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which is wrapped about the seed much more closely. On one side of the grain a groove may be observed; and at the base on the opposite side, a small oval lump, which shows the germ of the future plant. The vessels by which the grain was attached to the plant, and through which it drew support until its maturity, were at the lowest end of this protuberance. When the seed is perfectly ripe, these vessels separate, the point of separation speedily heals, the grain may then be easily threshed out from the chaff in which it had been buried, and sometimes it sheds itself spontaneously. Wheat is very widely diffused. It flourishes not only in our temperate clime, but also in the extremes of heat and cold. In Lapland it is cultivated as far as sixtyeight or seventy degrees north latitude; and Humboldt found, in the neighbourhood of La Victoria, at the height of more than 2,000 feet above the ocean, some fields of wheat, mingled with plantations of coffee, plantains, and sugar-canes." Thus, as it is the plant most necessary to mankind, so it is the most eneral; while its presence - in any region of the earth, Germination of plants. attests the civilisation of luán. In the sepulchres of the Egyptian kings, for example, the common wheat was found in vessels so perfectly closed, that the grains retained their form and colour; and as the cornplants do not grow wild in any part of the earth, and appear

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Fig. 5.

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Barley is grown to almost as great an extent as wheat; more particularly in the East, as in Egypt and Syria, where it forms the staple grain for making bread. It wants, indeed, the substance called gluten, which appears peculiar to wheat, and makes flower form so good a paste, and which is essential in rendering fermented bread light. But in the East, barley is chiefly used for unleavened bread, in the form of thin cakes, so common among the peasantry of Scotland, and not unpalatable to those accustomed to its use. Pearl barley is the same vegetable, only freed from the husk by a mill. Barley-water, a decoction of pearl barley, is a valuable beverage. In the engraving, fig. 6, A represents the common kind, and B the fan barley.

The seeds of a corn plant are sometimes placed on a single rib or rachis, as in wheat and barley, and they then form a spike. In what is called Egyptian wheat this spike is compound, there being more than one rib, and if this consists of branches that are naked at their points of junction, and have spikelets at their extremities, they form a panicle; such, for example, is the case with oats. Oats will grow in soils which will not bear wheat or barley, and in situations not adapted to other grain. In the mountainous parts of Scotland, and the hilly districts of Derbyshire, it is almost the only grain cultivated. The ear of the oats blade has two forms, which are represented in the engraving, fig. 7. While young and light.

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the branches arrange themselves round the centre of the stem.; but as they advance towards maturity, and acquire weight, they generally bend over on one side. Thus, a beautiful provision is made for the health of the plant. For now the air, and light can visit it freely, and the rain may wash every individual grain, and preserve it from the seeds of any destructive plants. And then, as the grains are pendent and have the open extremities of the chaff towards the earth, they are effectuall defended from the lodgmentofrain within-an advantage which neither wheat nor barley possesses, and hence are liable to diseases from which oats are exempted. Such, then, is a brief description of some of the cultivated grasses, which have become so familiar, and so valuable as corn; and we may conclude the present lesson with an interesting and instructive anecdote related by Pliny. Cresinus, a Roman, was cited before an assembly of his people, on a charge of sorcery, from his reaping much larger crops than others from a small piece of ground. In answer, to the charge;

Cresinus produced his implements of husbandry, his well-fed oxen, and a hale young woman, his daughter, and pointing to he exclaimed, "These, Romans, are my instruments of

witchcraft; but I cannot here show you my labours, sweats,

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--> *-rix-scores.” A-3 so it is in many other instanees.' 2. Find the prejects of the number 9ssos, by all the numbers We see : e res---, it may be with pleasure or astonishment, from 11 to #9 inclusive, and the answers will be found in the table * ----esk: ; –the to that secured it, is hidden from our view. given in Exercise 6 page 5°. No. 1 W. Le: -s re-ember, towever, that nothinz valuable is gained 3. 7050.8 x 70508 ; 1010101 x 20202; 99999>{999 : ------ efort, and that labour, wisely directed and persever- 14-8571428.57x7777. ingly employed, will achieve what many would regard as . When the factors have insignificant figures in both; or, in other ---------7 i-possite. words when the multiphered and multiplerbeth terminate in any mus ber of ciphers, proceed according to the following rule:— Rule so the significant figures of the factors as directed in Rule 4. Then, to the product annex as many ciphers as are |annexed, both to the multiplier and the multiplicand; that is, to ofors. Soo-oo-o-ters to so stors are: = then proceed accordinz to the following rule. to it, then arres only as of as are found annexed to the other *::::::=o: the : the o: under those of the 'f-etor. The Frisirls of this =neration of ciphers has alread multiplicand. in addition or subtraction, so that units shall be been explained under Rule 3. under units, tens under tens, &c., and draw a line under it as be-1 Examiris I.-Multiply 40758:

and

LESSONS IN ARITHMETIC.—No. VII.
RTLE OF SIMPLE XIULTIPLICATION.—Confinued.
Wass the multiplier and multiplicand consist of several significant

fore. Then, multiply all the figures of the multiplicand by the Factors {{: at i + o-
raits' figure of the multiplier, and place the product under the - *- So
line, as directed in Rule l; next, multiply all the figures of the
multiplicand by the tens' figure of the multiplier according to o
- *

Rule 1, and place their product under the former, taking care to observe that as it is the product of tens, a cipher either expressed or understood should stand under the units of the preceding product, then the tens under the tens, the hundreds under - - the hundreds, &c. Again, multiply all the figures of the multipli- offs to this.ors =so be so. because 100x cand by the hundreds' figure of the multiplier according to Rule 1. lovo-loo); and 123157.75x lo–123157.7600000. and place this product under the preceding one, observing th: ciphers, either expressed or understood, should stand under the units and tens of that product, then the hundreds under tile - ------ ----hundreds, the thousands under the thousands, &c., as before. 2. Mekirly Iososo occo. Pro in oes===ser, saltiplying oil the soures of to 3. Sooooooooooxicoidoo-oooo. :::::::::::::::::: ::::::::::::::::::::::: Pacor or Mriri Plucariox.

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Ezracises. 1. Multiply 10101001000 by 100:01.000.

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Generally speaking, the best proof of multiplication is to reverse the position of the factors: that is, to make the multiplier the multiplicaad, and the multiplicand the multiplier. As this process, ; however, would be both awkward and tedious in some cases, especially inits application to Rules 1, 2, and 3, a proof founded on the principle of Rule 4.—viz., that the product of two numbers is equal to the sum of the products of tie one number by the several parts of the other muzber, is to be preferred. We proceed to show the application of this principle to rules 1.2, and 3.

Taking the first example in Rüssel, we find that the multiplier8 is composed of two parts, say 5 ord 3: then, multiplying the multiplicand separately by each cf these parts, and adding the partial products, we shall have the same result as if we multiplied

by S. Thus:—

Multiplicani $2788 Multiplicani 3.2768 is: Eartial irlier 5 2nd partial multiplier 3 1st partial product l63840 2nd partial product 98.304

| Now taking these partial products and adding them together as follows, we have the complete product; thus:–

1st partial product 163S40
tad partial product &S394
Comple:e product 26-144 -

As this product agrees with the former (page 94, No. VI.), the

Proof must be considered complete.
Again, taking the first example in rule 3, we find that the multi-

For 900 is composed of 400 and 500; then, multiplying the

multiplican; separately by each of these parts and adding them as

o: we shall have the same result as if we multiplied by 900. -> -

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Besides various other uses to which this table may be applied, we shall point out four of considerable importance to the trading community. The vertical (upright) or horizontal (from side to side) column containing the products of 12 by all the numbers from 1 to 20, will be an excellent substitute for a pence table. If we take the vertical column of the products of 12, then the number of shillings, answering to any number of pence in this column, will be found in the first vertical column, on the left hand. Thus, if you wish to know how many shillings are in 204 pence, look down the column having 12 at the top, for the number 204, and in the same horizontal line with it, on the left, in the first vertical column, stands 27, the number of shillings.

The column containing the products of 20, by all the numbers from 1 to 30, will be a substitute for a shillings’ table. If we take the vertical column of the products of 20, then the number of pounds, answering to any number of shillings in this column, will

be found in the first vertical column, on the left hand. Thus, if
you wish to know how many pounds are in 340 shillings, look
down the column having 20 at the top, for the number 340, and
in the same horizontal with it, on the left, in the first vertical
column, stands 17, the number of pounds.
The column containing the products of 16 by all the numbers
from 1 to 20, will be an ounces' table. If we take the vertical
column of the products of 16, then the number of pounds (weight),
answering to any number of ounces (avoirdupois) in this column,
will be found in the first vertical column on the left hand. Thus
if you wish to know how many pounds are in 224 ounces, look
down the column having 16 at the top, for the number 224, and in
the same horizontal line with it, on the left, in the first vertical
column, stands 14, the number of pounds (weight).
Lastly, the column containing the products of 14 by all the
numbers from 1 to 20, will be a pounds’ table for stones. If we

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take the vertical column of the products of 14, then the number of stones (weight) answering to any number of pounds in this column, will be found in the first vertical column on the left hand. Thus, if you wish to know how many stones are in 238 pounds, look down the column having 14 at the top for the number 238, and in the same horizontal line with it, on the left, in the first vertical column stands 17, the number of stones. DeriNITIon.—When a number is multiplied by itself, the product is called the square of the number. Thus, when we say 9 times 9 are 81, the number 81 is called the square of 9. The name square is borrowed from applied geometry, because in finding the area of a square, the length of whose side is given, we multiply this length, given in numbers, by itself, and the product is the area. Thus, if the side of a square was 6 feet long, the area of the square would be 36 square feet; because 6x6 = 36. The table given above contains, diagonally (that is from corner to corner) from the blank corner to 400, in the last square on the right, the squares of all the numbers from 1 to 20. The square of any number is found at the place where the vertical and horizontal columns, that contain the number, meet. Thus, the square of 12 is found by running the eye down the column having 12 at the top, till it come to the horizontal column having 12 at the beginning. The square of 12 is thus found in the table to be 144.

LESSONS IN PHYSIOLOGY..—No. IV.

M A N.

We take, for granted, that you now understand the theory of THE CIRCULATION of THE BLooD. Plants have no blood, but they have a circulation. In the leaf, the ascending sap undergoes such an elaboration or preparation as adapts it to the nourishment and growth of the plant; and from the leaf, there is a network of small vessels, which runs along the branches of the stem and roots, and by which the sap is thus conveyed to every part, till it is all but entirely exhausted by the dif. ferent tissues through which it has circulated, taking up into themselves all its nutritive matter. The only condition necessary for the life and increase of the lowest plants, is, that they be in immediate contact with the two elements of air and water. Their whole substance is nourished by means of the fluid which surrounds them. Take, for example, the seaweel-every part of its soft external surface being equally in contact with the water, every part of the weed takes from the surrounding fluid, and assimilates whatever is suited to itself. It is only, as we ascend the scale of animal life, that we find provision made for circulation; and this provision may consist of a single vessel, with the power of contracting and sending forward the fluid which it contains through all the vessels that issue from it, as in the star-Fish, up to the complex and wonderful structure and apparatus of the human heart.

The human body is made up of an assemblage of countless cells; but the arrangement and disposition of these cells is such, that they cannot all come into immediate contact with the influences of the external world, as in the case of a simple plant. Between the external world, however, and these cells, there comes the nutritive and vital fluid of the blood, which goes to every individual part of the body, and which, in its circulation, represents two distinct currents. One current conveys to the cells the material of nutrition and secretion; and the other current carries away from these cells the materials of absorption. The vessels or tubes, in which these currents are performed, are called the arteries and the veins. The arteries convey the bloodin its pure and vital condition to every part of the system, and the veins take it up in a degenerated state, and carry it back to the heart and lungs, to come in contact with the air in the organs of respiration; while the absorbents are small, delicate, transparent vessels, which take up from the surface of the body, or from any cavity, those portions of nutritive matter which are not in a state of perfect solution, and which, by passing through the thoracic duct, or the passage which lies in the front of the spine, between the chest and the belly, is prepared for entering into the current of the blood. These little vessels are called LACTEALs, from the Iatin word LAC, which signifies milk, because of the milklike appearance of the fluid ; or LYMPHAT1cs, because they so the lymph or superfluous moisture which is found in the

ody.

In a chemical point of view, the blood represents the whole body in a liquid state, since the blood contains all the elements which enter into the human frame, and which are combined in the form of albumen, febrine, colouring matter, fat, and salts, It is owing to this composition that the blood is fitted to furnish the materials of growth and increase to every individual part. But while it furnishes the materials of nutrition to every part of the body, it sustains itself a positive loss; and this loss must be continually made up, otherwise the blood will no longer be fitted to minister to the nutrition of a single part. If every tissue in the body is taking from the blood that which is adapted to support and preserve itself, then we must restore to the blood that which it has lost. This we do by the food which we eat, and the air which we breathe.

If the loss which the blood sustains is to be made up by our taking food, then the food itself must undergo certain changes. The first change takes place in the mouth. Why has the great Creator furnished the mouth with two rows of teeth? Though essential to beauty, they were given not for ornament only, but for use. Most articles of food require to be masticated or chewed. And for this a beautiful provision has been made in the teeth, of which we have sixteen in each jaw. Four of these are placed in the front, and are called INcisors, from their power of cutting or dividing the food; two are named cANINE or doglike teeth; and the other ten are known as molars or grinders.

In the act of chewing, the food becomes mixed with the saliva of the mouth, which partakes of an alkalipe, and so reduces it into a kind of pulp. Till it is so reduced, it is not in a fit state to pass into the stomach. In the stomach the gastric juice should have access to every particle of matter that passes into it; but this is impossible unless there be a thorough admixture of the food and the saliva in the mouth. Persons who eat fast never sufficiently chew their food; being imperfectly chewed it never becomes thoroughly mixed with the saliva : and passing into the stomach in this state, it never digests as it ought, and hence such persons are doomed to suffer all the horrors which arise from indigestion. The mouth into which the food is received is lined with a beautiful thin membrane or covering, which extends backwards, and terminates in a common tube or funnel, which is called the PHARYNx. The pharynx is divided into prolonged tubes, one of which descending from the pharynx is called the GEsoph Agus, or commencement of the digestive canal; while the other, which is situated in the pharynx and named the LARYNx AND TRACHEA, is the passage to the lungs or respiratory organs The digestive canal traverses the chest, developes itself in the bowels, terminates in the anus, and in its whole course represents a tube whose superior opening is the mouth. Although the quantity of saliya formed in the mouth during four-and-twenty hours is from fifteen to twenty ounces, yet its flow takes place only as it is wanted, or as food is taken into the mouth, and the work of mastication goes on. But if you are hungry, and pass the kitchen during the process of cooking, or go into a room in which a nice dinner is being served, or even let your mind be directed to some favourite dish, there will be an instant flow of saliva, or to use the common phrase —a watering of the mouth. The food being prepared by the mouth, this is followed by the act of swallowing. The pulp passes from the mouth into the Gesophagus, which descends from the pharynx into the stomach. The stomach, of which the annexed engraving is but a simple and imperfect representation, is the grand receptacle for the food, and in which it comes into immediate contact with the GAstBIc JUICE. While the saliva is alkaline, this juice is acid, and is poured forth from the walls of the stomach on every successive introduction of food. The presence of food is necessary to excite this sluid, and hence it is never detected in the empty stomach. Its flow may be increased by taking a small quantity of salt, pepper, mustard, or any other stimulating substance that can affect the mucous membrane. But stimulants taken in excess are injurious, as they retard the process of digestion. So is the introduction of any superfluous

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A The inner surface. B. The Cardiac orifice. c The CEsophagus, or passage into the stomach. D. The Pyloric orifice. E. The intestine, or passage out of the stomach.

article into the stomach. So is the habit of taking more food than the system requires. So is the error of not allowing a sufficiently long interval between our meals. So is the practice of o: too much cold liquid. . Digestion requires a temperature of about one hundred degrees, but if we fill the stomach with cold water or with ice, we reduce the power of digestion, and delay the process. All these errors should be carefully avoided. Never forget that it takes from three to five hours to perfect the work of digestion, and that in every instance, it is our duty to sacrifice taste to health. The food being subjected to the action of the gastric juice, is gradually transformed into a greyish pap, something like gruel, and to which is given the name of cHYME. This is a purely chemical change, corresponding in some degree to fermentation, and during which, the alimentary substances in the stomach so completely lose their form and colour, and become so modified in their chemical nature, that it is no longer

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liquids—the bile and the pancreatic juice. The PANCREAs is a flat roundish gland, in form like the tongue of a dog, situated behind the stomach, and secretes a liquid resembling saliva in its appearance and chemical *. and whose use seems to be to dilute the chyme, and to incorporate it with the bile, so as to produce the chemical changes necessary for the formation of cHYLE. The secretion of bile, is, therefore, a process of the highest importance in the human economy. Of this we feel sure from the size of the liver, and the large supply of blood which it receives. Though we are comparatively ignorant of the chemical action of the bile upon the chyme, it cannot be denied that the bile itself serves the most useful and beneficial purposes in the process of digestion. Among these uses, we may name the following:— It renders more soluble the fatty matter that enters into most of our food. It takes from the chyme a certain portion of its acidity, if its acid be in the extreme. -- It gives to the chyme its colouring matter, and a resinous substance designed to prevent its decomposition. It partly excites in the intestine those movements which determine the progress of the chyme along the whole length of the intestinal canal. Its flow into the intestine is favoured by the presence of chyme; but, if that flow is obstructed, all the digestive processes" become disordered. It therefore aids digestion. The action of the liver is constant; but when the bile is not wanted in the intestine, it accumulates in the gall-bladder, which opens and gives out its contents when needed, and meets the chyme as it passes from the stomach to the duodenum. It withdraws from the blood certain products in a state of decomposition, and , which would prove highly injurious to the whole system, Independently of the pancreatic juice and, the bile, which are poured into the intestine, there is formed, in the surface of this canal, a liquid, which is called the INTESTINAL JUICE, similar in its nature, source, and uses, to the gastric fluid, whose action it supplements and completes. [A. The arch of the Aorta. B The Thoracic Aorta. C. The Abdominal Aorta and Branches. D The left Subclavian Wein. E. E. The junction of the internal Jugular and Subclavian Vein at each side. F. The Receptaculum Chyli. G. The Thoracic Duct.] The process of digestion being thus advanced, there are, on the walls of the intestines, what are called Absorbent vessels, which #. withdraw the nutritious portion from the contents of the intestine, and this is carried by the circulating current into the most remote tissues of the body. These absorbent vessels are called LACTEALs, on account of the milky appearance of the fluid which is formed in them. This fluid is the chyle, and these vessels, in their course form larger trunks, which converge and pour their contents into a cavity, known by the name of the Receptaculum. Chyli, or chyle-receptacle, which arises in the front and lower part of the spine. Into the same cavity are poured the contents of another system of vessels, which, from the transparency of their fluid or lymph, is called the LYMPHATIc system, which, in its general design and end, is very closel allied to the lacteals. In the Thor:Acic duct or cANAL, whic passes upwards in front of the spine, from the belly into the

THE COURSE AND TERMINATIQOF THE THORACIC DUCT.

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