mer and winter wheat-the limits of which, both polar and equatorial, must differ somewhat; but this difference is not ascertained, because travellers, and even botanists, seldom allude to the distinction. Wheat is cultivated in Scotland to the vicinity of Inverness, (lat 58°;) in Norway to Drontheim, (lat. 64°;) in Sweden to the parallel of lat. 62°; in western Russia to the environs of St Petersburg, (lat. 60° 15′;) while in central Russia, the polar limits of cultivation appear to coincide with the parallel of 59° or 60°. Wheat is here almost an exclusive cultivation, especially in a zone which is limited between the latitudes of Tchernigov, lat. 51° and Ecaterinoslav, lat. 48°. In America the polar limits of wheat are not known, on account of the absence of cultivation in the northern regions. The physical conditions of these limits are, in the different countries where cultivation has been carried to the utmost extent, as follows:

Mean temperature, Fahr. Lat. Year. Winter. Summer. 350 57° 25 25

OTT

64

40

Scotland, (Ross-shire,) 58° 460
Norway, (Drontheim,)
Sweden,

62

40

Russia, (St Petersburg,) 6015'38

16

59

59

61

This table shows how little influence winter cold has in arresting the progress of agriculture towards the north; and this is confirmed in the interior of Russia, where Moscow is much within the limits of wheat, although its mean winter temperature is (according to Schonw) 53° 2′. The spring-sown wheat escapes the cold of winter, and wheat sown in autumn is protected during winter by a thick covering of snow. The farther in advance to the north, the more deep and enduring is the covering. The temperature of air, during the severe season, can therefore have no direct action on plants which are annual, or at least herbaceous, and buried under the snow. The isothermal curve of 57° 2′, which appears to be the minimum temperature requisite for the cultivation of wheat, passes in North America through the uninhabited regions of Canada. At Cumberland House, which is situated in the middle of the continent of North America, in lat. 54° N., long. 102° 20′ W., the officers of the Hudson's Bay Company have established a prosperous agriculture. Captain Franklin found fields of barley, wheat, and even maize, (Indian corn,) growing here, notwithstanding the extraordinary severity of the winter. The polar limits of the cultivation of wheat is the more important, since, during a part of their course, they coincide with the northern limits of those fruit trees which yield cider; and in some parts also with the limits of the oak. Agriculture and forests, therefore, both undergo a sudden and remarkable change of appearance on approaching the isothere of 57° 2. In middle and western Europe, wheat, (Triticum vulgare) is cultivated chiefly in the zone between lat. 36° and 50°; farther north, rye (Secale cereale) is generally preferred. To the south of this zone, new combinations of heat, with humidity, and the addition of many other cultures, sensibly diminish

the importance of this precious cereal. The isochemial curve of 68° or 69°, which appears to be the extreme limit of the possible cultivation of wheat towards the equator, oscillates between lat. 20° and 25°. The cultivation of wheat is very productive in Chili and in the united state of Rio de la Plata. On the plateau of southern Peru, Meyer saw most luxurious crops of wheat at a height of 8500 feet, and at the foot of the volcano of Arequipo, at a height of 10,600 feet. Near the lake of Tibicaca, (12,795 feet high,) where a constant spring heat prevails, wheat and rye do not ripen, because the necessary summer heat is wanting; but Meyer saw oats ripen in the vicinity of the lake."*

1906. Barley. Its botanical position is the 3d class Triandria, 2d order Digynia, genus Hordeum, of the Linnæan system; and in the natural order of Graminea by Jussieu. Dr Lindley places barley, in his natural system, in class iv. Endogens; alliance 7, Glumales; order 29, Graminacea, and genus 11, Hordei, the same position as wheat. Professor Low divides the cultivated barleys into two distinctions, namely, the 2-rowed and the 6-rowed, and these comprehend the ordinary, the naked, and the sprat or battledoor forms.+ Mr Lawson describes 20 varieties of barley; while the Museum of the Highland and Agricultural Society contains specimens of 30 varieties. § The natural classification of barley by the ear is obviously of three kinds-4-rowed, 6-rowed, and 2-rowed. Fig. 180

§ Catalogue of the Museum, p. 60.

represents the 3 forms, where a is the 4-rowed, or bere or bigg; o is the 6-rowed; and b the 2-rowed; all which figures represent the ear in half its natural size. Of these the bere or bigg was cultivated until a recent period, when the 2-rowed has almost entirely supplanted it, and is now the most commonly cultivated variety, the 6-rowed being rather an object of curiosity than culture.

1907. In classifying barley by the grain, there are just two kinds, bere or bigg, and barley, Fig. 181. and, though both are awned, they are sufficiently marked to constitute distinct varieties. In the bere, fig. 181, the median line of the bosom is so traced as to give the grain a twisted form, by which one of its sides is larger than the other, and the lengthened point is from where the awn has been broken off. The figures represent the grain of the natural size.

SCOTCH BERE OR BIGG.

1911. A good crop of barley yields a return of from 48 to 60 bushels the imperial acre. Good barley weighs from 55 lbs. to 59 lbs. per bushel. A crop of 60 bushels per acre will yield of straw, in the vicinity of a town, 176 stones of 14 lbs. to the stone, or 1% ton, and the weight of the grain of that crop, at 56 lbs. It takes of bigg per bushel, will be 14 ton. 111 grains to weigh 1 drachm; of 6-rowed barley, 93; and of Chevalier barley, 75 grains.

1913. The use of malt in this country has fallen off materially during the last hundred years, when compared with the number of the people; but it would not be correct to attribute the circumstance wholly to the effect of taxation, although there can be no doubt that the consumption has been materially checked by the duty imposed. The introduction of tea and coffee into extensive use throughout the kingdom must necessarily have interfered with the consumption of beer; and the same effect must have followed the increased use of spirits, only a small proportion of which is distilled from malted grain.

1915. "The importation of malt from foreign countries is strictly prohibited; and as from some cause or other, not very well understood, barley brought from beyond seas cannot be profitably malted here, our landowners," observes Mr Porter, "enjoy the practical monopoly of the home market. The foreign-grown barley that is sometimes imported is used for grinding, and other purposes for which inferior qualities are adapted, and thereby admits of a more extensive use of the superior home-grown barley in the form of malt. When the corn trade was free, and the duty on malt was more reasonable than it has been of late years, the barley districts of England afforded an abundant supply of a quality adapted to the use of the maltster."*

1916. Pot and pearl barley are made from barley for culinary purposes; and both meal and

"That

1920. The grains of the fecula of the barley are very fine, not exceeding .00098 of an inch in size. Barley flour only contains 3 per cent of gluten, and is therefore much less nutritive than wheaten flour. The hordein, ascribed by Proust to act so important a part in the germination of barley, is asserted by Raspail to be nothing more, under the microscope, than bran. this is the case," he says, "is proved by dissection; for if we make a transverse slice of each of the grains of wheat and barley, we shall perceive that the pericarp of the wheat peels off entire like a circular band, while that of the barley can only be detached in very small fragments. Now, what takes place, under the edge of the scalpel," he alleges, "will also happen under the pressure of the millstones; consequently, the bran will be much more minutely divided in the farina of barley than in that of

wheat. In boulting flour, therefore, it will remain in the sieve; while, in the other, its almost microscopic fragments will pass through with the fecula and gluten, and will be almost inseparable, by mechanical means, from the farina." Hence, if pearl barley "be ground, we obtain from it a farina as white as that of wheat, and containing only a very minute portion of hordein, equivalent to the amount of those fragments of the pericarp which had been protected by their situation in the posterior groove of the grain."+

1921. "The meal so highly commended by the Greeks was prepared from barley. It was not until after the Romans had learnt to cultivate wheat, and to make bread, that they gave barley to the cattle. They made barleymeal into balls, which they put down the throats of their horses and asses, after the manner of fattening fowls, which was said to make them strong and lusty. Barley continued to be the food of the poor, who were not able to procure better provision; and in the Roman camp, as Vegetius has informed us, soldiers who had been guilty of any offence were fed with barley instead of bread corn."+

siderable change in the constitution of the grain. 1922. Malting. This process produces a conThe barley is steeped in cold water for at least 40 hours, according to law. Here it imbibes moisture, increases in bulk, and emits a quantity of carbonic acid gas, not exceeding 2 per cent. The moisture imbibed is 0.47, that is to say, every 100 lbs. of barley, when taken out of the steep, weighs 147 lbs. The increase of bulk is one-fifth, that is, 100 bushels of grain measures out 120 bushels. The steep water dissolves from to of the husk of the barley, and hence barley becomes paler by steeping. The steeped barley is then put on a floor in a heap 16 inches deep, to remain so for 26 hours. It is then turned with wooden shovels, and diminished in depth to a few inches by repeated turnings. In 96 hours the grain becomes 10° hotter than the air, and then sweats, when it is frequently turned, the temperature being preserved in the grain from 55° to 62°. The roots now begin to appear, the stem called acrospire, springs from the same end, and advances within the husk to the other end of the grain; but the process of malting is stopped by kiln-drying before the germ has made much progress. The kiln, at first 90°, is raised gradually to 140°. The malt is then cleaned, and the rootlets removed, as they are considered injurious, and are called comins. Malt is from 2 to 3 per cent greater in bulk than the barley, and it loses one fifth or 20 per cent in weight, of which 12 per cent is lost by drying; so the real loss is only 8 per cent, accounted for by the steep water carrying away 1 per cent, dissipated on the floor 3 per cent, roots cleaned away 3 per cent, and waste per cent. The roots take away the

glutinous portion of the grain, and the starch is converted into a sort of sugar.

1923. Beer.-Beer is a beverage of great antiquity. "The earliest writer who mentions beer," commences Dr Thomson. in his account of the process of malting, of which the foregoing paragraph is the substance, "is Herodotus, who was born in the first year of the 74th Olympiad, or 444 years before the commencement of the Christian era. He informs us that beer was the common drink of the Egyptians, and that it was manufactured from barley, because vines did not grow in their country. In the time of Tacitus, whose treatise on the Manners of the Germans was written about the end of the first century of the Christian era, beer was the common drink of the Germans. Pliny mentions beer as employed in Spain, under the names of calia and ceria, and in Gaul under the name of cervisia. Almost every species of corn has been used in the manufacture of beer. In Europe it is usually made from barley, in India from rice, in the interior of Africa, according to Park, from the seeds of the Holcus spicatus. But whatever grain is employed, the process is nearly the same, and it is usual in the first place to convert it into malt."*

1924. "Barley is cultivated farther north than any of the other grains: fields of it are seen in the northern extremity, in the Orkney Islands, and in Shetland (lat. 61° N.,) and even at the Faröe Islands (lat. 61° to 62° 15′ N.) Iceland (lat. 63° 30' to 66° N.) does not produce it, although an industrious population have made every exertion to acquire some species of cerealia. In western Lapland, the limit of barley is under lat. 70° near Cape North, the northern extremity of Europe. In Russia, on the shores of the White Sea, it is between the parallels of 67° and 68° on the western side, and about 66° on the eastern side, beyond Archangel. In central Siberia, between lat. 58° and 59°. Such is the sinuous curve which limits the cultivation of barley, and consequently that of all the cereals. A little farther north, all employment of vegetables ceases, at least as an important object of nourishment the people live on the product of their cattle, as in the high Alps, or by hunting and fishing, according to locality. But beyond the limits of barley there occurs a narrow and indeterminate zone, in which certain early potatoes are cultivated, and where the snow does not cover the ground for a sufficient length of time to prevent the raising of some lichens, some fruits, barks, or wild roots, fit for the nourishment of man. As the introduction of the potato is, in comparison to barley, recent in these regions, it almost every where forms the limit between the agricultural and the pastoral or nomad life. From the importance of the cultivation of barley in the north, it is evident that wherever the human species has attained the

first stage of civilisation, the attempt will have been made to advance it as far as possible towards the pole. If, then, it is limited by a sinuous curve, as already explained, it is because circumstances of a purely physical nature oppose to it an insurmountable barrier. A mean temperature of 46° 4′ during summer seems to be, for our continent, the only indispensable condition for the cultivation of barley; in the islands of the Atlantic Ocean, a summer temperature of three or four degrees higher appears to be necessary for its success. Iceland, indeed, where this grain cannot be cultivated, presents in its southern districts at Reikavik, a mean temperature of 37°.4' for the year-24° for the winter, and 49°.4' for the summer. It appears that here considerable rains are the means of preventing the cultivation of cerealia. Thus the limit of barley in the countries where its cultivation is of the most importance, varies between 46°.4' and 49° of mean temperature, during summer. In the continental regions 46°.4' is sufficient ; but in the islands the excessive humidity requires to be compensated by a little heat in summer. Barley is cultivated as an alimentary plant as far as the northern limit of rye and oats. Farther north it loses its importance, and is very little cultivated. Between the tropics this cereal does not succeed in the plains, because it suffers from heat more than any of the other cultivated grains."+

1925. Oats.-Oats are cultivated on a large extent of ground in Scotland-one-fifth of the arable ground; and it is believed that no country produces of them greater crops of finer quality. The plant belongs to the natural order of Gramineæ, of the Jussieun system, and it occupies the class Triandria, order Digynia, genus Arena, of the Linnæan system. In Lindley's natural system it occupies class iv. Endogens, alliance 7, Glumales, order 29, Graminacea, and genus 9, Arenece. Its ordinary botanical name is Arena satica, or cultivated oat. The term oat is of obscure origin. Paxton conjectures it to have been derived from the Celtic etan, to eat. There are a great number of varieties of this grain cultivated in this country. Mr Lawson describes 38; § and 54 are deposited in the Highland and Agricultural Society's Museum.!!

1926. The natural classification of the oat by the Fig. 183.

grain consists only of two forms-one plump and short and beardless, as in fig. 183, which represents grains of the potato-oat, in different positions, beardless, plump, smooth-skinned, and shining, having the base, from which the rootlets emerge, well marked, and the end from which the germ rises short, and bluntly pointed.

THE POTATO OAT.