springs, should it be too great. To a circular block of wood, having four holes and fixed on the wheel, one end of the feeding arm is screwed, and is fixed to the cross bar by a pin, moveable at pleasure to five different holes, by which arrangement twenty different changes of length of chaff may be obtained. Two spiked rollers in the box are turned from the outside by ratchet wheels, so that the straw is at rest during the time the knife is cutting upon it. A weight is suspended by a lever under the box, which will assist in forcing the straw forward, and counterbalance the ratchet wheel of the upper roller. Equal pressure is given to the straw by a chain passing from near the fulcrum of the lever to a roller with two small bars of iron, which are attached also to the projecting axle of the upper feeding roller. Passmore's machine, it will be perceived, was very similar, but its mechanical combinations are advantageously simplified. In 1800 and 1801, W. Lester of Paddington patented a straw-cutter, which, with some alterations, is much used at the present day, and is known as the "Lester engine." It is a very simple machine, having but one knife, placed on a fly-wheel; the fly-wheel turns on a cranked spindle, which communicates motion to a ratchet wheel

fixed at the end of one of the feeding rollers by means of a small hook or catch, which is capable of being so adjusted as to lift one two, three, or four teeth at each revolution, and by this is regulated the length of the straw projected in front of the face plate, and which is severed by the knife. On the roller was fixed a revolving cloth or endless web, which passed over another roller at the hinder end of the box; a heavy block was used to compress the straw. In the more modern engines the rolling cloth is entirely dispensed with, as the purpose for which it was intended is effected by the introduction of an upper feeding roller, to which motion is communicated by a pair of cog-wheels, one of which is attached to the lower feeding roller before described; the heavy block is substituted by a pressing piece, which receives its motion from the cranked spindle, alternately presses down the straw previous to the cut, and rises afterwards to allow the straw free passage. A cut of the improved machine is here given; it is made of different sizes, and the larger are frequently used with horse-power.

This is the best modern chaff-engine; it will adjust and vary the work to the following lengths of cut:-inch, inch, and inch.

improvements on this machine, one by Lord Ducie in connection with Messrs Clyburn and Budding, two engineers residing at Uley.

The only remaining machine we have to

principal, but a size smaller, which

at inch will cut from 10 to 12

A still smaller engine can also be had, cutting inch lengths only, suited to gentlemen's stables and small establishments,

made entirely of metal, and adapted for hot climates. This will cut from 15 to 20 bushels of fodder per hour.

Passing by several, which in the course of the next fifteen years were introduced, but which, however ingenious, were too complicated and cumbrous for general use, in 1818 we find a simple invention was patented by Thomas Heppenstall, of Doncaster. It consisted in the application of a worm to turn two wheels, which in their revolution meet each other. These wheels are attached to two feeding rollers, which convey the straw forwards to the knives. Two of these knives are placed on a fly-wheel, which is fixed upon the same spindle as the worm. This is the simplest form of chaff-engine, and with a slight alteration, substituting wheels with the cogs on the face instead of on the outer edge, is the common form for the small engines now in use.

Two patents have also, within the last year or two, been taken out for considerable

one for which a patent was obtained a few months ago by Mr. Charles May, engineer of Ipswich, a partner in the house of Ransome. We saw this among the machines exhibited at the Royal Agricultural So ciety's meeting at Cambridge, where it ap peared to perform its work admirably. 1 is intended to be used by horse-power, and is so contrived that cog-wheels of different diameters, may be placed on the spindle to which motion is first communicated; working in different moveable wheels upon another spindle, will regulate the speed of the feeding rollers, so as to vary the length of the chaff to be cut, from three-eighths of an inch to three inches. Its capabilities are estimated to cut 8 cwt. of straw per hour in half inch lengths.

these

A chaff-cutter is indispensable on a large farm establishment. This implement, has been shown, is either constructed with a good deal of expensive machinery, or of very simple mechanism; it may be made up at the cost of only 17. or 11. 58.

The following is a list of the patents which have been taken out for chaff-cutting machines, or improvements thereon, during the last half century:

January 8. 1794. Rev. J. Cooke, Holborn, machine for cutting chaff.

Carbonate of lime is found in almost all vegetables; it is an essential food of plants. The cultivator will see, by the results of the experiments which I shall give under the head LIME, that the quantity of carbonate of lime contained in the cultivated grasses is very considerable, and still more so in trees; and that, as might be expected, the proportion increases with the quantity of this substance found in the soil. To the planter, this fact offers an unanswerable reason in favour of the addition of chalk, marl, or limestone, to all poor soils intended for plantations, in the manner long successfully practised on the black heathy sands of Norfolk by Mr. Withers of Holt, and which he has shown to be equally advantageous to trees, whether planted for ornamental or profitable purposes.

pre

There is no fact more necessary to be understood by the agriculturist, than that no land can be productive which does not contain a fair proportion of carbonate of lime. It is, perhaps, even in excess much less judicial to any cultivated soil, than either silica or alumina. But, on the other hand, no soil can be productive if it contains more than nineteen parts in twenty of chalk. The earth of the fine sandy hop gardens near Tonbridge in Kent contain about five per cent. of chalk. The good turnip soils near Holkham in Norfolk are seven eighths sand, and the remaining eighth is composed of

Carbonate of lime or chalk
Silica (flint)
Alumina (clay)

Oxide of iron

Vegetable and saline matter Water

Parts.

63

15

11

3

The soil at Sheffield Place in Sussex, which is so admirably adapted for the growth of the oak, contains three per cent. of chalk. The fine wheat soils of West Drayton in Middlesex contain more than ten per cent. That of Bagshot Heath contains less than one per cent. The richest soils on the banks of the Parret in Somersetshire contain more than seventy per cent. Those of the valley of Evesham, about six cent. A specimen of a good soil from Tiviotdale, examined by Davy, was composed of five sixths sand, and the remainder of the following substances (Lectures, 202.) :

per

Vegetable, animal, and saline matter

Parts.

41

42

4

5

8

A soil yielding excellent pasture, from

Many soils also contain a small proportion of carbonate of magnesia; but it very rarely amounts to a sufficient quantity to be worth estimating in the mode of analysis I shall presently give.

It is difficult to say in what form the carbonate of lime enters the system of plants, as it is an insoluble compound: unless we can suppose that it attracts an excess of carbonic acid from the air, becoming a bi-carbonate, in which state it is soluble in water. But whatever may be the cause of its being taken up by plants, its influence on soils is undoubted.

The mode of applying chalk as a manure. In the county of Essex, where chalking is practised to a very large extent, the chalk is brought in sailing barges from the Kentish shore of the Thames, at an expense of about two shillings per ton, and afterwards carted for some miles into the country. It is applied in quantities which vary from ten to thirty tons per acre, according to the description of the soil; the poor light soils requiring a larger addition of chalk than the richer lands. It is usually applied without any preparation; the larger lumps of chalk are not even broken, and the chalk being once ploughed in, the action of the frost, the plough, and the harrow, in time sufficiently pulverises it. It is often mixed in smaller proportions with common farm-yard manure, ditch scrapings, pond mud, &c. and suffered to remain some time before it is carried into the field. equally excellent plan is followed by some of the best Essex farmers, who spread quantities of chalk over head lands, banks, &c. which require lowering, and then fallow these portions of land, ploughing them often, and letting the chalked earth remain as long as possible incorporating before earth on to the field; by this means the they carry and spread the mixed chalk and effects of a few loads of chalk are diffused over a field. It is a plan admirably adapted for those situations where chalk is very expensive.

An

The good effects of chalk are more permanent than immediate; for, although a good dressing with chalk will remain in the soil for from ten to twenty years, yet, on some soils, one or even two years will elapse