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will again very materially affect the vegetation. Professor Johnston says, that when the temperature of the air in the shade is no higher than 60° or 70°, a dry soil may become so warm as to raise the thermometer to 90° or 100°. The temperature in wet soils rises more slowly, and never attains the same height as in dry by 10° or 15° Hence, wet soils are called cold, evaporation causing it. This to be corrected by draining. “Dry sands and clays, and blackish garden mould become warmed to nearly an equal degree under the same sun; brownish-red soils are heated somewhat more, and darkcoloured heat the most of all."
The farmer, hitherto, never seems to have thought much about the analysis of soils, but it is one deserving of great attention, and can only be done by those who are well skilled in this department of chemistry, and can pay great attention to it.
A geological map of England, on a tolerably large scale, pointing out the extent of country over which any particular formation extends—whether chalk, red sandstone, &c.; also the coal fields--districts where the iron and other ores are found-slate, tin, lead, copper-and this coloured for the purpose, with references at the side, is a most useful piece of school apparatus ;-it not only gives a teacher an opportunity of pointing out where those minerals are to be found how they affect the agriculture of a district—the character of its population and their employments-attracting an agricultural or a manufacturing class --but the children get a great deal of information by examining the map themselves. I have very often found a boy answering questions on this subject of which I had no notion that he had any idea, and have found that he had got at the knowledge himself, from the inspection of a geological map on the walls of the room.
There are many things of an ordinary STATISTICAL kind, connected with our social economy, our manufactures, &c., which might be made subjects of useful lessons to the boys in a school; such as the population of the different parts of the United Kingdom at periods when a census has been taken the decennial increase, the average annual increase, and this whether greater in the manufacturing or agricultural districts the average number to a house, in 1831, in Great Britain 5.62, in 1841,5 44, so that, at the latter period, there would seem to have been an increase of houses in a greater ratio than the increase of population.
The average consumption of each person in some of the common articles of life would also be interesting, as affording ideas of a definite kind as to the average consumption of a family in a village, a town, a county, &c.
This was for the United Kingdom :
, 1841 .. 1.7.55 Of tea in 1831 .. 1 3.93
1 1841 .. 1 5.96 Soap, in 1831, 6.23lbs. each, and in 1841, 9.2lbs. each, showing that the nation is progressing in the use of soap in a greater ratio than in an increase of population, and that, if there is not an increased consumption of it in the arts, we are progressing in cleanliness.
Then, again, the consumption of coal as fuel, and the extent of our coal fields, how this enables us to turn large tracts of land to arable purposes, which, in this climate, must otherwise have grown wood ;-coal, for smelting purposes—for making gas to light our towns—this mode of lighting introduced at no great distant period, and better for the purpose than oil. · In England the coal field is about oth of the whole surface, in Belgium both, in France zioth. · Different kinds of coal differ in their heating powers.
Table showing the relative heating powers of certain combustible materials.
1.275 to 1.524
Economy of a Coal Field.—JOHNSTONE. The great improvement of late years in the habits of the upper and middle classes in this country, more particularly as to drunkenness—but not a corresponding improvement in the lower and working classes in this respect--this much to be regretted.
:: On manufacturing subjects. The number employed in each particular class of manufacture—the potteries —cotton, silk manufactures, &c.--cutlery, and working in metals, &c.where all these are carried on the increased value given to the raw material when worked up-this partly in proportion to the time and skill required.
There is on this subject some very instructive information, in a tabular form, in Babbage on the Economy of Machinery,' but the calculations are made for the year 1825, and therefore would not exactly apply at present.
The following are a few of them :
3.57 Barrels, musket
9.10 Blades, razor, cast steel » .
53.57 Blades, of table knives ..
35070 Door-latches and bolts, from . . . i 4.85 to 8.50 Files, common, became
2.55 Saws, for wood ,
14.28 Needles of various sizes, from . . . 1733 to 76.85
&c. &c. The above are given simply for the purpose of suggesting inquiry as to the value of labour compared with that of the material in manufactured products ;-other instances of a domestic kind would occur-such as the value of the raw material wool, of different qualities, compared with the price of a pair of stockings—a yard of flannel-of a coat of the kind ordinarily worn-of a hat, &c.
The increased value given to the skins of animals, when manufactured into shoes, gloves, harness, saddlery, or any other thing made of leather, &c.
Increase of value in flax when manufactured into linen, tablecloths, made into sheets, &c.,-pointing out the advan
tages to a country in being able to manufacture its raw products, whether of a mineral or a vegetable kind, over one which is obliged to export them in a raw state for the purpose of being worked up :- also to what causes it is owing that particular manufactures are located in particular districts - as that of cotton in Lancashire-woollen at Leeds - cutlery at Sheffield, &c.
Too much attention cannot be given to all these things of an industrial character, from which they can form a definite idea of the comparative money value which society pays for the various branches of industry, of skilled and unskilled labour, &c.
Of the extent to which internal communication and rapid modes of conveyance may increase the power and affect the productive industry of a country, the following passage taken from Babbage may give the reader some idea :
“On the Manchester railroad, for example, above half a million of persons travel annually; and supposing each person to save only one hour in the time of transit between Manchester and Liverpool, a saving of five hundred thousand hours, or of fifty thousand working days, of ten hours each, is effected. Now this is equivalent to an addition to the actual power of one hundred and sixty-seven men, without increasing the quantity of food consumed ; and it should also be remarked that the time of the class of men thus supplied is far more valuable than that of mere labourers.”
The above was written when the Manchester railroad was the only one established; the present state of things adds greatly to the interest of the observation.
A teacher ought to have a general knowledge of the ordinary things of life, so as to give a character of usefulness to his teaching, which will interest those who are taught, and also interest the parents who send them.
Short CONVERSATIONAL LECTURES, about fifteen or twenty. minutes long, will be found a very effective means of instruction. Subjects like the following would naturally suggest themselves :
Truth and falsehood-industry and idleness -sobriety and drunkenness-honesty and the reverse, &c.
In natural history; habits of birds -of animals, their instincts, &c.; or on subjects connected with the occupations of the district-agricultural employments-mining, manufacturing, &c.; on any particular application of substances with which they are acquainted, &c. And when a master is qualified, he might take such as the following:
The atmosphere-as a vehicle of heat and moisture-as a vehicle of sound: rain and clouds, &c., mist and fogs, &c., dew, &c.
To give an idea what is meant by conversational lessons, the following may be taken as illustrations :
A loaf of bread. The teacher would go on to explain that, the different substances of which it is composed are the flour of wheat, water, barm, salt; that these again are not simple, but each made up of many elementary substances into which they can be separated. : Flour contains gluten, starch, &c., which form the nutritive part of it as food.
Water can be decomposed into its elements, oxygen and hydrogen-two gases, which can be again reunited to form water.
Salt, of a gas, not colourless like the other gases, but yellow, which cannot be breathed, and a metal, sodium.
Barm, a froth which rises to the top of beer during fermentation. That if the smallest crumb of bread be taken, so small as to be only just visible, it will contain something of all these different elements ;--that if they divide this again into a thousand pieces, so as not to be visible even to the naked eye, each of these would contain something of all the different elements of the loaf. • Again, when the loaf is cut we see a number of cells of various sizes - how came these there? The barm causes a vinous fermentation to take place in the dough, by which an air, heavier than common air, and called carbonic-acid gas, is formed; this, as the dough warms, expands, tries to escape, but the dough, by its tenacity, retains it, and in this way these ·cells are formed.
Then, again, the number of people it has given employment to before it became bread: from the ploughboy up to the farmer - from sowing up to threshing .- from the farmer