. LESSONS IN PHYSIOLOGY.—No. X. MAN. THE structure of our bodies may be perfect-they may be possessed of all the properties which are required for their activity, but this activity would never be put forth without the stimulation of heat. This is essential to every action of life. Why are persons sometimes frozen to death, but because, under the extreme cold to which they are exposed, they are not able to keep up the temperature of the body? In man, the standard heat is from ninetyeight to one hundred degrees; and it is well known that whatever may be the state of the air by which we are surrounded,-whether we be in the polar regions, or in the torrid zone,-under any variety of circumstance, the body retains nearly the same temperParticiple. ature. This is a property peculiar to life; and "without this power of adaptation, it is obvious that man must have been chained for life to the climate which gave him birth, and even then have suffered constantly from the change of seasons; whereas, by possessing it, he can retain life in a temperature sufficiently cold to freeze mercury, and is able for a time to sustain, unharmed, a heat more than sufficient to boil water, or even to bake meat." This uniform temperature is effected by the production of heat sufficient to compensate for that which is constantly lost in radiation, or in the evaporation which takes place from the exposed surfaces of the body. In proportion as the external temperature is low, it is needful that more heat should be generated and evolved to keep up the temperature of the body to its proper standard. If the surface is exposed to a high degree of external heat, then the temperature of the body is kept down by the increased amount of fluid which is set free from the perspiratory glands; this fluid is carried off by perspiration in a state of vapour, and withdraws a certain quantity of caloric or a certain degree of heat from the surface. As a rational and intelligent being, man has the power to adapt himself to the extremes of heat and cold, and to every possible variety of climate. His intelligence will be seen in the choice of auditum audiendus his food, his clothing, his occupation, and even his amusements. healthy and vigorous an infant may be at its birth, it has not the He may live in either zone, or within the zones, and enjoy the ful-power to keep up the standard heat of the body without assistance; ness of health. and exposure to a cold atmosphere would be followed by the most serious or fatal consequences. It is a well-known fact, that during the first month of infant life, the mortality in winter is nearly double that of summer. In adult life, on the contrary, when there is the power of maintaining a high independent temperature, the deaths in winter are scarcely one-sixth more than in summer. In old age, the power of generating heat again diminishes, and the relative mortality is nearly the same as in the first month of infancy. At the age of ninety, the average of deaths in winter are more than twice those of summer. Great attention, then, should be paid to the temperature of the body by every one who wishes to enjoy health. Care should be taken to select a dry atmosphere, and avoid all damp and marshy situations. If the air be saturated with vapour, it will interfere with the healthy functions of the skin, and so derange the whole system. But what is the source of this animal heat? If it be so essential to vital action how is it produced? It was long before this question came to be satisfactorily answered. But now the general opinion is, that it is owing to certain chemical processes going on in the system, and that these chemical changes are carried on in parts whose functions are, to a certain extent, under the influence of the nervous system. In warm-blooded animals,* the blood receives from the digestive canal and the lungs, more carbon, hydrogen, and oxygen, than are consumed in the repair of the tissues, and from the combination of these elements is always parting with a certain quantity of carbonic acid and water. Now in the process of this combination, heat is continually produced in the animal body; and the illustrious Liebig believes that the union of the oxygen absorbed into the blood from the air which we breathe, by being united with the carbon and hydrogen which are taken into the system as food, is sufficient to account for the whole of the heat which is formed in the body. It is laid down as a general rule, that, in the various classes of animals, "the quantity of heat generated in the body is in direct proportion to the activity of the respiratory process. The highest animal temperature is found in birds, in whom the function of respiration is most actively performed. In mammalia, the process of respiration is less active, and the average temperature of the body less than in birds. In reptiles, both the respiration and the heat are at a much lower standard; whilst in animals below them, in which the function of respiration is at the lowest point, a power of producing heat, is, in ordinary circumstances, hardly discernible." Other equally interesting facts come in to confirm this theory. It appears that in the vegetable kingdom the degree of heat which is evolved by plants, is in proportion to the amount of oxygen which they absorb and convert into carbonic acid. In the germination of seeds there is a considerable elevation of temperature. A thermometer introduced into a flower during the time of flowering has been known to rise to 112°, while the temperature of the surrounding air was not much more than one half of that. If you take a living and dead plant, and expose them to the same atmosphere, you will find that the warmth of the living plant is somewhat greater than that of the dead one. More than this: you will find that in the leaves and young stems, as the parts in which the most active vital changes are taking place, the elevation of temperature is greatest. But to return to the animal economy. It cannot be denied that the variations of heat in man are dependent in part upon the temperature of the external air-on the general condition of the body, as to repose or activity-the period of the day-the time that has elapsed since the taking of a meal, and even on the quantity and quality of the food consumed in different seasons and in different climates. A larger amount of heat is generated during the day than in the night-the body is warmer at noon than at midnight. The temperature is raised during the process of digestion. The quantity of food consumed in colder seasons and in northern regions is different and greater than what is consumed in warmer suns and southern climes. It is this last fact which explains the preservation and continued activity of life within the frigid zones. The food adapted to the inhabitants of these cold regions-such as the several fatty and oily substances-abounds in carbon and hydrogen, and combining with the large quantities of oxygen derived from the lungs by breathing a cold dense air, a proportionate degree of heat is generated in the body. But has not the period of life to do with the maintaining of the heat of the body, and so with the continuation of life? Most certainly. Some young animals come into the world in such an advanced condition, as to be almost independent of parental assistance, and therefore capable of maintaining their own temperature; but when they are born in such a state as to require to be for some time supplied with food by the parent, they are then more or less dependent upon the warmth imparted to them from the parental body: This is especially the case with children, who are more dependent on the parent than the young of any other animal. However • Cold-blooded animals, among which are the Invertebræ, have little or no power of sustaining an independent temperature. They depend for their vital action upon the warmth they receive from the air or the water which they inhabit. They have no power of resisting the depressing influence of cold, and when the temperature sinks below a certain point, they pass into a state of complete inaction or torpidity. Their vitality falls with the dimi tion of their heat. An interesting question comes in here:-How do we know that the production of heat is modified by the influence of the nervous system? If animal heat is to be resolved into a chemical process, what can the nerves have to do with it? We can only appeal to facts. If the supply of nervous influence to any part of the body be cut off, the temperature of that part falls below its proper standard. For example :-it has been found that the temperature of the hand of a paralysed arm has been as low as seventy degrees, while that of the sound side had a temperature of ninety-two degrees. On electrifying the paralysed part, the temperature rose to seventy-seven degrees. In the finger of a paralysed hand, the temperature has been six degrees less than in that of a hand not paralysed. So we all know, that if we are very much depressed in our minds, how the temperature of our bodies falls, and we feel chilly and cold. On the contrary, if we become powerfully excited by passion, the heat of the body may increase even to perspiration. Yet we must not conclude that animal heat is generated by mere nervous action. All that we can say is, that nervous action in some way or other affects those chemical changes which are going on in the system, and to which, in an especial sense, we ascribe the generation of heat. the electric state of the bodies concerned, and hence we find that Nearly all chemical changes are attended with some alteration in some living animals exhibit the most marvellous manifestations of free electricity. The best examples are furnished in the TORPEDO, or ELECTRIC RAY, and the GYMNOTUS, or ELECTRIC EEL, both of which possess a set of organs in which electricity may be generated and laid up in large quantities, and from which it may be discharged at will. The delicate experiments made on both these species, prove that the shocks communicated by them are due to electric currents so generated in these electric organs; and that these organs owe their most immediate and powerful stimulus to the action of the nerves. Their nerves, which arise from the top of the spinal cord, are of very great size-larger than others in the same animals-and larger than any nerves in other animals of the same bulk. As a consequence, their shock is very powerful. The shock of a large gymnotus is sufficient to kill small animals, and even to paralyse men and horses! "In both species of fishes, the electricity generated by the action of their peculiarly organised batteries-besides its benumbing and stunning effects on living animals-renders the needle magnetic, decomposes chemical compounds, emits the spark, and, in short, exercises all the other known powers of the ordinary electricity developed in inorganic matter, or by the artificial apparatus of the laboratory." Animal and common electricity are one and the same. In the FROG, during its whole life, there is a continual current of electricity, passing from its extremities towards its head, termed le courant propre, or peculiar current of the frog, as it has been discovered in no other animal. 66 But are there any manifestations of electricity in man? There are some persons who have it in a remarkable degree, and of equal months in an electric state so different from that of surrounding power. A lady, called THE ELECTRICAL LADY, was for many bodies, that, whenever she was but slightly insulated by a carpet or other feebly-conducting medium, sparks passed between her person and any object which she approached. When she was most favourably circumstanced, four sparks per minute would pass between her finger and the brass ball of a stove, at a distance of one inch and a half." It is a not less curious fact that some of the lower animalsespecially the fish tribe-have the power of evolving light. You are familiar with that beautiful phenomenon called the phosphoresence 1. THE past definite may be called the narrative or historical tense of the French. It is used to express an action entirely past, definite and complete in itself. The time must be specified, and every portion of it must be elapsed. One night at least should have occurred since the action took place. Mon frère partit hier pour Paris. My brother left yesterday for Paris [Sect. 40] may be used for the past definite. The past definite, 2. The student will bear in mind that the past indefinite however, may never be used for the indefinite. In conversation the indefinite is often preferred to the definite, as the latter would at times appear too formal [§ 121 (3)] :— 3. The past definite may generally be rendered in English by the simple form of the imperfect, or by the same tense conjugated with did. The past definite can never be rendered in English, by the participle present of the verb preceded by was. Je Tu Il 4. TERMINATIONS OF THE PAST DEFINITE OF THE FOUR CONJUGATIONS. See Sect. 22, and § 60. Nous Vous Ils fournit furnished chant -ai spokest fin -is finished chér -is cherishedst gave gathered tend tended -it cherch -âmes sought carried pun -îmes déç -urent mord -irent 5. It will be seen that the terminations of the second and Several vegetable and animal substances are thus phosphorescent when deprived of vitality. By the spontaneous decay or decomposition of vegetable productions in stagnant water, there is formed a gas composed of carbon and hydrogen, which, when it is kindled, is probably the cause of the light that so frequently is seen during the evenings of summer and autumn, flickering and dancing over the surface of some marsh or boggy soil, and which is known by every schoolboy as JACK-O'-LANTERN, or WILL O'-THE WISP. A spontaneous pale light is known to be emitted from the decayed wood of old forest trees. And there are certain flowers, such as the tuberose, nasturtium and marigold, which occasionally present flashes of light towards the close of a warm summer's evening. In the animal economy, the flesh of the carp, tench, herring, sole, crab, and lobster, affords the most remarkable instance of this phenomenon of luminosity, but it is seldom presented by the dead flesh of quadrupeds, and never by that of birds, under any circumstances fourth conjugations are alike. of putrefaction. Although it is very rare in any of the higher vertebræ, and especially in man, yet instances have been recorded. It is fair to state, however, that the individuals exhibiting this luminosity, have suffered from some wasting disease, such as consumption, and were near the close of life, so that the light emitted is to be accounted for by the decomposition of the tissues. Here, however, is a striking case :-A large cancerous sore of the breast emitted so much light, as to enable the hands on a watch-dial to be distinctly seen when it was held within a few inches of the ulcer. There can be no doubt that, in this instance, the phosphorescence was owing to the decomposing and decaying surface of the wound being exposed to the oxygen of the air, as in the case of a dead body. What a world of mystery is man in himself! Whether we look at the structure and functions of his body, or go into the grander domain of his soul, we are perplexed and baffled. We can never hope to explain the phenomena of either matter or mind. And it will be among the lofty employments of a higher world to study the manifold works of God. QUESTIONS FOR EXAMINATION. What is the standard heat of the human body? How is the uniform temperature of our system produced? In what species of animals do we find the highest temperature? On what conditions is the temperature of the human body dependent? Can very young animals maintain an independent temperature? What is the difference between animal and common electricity? 1. Le banquier reçut il beaucoup d'argent la semaine dernière ? 2. Il en reçut beaucoup. 3. Aussitôt que vous aperçûtes votre frère, ne lui parlâtes vous pas ? 4. Dès que je I'aperçus, je lui parlai. 5. Avez vous déjà porté vos habillements neufs? 6. Je ne les ai pas encore portés. 7. Quand il remerciai et je le priai de vous remercier. 9. Avez vous trouvé vous donna de l'argent, hier, le remerciâtes vous? 8. Je le vos livres? 10. Je ne les ai pas encore trouvés. 11. Lorsque vous vintes nous voir ne finîtes vous pas vos affaires avec mon père? 12. Je les finis alors et je le payai. 13. N'avez vous pas vu votre sœur ainée pendant votre séjour à Lyon? 14. Je ne l'ai pas vue. 15. Ne vous couchâtes vous pas trop tôt hier LESSONS IN FRENCH. au soir? 16. Je me couchai tard. 17. A quelle heure vous voulut. EXERCISE 100. 1. What did you receive last week? 2. We received fifty francs from your friend, and twenty-five from your brother. 3. Did you take your son to church with you yesterday? 4. I did not take him there (y). 5. What did you lose last year? 6. We lost our money, our clothes, and our horses. 7. Have you looked (cherchés) for them? 8. I looked for them, but did not find them. 9. Did they speak of your brother yesterday? 10. They spoke of him and of you. 11. What did the physician give you? 12. He gave me nothing. 13. At what hour did your sister rise yesterday? 14. She rose at five o'clock. 15. Did you rise early this morning? 16. We rose at half-past 18. He has six. 17. Has your cousin sold all his property? not sold it, he has given it to his eldest sister. 19. Has the traveller related his adventures to you? 20. He related them to me. 21. Did that man try (cherché) to speak to your father? 22. He tried to speak to him. 23. Did the professor speak of your brother during his stay at your house? 24. He spoke of him. 25. Has your friend worn his new coat? 26. He has not worn it yet. 27. Have you thanked your brother? 28. I have thanked him. 29. What have you given to your eldest sister? 30. I have given her nothing, I have nothing to give her. 31. When your brother gave you a book last year, did you thank him? 32. I did not thank him. 33. Is it late? 34. It is not late, it is only six. 35. Is it fine weather or bad weather? 36. It is very fine weather. SECTION LI. Le pharmacien ne vint-il pas vous Did you not take your son to Spain last year? I took him there and left him there As soon as you saw your brother, did you not recognise him? I recognised him as soon as I per ceived him. Did not the apothecary come to see you? Il vint me voir; il fut bien étonné He came to see me; he was much de trouver chez moi, un de ses Ne prites-vous pas congé de vos amis, hier? Je pris congé d'eux, et jes les priai de m'écrire. Accompagner, 1. to accompany. A la fin, at last. sistance. astonished to find one of his old friends at my house. Did you not take leave of your friends yesterday? I took leave of them, and begged them to write to me. Congé, m. leave. 1. The terminations of the past definite of irregular verbs, are seldom arbitrary, but an irregular verb of one conjugation will sometimes, in this tense, assume the terminations of ano-hui ther conjugation. In a few instances the stem [Sect. 22] of the verb is entirely changed. LIRE, to read. 1 -us 1 -ut 1 -ûmes 1 -urent 2. Avoir and être, it will be perceived, take in this tense a new stem, e-us, f-us; être and lire, though belonging to the 4th conjugation, take the terminations of the 3rd, and voir, a verb of the 3rd, takes the terminations of the 4th. 3. In other instances, the stem of the verb drops some of its letters, and sometimes adopts others. This may be seen in the verbs CONDUIRE, to conduct. vinrent-ils hier vous prier de les accompagner? 16. Ils vinrent me voir, mais ils me quittèrent sans me parler de leur voyage, 17. No peignites-vous pas un tableau l'année dernière 18. Je peignis un tableau d'histoire. 19. Le peintre italien a-t-il fini son portrait? 20. Il le finit hier. 21. Il l'a fini ce matin. 22. Dès que j'eus reçu cette nouvelle, j'envoyai chercher le notaire. 23. Ce jeune homme a-t-il pris congé de son père. 24. Il a pris congé de lui. 25. Il prit congé de lui hier. EXERCISE 102. 1. Did the notary accompany you yesterday? 2. He accompanied me as far as (jusque chez) your brother's. 3. Did your companion take leave of you yesterday? 4. He took leave of me this morning. 5. Did you read yesterday, the book which I have lent you? 6. I read it the day before yesterday (avant hier). 7. At what time did the painter come this morning? 8. He came at half-past nine. 9. Has he finished your father's portrait? 10. He painted all day yesterday, but the portrait is not yet finished. 11. Did you not run to your father's relief when you saw him in danger? 12. I hastened to succour him. 13. What did you do when you came? 14. As soon as I came I sent for my brother. 15. Did you take your sister 16. I took her there this year. 17. to Germany last year? Did you take your children to school yesterday? 18. I took them to my brother's. 19. Do you paint an historical picture? 20. I painted last year an historical picture. 21. Did your sister beg you to accompany her? 22. She begged me to accompany her. 23. Did you send for the notary as soon as you heard from your father? 24. I sent for him. 25. When did the notary take leave of you? 26. He took leave of me this 29. Were you not astonished morning at nine. 27. Has the apothecary finished his letter? 28. He has not yet finished it. yesterday to see that lady? 30. I was not astonished to see her. 31. Did you make haste to read your book last night This termination is arbitrary only in verbs ending in enir in which hier au soir)? 32. I made haste to read it. 33. Have you ann comes after the i of the termination: víames, tinmos, &c. Nous vinmes primes conduis -is conduis -is conduis -it conn -ûmes conduis -fmes craign -îmes Vous v-intes conn -ûtes conduis -îtes pr -îtes craign -îtes Ils v-inrent prirent craign -irent conn -urent conduis -irent 4. Like venir, are conjugated all verbs ending in enir; like craindre, connaître, and conduire, those ending in indre, aître, and uire; and like prendre, those composed of this verb and a prefix; as, comprendre, surprendre, &c. 5. We would at all times refer the student to the table of irregular verbs, § 62, for those tenses of the irregular verbs with which he is not familiar. finished it? 34. I have not yet finished it. LESSONS IN GEOLOGY.-No. XIII. ON THE ACTION OF VOLCANOES ON THE EARTH'S CRUST. ON THE ELEVATION AND SUBSIDENCE OF LAND (continued). In our last lesson, the elevation and depression of land by the action of earthquakes was considered. Earthquakes produce these changes in the level of the surface, by effecting a separation of enormous masses of ground from each other by means of faults, fissures, or slips, and then causing some of these portions to rise to a higher elevation, and occasioning others to sink to a lower level. Geological inquiries, however, furnish us with many instances of elevation and depression of land, which the action of earthquakes will not explain. To give sufficient distinctness to these two classes of phenomena, I have divided this section into two parts. The first part treated of elevation and subsidence of land by earthquake power; the second part will show how these changes in the level of land and sea have taken place without that agency. §ii. Elevation and subsidence of land without earthquakes. Whenever the surface of the land is raised above its usual elevation, it must be either by a force from below rending great masses of the earth's crust by means of fissures and faults, and then propelling them suddenly upwards; or by the expansion of subterranean matter lying deep in the interior of the earth. Science has not discovered anything that could produce sufficient expansion to effect this, but subterranean heat. If the temperature of subterranean rocks becomes increased the heated rocks will expand and swell out, and thus raise the strata that rest upon them. If this heat diminish again the interior rocks will contract, and the incumbent beds will sink and subside. It is scarcely necessary to prove to you that heat expands a body. Take any bar of iron, your own poker for instance; put it first in any orifice, opening, or hole which it just fits; place it then in the fire till it become heated into good red-heat. If now you try to put it in the same orifice or hole, you find that it will not enter. Why? It is because the fire has expanded and enlarged it. subject to earthquakes, or to volcanic power, in any violent form. Of these changes, instances are numerous,-in the rise and depression of land which are taking place at the present day,in the submarine forests which have been submerged in centuries comparatively recent, and in ancient sea-beaches which are now found at a high elevation. I. THE RISE OF THE COAST OF SWEDEN AND NORWAY.-In our own day, an immense tract of land, about a thousand miles in length, and fifty or sixty in breadth, situated on the northern shores of the Baltic Sea, has been rising for many years, and is still rising. Take a map of the north of Europe, which you can now buy for a penny, and mark the area of this phenomenon. From Gottenburg to Torneo, and thence to the North Cape, the whole country, with its towns and people, has already risen from 100 to 200 feet above the level of the sea, in times apparently very modern. It has been ascertained that this elevation goes on at the rate of about four feet in every century. What is remarkable is, that the rising is not uniform; but advances at different rates in different districts. This is probably owing to the diversity of expansion, which takes place in different localities, of the rocks which are heated beneath. This change of level was asserted by CELSIUS, in the last century, and ascribed by that philosopher to the retirement of the sea. This common supposition is contradicted by the fact that, while the waters of the sea retire and appear to sink at Torneo, in the northeast of the Baltic, they maintain their former level at Copenhagen, to the north-west of that basin or gulf. That the difference of this change of level is due to the rising of the earth, and not to the sinking of the water, was asserted first by the Scottish Geologist, Playfair. He showed that, to sink or to raise the absolute level of the sea by any given quantity in any given place, there must, from the laws of Hydrostatics, be a corresponding depression or rise of the same quantity over the whole surface of the earth. The reality of the elevation of so large a district was long doubted. The German Geologist, Von Buch, in 1807, after a personal examination of the facts, was the first to declare that the change was due to the elevation of the land. He was convinced that the whole country, from Frederickshall in Norway, to Abo in Finland, and perhaps as far as Petersburg in Russia, was slowly and insensibly rising. This question has been set at rest by our countryman Sir Charles Lyell. He has visited this district on two different occasions, for the express purpose of settling this matter to the satisfaction of all scientific men. In his survey, he examined the shores of the Gulf of Bothnia from Stockholm to Gefle, and then the western coast of Sweden about Gothenburg and Uddevalla, and found that everywhere the coast was higher than certain before his visit, and very much higher than the indications which Celsius had pointed out in the preceding century. Heat produces the same effect in stone; yet all stones do not expand alike when heated. An American geologist has made very cautious and accurate experiments upon the capacities of different stones, such as granite, crystalline marble, and sandstone, under the influence of increased temperature. These experiments, conducted with mathematical precision, have shown that if a portion of the earth's crust, ten miles deep or thick, were to be heated to the degree of 600 Fahr., the expan-marks which pilots had made on the rocks some twenty years sion of the subterranean rocks would cause the surface to rise two hundred feet above its former level. They have also shown that a greater thickness than a series of ten miles deep might be heated, provided any new focus of heat should be produced at any given spot in the interior of the earth. You will at once perceive that if this intense heat becomes dissipated by radiation, the swelled rocks below will contract and become of smaller dimensions; and, by consequence, the strata resting on them will again subside in proportion to the diminished temperature below. This theory of the expansion and contraction of rocks at great depths, in connexion with a philosophical allowance of sufficient geological time, will account for all the elevations and dislocations which are found in continents and in mountain chains. Still it is right to state to you that this theory is not without its difficulties. The several systems of elevation, which are found in the same continents, and the numerous examples of strata tilted up and thrown into a vertical position, seem to require some other hypothesis to account for them. There are also, in the north of England, instances of elevation which were accompanied by prodigious dislocations of rocks; and these elevations, being to the extent of several thousand feet in height, seem to have been produced by a single paroxysm of earthquake power. These circumstances will be examined in a future chapter on the architecture of rocks in the crust of the earth. It is well known that changes in the level of land and sea have taken place in districts, which are not known to have been The evidence of this elevation is most satisfactory. You are, perhaps, aware that there are shellfish, some of which live only in the waters of the ocean, and others which live only in the salt water of inland seas, and gulfs, &c. Now, near Uddevalla, on the western coast of Sweden, which borders on the Atlantic Ocean, there are elevated deposits of shells belonging to species now living in that ocean; while on the eastern coast, about places bordering on the Gulf of Bothnia, there are upraised beds containing the shells of species characteristic of the Baltic Sea. Very numerous, and a copious variety of proofs of this elevation, are enumerated by Sir C. LYELL in his work on the Principles of Geology. Though it is capable of demonstration that this extensive district is now rising out of the sea, there are proofs, as abundant and as satisfactory, that in some earlier centuries it was sinking instead of rising. This shows to you that there may be an alternate depression and elevation of the same surface taking place, corresponding to the increase or diminution of the expansive forces in the mineral regions below. In digging a canal to the south of Stockholm, in 1819, the excavators came to marine strata, that is, beds deposited by the sea, and containing fossil shells of the same fish which are now peculiar to the Baltic. This proves, that at one time, the district had been covered by the Baltic Sea. In the excavation of this canal a deep cutting had to be made, about sixty feet in depth. When the workmen came to this depth they |