[Explain its action as a divisor.

How does charcoal protect composts against injurious action of rains?

How does it keep them moist?]

2d. In its capacity as a _divisor_ for manures, charcoal should be considered as excellent in all cases, especially to use with strongly concentrated (or heating) animal manures. These, when applied in their natural state to the soil, are very apt to injure young roots by the violence of their action. When mixed with a divisor, such manures are _diluted_, made less active, and consequently less injurious. In composts, manures are liable, as has been before stated, to become burned by the resultant heat of decomposition; this is called _fire fanging_, and is prevented by the liberal use of divisors, because, by increasing the bulk, the heat being diffused through a larger ma.s.s, becomes less intense. The same principle is exhibited in the fact that it takes more fire to boil a cauldron of water than a tea-kettle full.

3d. Charcoal has much power to arrest the pa.s.sage of mineral matters in solution; so much so, that compost heaps, well supplied with muck, are less affected by rains than those not so supplied. All composts, however, should be kept under cover.

4th. Charcoal keeps the compost moist from the ease with which it absorbs water, and its ability to withstand drought.

[What source of carbon is within the reach of most farmers?

What do we mean by muck?

Of what does it consist?

How does it differ in quality?]

With these advantages before us, we must see the importance of an understanding of the modes for obtaining charcoal. Many farmers are so situated that they can obtain sufficient quant.i.ties of charcoal dust.

Others have not equal facilities. Nearly all, however, can obtain _muck_, and to this we will now turn our attention.

MUCK, AND THE LIME AND SALT MIXTURE.

[What is the first step in preparing muck for decomposition?

With what proportion of the lime and salt mixture should it be composted?

Why should this compost be made under cover?

What is this called after decomposition?

Why should we not use muck immediately after taking it from the swamp?]

By _muck_, we mean the vegetable deposits of swamps and rivers. It consists of decayed organic substances, mixed with more or less earth.

Its princ.i.p.al const.i.tuent is _carbon_, in different degrees of development, which has remained after the decomposition of vegetable matter. Muck varies largely in its quality, according to the amount of carbon which it contains, and the perfection of its decomposition. The best muck is usually found in comparatively dry locations, where the water which once caused the deposit has been removed. Muck which has been long in this condition, is usually better decomposed than that which is saturated with water. The muck from swamps, however, may soon be brought to the best condition. It should be thrown out, if possible, at least one year before it is required for use (a less time may suffice, except in very cold climates) and left, in small heaps or ridges, to the action of the weather, which will a.s.sist in pulverizing it, while, from having its water removed, its decomposition goes on more rapidly.

After the muck has remained in this condition a sufficient length of time, it may be removed to the barn-yard and composted with the lime and salt mixture (described on page 115) in the proportion of one cord of muck to four bushels of the mixture. This compost ought to be made under cover, lest the rain leach out the const.i.tuents of the mixture, and thus occasion loss; at the end of a month or more, the muck in the compost will have been reduced to a fine pulverulent ma.s.s, nearly equal to charcoal dust for application to animal excrement. When in this condition it is called _prepared_ muck, by which name it will be designated in the following pages.

Muck should not be used immediately after being taken from the swamp, as it is then almost always _sour_, and is liable to produce sorrel. Its _sourness_ is due to _acids_ which it contains, and these must be rectified by the application of an alkali, or by long exposure to the weather, before the muck is suitable for use.

LIME AND SALT MIXTURE.

[What proportions of lime and salt are required for the decomposing mixture?

Explain the process of making it.

Why should it be made under cover?]

The lime and salt mixture, used in the decomposition of muck, is made in the following manner:

RECIPE.--Take _three_ bushels of sh.e.l.l lime, _hot from the kiln_, or as fresh as possible, and slake it with water in which _one_ bushel of salt has been dissolved.

Care must be taken to use only so much water as is necessary to dissolve the salt, as it is difficult to induce the lime to absorb a larger quant.i.ty.

In dissolving the salt, it is well to hang it in a basket in the upper part of the water, as the salt water will immediately settle towards the bottom (being heavier), and allow the freshest water to be nearest to the salt. In this way, the salt may be all dissolved, and thus make the brine used to slake the lime. It may be necessary to apply the brine at intervals of a day or two, and to stir the ma.s.s often, as the amount of water is too great to be readily absorbed.

This mixture should be made under cover, as, if exposed, it would obtain moisture from rain or dew, which would prevent the use of all the brine. Another objection to its exposure to the weather is its great liability to be washed away by rains. It should be at least ten days old before being used, and would probably be improved by an age of three or four months, as the chemical changes it undergoes will require some time to be completed.

[Explain the character of this mixture as represented in the diagram. (Black board.)]

The character of this mixture may be best described by the following diagram:--

We have originally--

+----------------------------------+

Lime-+ Salt

consisting of

+---Chlorine } Chloride

and } of

+-Sodium. } Sodium.

--Carbonic acid

and

--Oxygen in the air.

+-Chloride of lime.-+

+-Carbonate of Soda.

[Y]

The lime unites with the chlorine of the salt and forms _chloride of lime_.

The sodium, after being freed from the chlorine, unites with the oxygen of the air and forms soda, which, combining with the carbonic acid of the atmosphere, forms carbonate of soda.

Chloride of lime and carbonate of soda are better agents in the decomposition of muck than pure salt and lime; and, as these compounds are the result of the mixture, much benefit ensues from the operation.

When _sh.e.l.l_ lime cannot be obtained, Thomaston, or any other very pure lime, will answer, though care must be taken that it do not contain much magnesia.

LIME.

[What effect has lime on muck?

On what does the energy of this effect depend?

Why should a compost of muck and lime be protected from rain?]

Muck may be decomposed by the aid of other materials. _Lime_ is very efficient, though not as much so as when combined with salt. The action of lime, when applied to the muck, depends very much on its condition.

Air-slaked lime (carbonate of lime), and hydrate of lime, slaked with water, have but a limited effect compared with lime freshly burned and applied in a caustic (or pure) form. When so used, however, the compost should not be exposed to rains, as this would have a tendency to make _mortar_ which would harden it.

POTASH.

[Is potash valuable for this use?

From what sources may potash be obtained?