Imágenes de página

form of a wedge. These leaves take a contrary direction to that of the root: they seek a passage upward; which having obtained, they lay aside their wedge-like form, and spread themselves in a horizontal direction, as being the best adapted for receiving the rains and dew. The radicle, every hour increasing in size and vigour, pushes itself deeper into the earth, from which it now draws some nutritive particles. At the same time the leaves of the germ, being of a succulent nature, assist the plant by attracting from the atmosphere such particles as the tender vessels are fit to convey. These particles, however, are of a watery kind, and have not in their own nature a sufficiency of nutriment for the increasing plant.

3. Vegetables, as well as animals, during their tender state, require a large share of balmy nourishment. As soon as an animal is brought to life, the milk of its mother is supplied in a liberal stream ; and the tender vegetable lives upon a similar fluid, though differently supplied. For its use the farinaceous lobes are melted down into a milky juice, which is conveyed to the plant by means of innumerable small vessels which are spread through the substance of the lobes; and which, uniting into one common trunk, enter the body of the germ, and thus supply that balmy liquor, without which the plant must inevitably have perished, its root being then too small to absorb a sufficiency of food, and its body too weak to assimilate it into nourishment. Thus admirable and well contrived is the method of Providence in supporting the plant in its earliest and tenderest stages! As the plant increases in size, the balmy juice diminishes, till at last it is quite exhausted. The trunk of small vessels then dries up, and the external covering of the seed appears connected with the root in the form of a shriveled bag.


LESSON 137. - Memoriter.

[ocr errors]

381. PRODUCTIONS OF NATURE. RULE. - For Scientific purposes. a minute analysis of the various parts of the object will, in general, be requisite; but, for a popular description, such a selection only may be given as shall render the whole interesting and instructive to general readers.

382. 1. Read the following Extract two or three times over, noticing the sequence of the sentences.

2. Reproduce the Example from recollection.

3. Institute a Comparison between your own and the original, when all deviations either in construction, punctuation, or sequence must be noticed.

[blocks in formation]

1. Lime, after it has been freed from extraneous matters by burning, is a mineral of a whitish colour, and pungent, acrid, and caustic taste, which changes vegetable blue colours to green, and corrodes and destroys animal substances. The process of purifying lime is by placing it in a large kind of furnace called a kiln, where the limestones and fuel are heaped in alternate layers. After having gone through this process it is commonly known by the name of quicklime. The principal use of lime is in the formation of mortar or cement for buildings. For this purpose it is first slaked by having water poured upon it ; a violent heat is thereby excited, and the lime falls into powder ; it is then formed into paste by working it with water and sand.

2. It is also used for agricultural purposes, being supposed, when laid upon land, to hasten the dissolution and putrefaction of all kinds of animal and vegetable substances, and to impart to it a power of retaining the moisture which is necessary for the vigorous growth of agricultural produce. It is employed likewise in the refining of sugar, in the manufacture of soap, in the melting of iron, and by tanners, in a state of solution, for dissolving the gelatinous parts of skins, and rer:oving the

hair from them. If swallowed or inhaled, it is a violent poison. Chalk is a yellowish kind of limestone well known. Marble is a close-grained species of the same mineral, so hard as to admit of being polished.

CLAY-SLATE. Clay-slate is a well-known mineral, of a foliated texture, and of a grayish, black, brown, green, or bluish colour. It breaks into splinters, and is nearly thrice as heavy as water. Its principal use is for the roofing of houses. For this purpose it is split into thin plates or laminæ, which are fastened to the rafters by pegs driven through them, and made to lap over each other at the edges in such a manner as to exclude moisture. Dark coloured and compact slates are manufactured into writing slates. In the preparation of these, the slate, after it is split of a proper thickness, is first smoothed with an iron instrument, then ground with sandstone, and slightly polished with tripoli (a clay of a yellowish-gray colour, which received its name from having been first imported into Europe from Tripoli), and, lastly, rubbed with charcoal powder. The pencils which are used for writing on slates are made of a particular kind of soft slate, which, on splitting, falls into long splintery fragments. When sufficiently solid for the purpose, slate is cut into inkstands, and turned into vases and fancy articles of various kinds.

LESSON 138. - Hints. 384. From the following Hints, which are given in regular succession, produce a Description, developed and expressed as nearly as possible in accordance with the rule:

385, Wheat. Bran, 1. Wheat, originally into Europe from Asia, well known, civilized countries world. 2. No grain so nutritive valuable

inhabitants all climates ; by wonderful ordination of Providence, capable sustaining without injury extremes heat cold. 3. Not only ripen in Egypt and Barbary, but equally well Scotland, Denmark, and Sweden. 4. Constitutes chief food British nation; and its abundance or scarcity regulates great degree welfare prosperity inhabitants,

5. For cultivation important grain best lands are rich clays heavy loam : although light soils produce wheat excellent, yet crops on other soils far most abundant.

6. Best season sced to the ground September, and earlier in month better. 7. Some farmers consider necessary steep the seed brine pickle before used, prevent it devoured by vermin, and render corn less to disease than without this process. 8. In good season wheat harvest commences August, finished ensuing month. 9. This corn usually cut reaping hooks, some parts mown with scythes.

10. Wheat liable injury, not only attack of insects, but several kinds disease, principal blight, mildew, smut. 11. In first the fibres leaves of the plants contracted enfeebled, grain ultimately deprived sufficient nourishment ; by mildew, straw and ear effected ; by smut the grains, instead of containing proper substance, filled black dark powder. 12. This ascertained to be fungus.

13. Mr. Edlin obtained from one pound avoirdupois of wheat, twelve ounces starch, twelve drachms of gluten, four drachms of sugar, the rest bran and waste. table used for sustenance of man contains gluten in so large quantity as wheat ; remarkable that gluten has near alliance to animal substance called albumen.

15. Bran husk of wheat separated in grinding. 16. Infusions of bran are not unfrequently employed externally internally medicine. 17. Sometimes hands instead soap. 18. In times scarcity, bran employed making household bread, effects on various constitutions not warrant general use, liable to bring on relaxed state of bowels.

14. No vege

LESSON 139. Oriyinal. 386. From the following subjects the pupil may select two or three for Description according to the preceding rules and examples, and written from his own observations:

1. A description of the Aurora Borealis ; or Milky Way; or Harvest Moon.

2. A description of the Tides ; or Rain ; or Snow.

3. A description of the phenomena of January; or April; or August.

4. A description of the advantages of a variety of Seasons.

5. A description of circulation of Sap in the trees; budding of trees,

6. A description of Distribution of Seeds.



[ocr errors]

387. Descriptions of Animated Nature may be regarded under two principal heads, — the Scientific and the Popular.

388. Requisites. Minute obseryation, extensive research, and great anatomical skill, are requisite for forming a profound Naturalist. A whole life might be spent in becoming such a character.

389. RULE. — A Scientific description comprises an enumeration of the generic and specific pro. perties, the form, colour, food, habits, &c. by which an animal is distinguished from every other. 390. RULE for a Popular description. - The

[ocr errors]
« AnteriorContinuar »