Light in the Depths.

91

latter organisms being on the immediate surface-layer of the deeper oceanic deposits, and not in the substance of the superincumbent waters. At the same time it substantiates the truth of the star-fishes having been captured on their natural feeding ground.

'I also detected, in a sounding made at 1913 fathoms, a number of small tubes, varying in length from one-sixteenth to a quarter of an inch, and about a line in diameter, which, on being viewed under the microscope, turned out to be almost entirely built up of young Globigerine shells, cemented side by side, just as we find to be the case in the tubular cells of some of the cephalobranchiate Annelids, where sandy or shelly particles are employed in their formation. There can hardly be a doubt, therefore, that some minute creature, probably an Annelid, lives down at this enormous depth, and feeds on the soft parts of the Foraminifera, whilst he houses himself with their calcareous shells. As yet I have been unable to determine the nature of these creatures, but hope to be enabled to succeed on a more lengthened survey of the material in which they occur.

'Lastly, I would mention having met with the minute bodies termed "Coccoliths" by Professor Huxley. They occur in vast numbers, associated with larger cell-like bodies, on the surface of which Coccoliths are arranged at regular intervals, so as to lead to the inference that the latter are in reality given off from the former in some way. The larger cell-bodies, and the Coccoliths on them, are imbedded in a gelatinous envelope. The presence of these organisms in largest quantity in those deposits in which the Globigerinæ occur alive in the greatest profusion and utmost state of purity, would also seem indicative of their being a larval condition of the latter.'

As the supposition that the pressure of so great a body of water would preclude the possibility of animal functions being carried on at the bottom of the ocean, is thus found to be a mistake; so it is by no means improbable, that our received theories of absolute darkness at that depth may be equally mythical. Edward Forbes formed an ingenious hypothesis touching the distribution of marine animals in zones of depth, from facts which seemed to prove that positive colour diminished in the shells of the Mollusca, in the ratio of their habitual distance from the surface, all colour ceasing at from fifty to one hundred fathoms. It was hence assumed that light was entirely lost by absorption, in passing through such a volume of sea-water. Subsequent researches, however, by Sars, and other Norwegian naturalists, proved the existence of certain Anemones

and corals at a depth of two hundred fathoms; and these are by no means white, as this hypothesis required, but adorned with the most vivid hues. Light, then, must exist, and have a strong colorific power at that depth. Dr. Wallich has not alluded to the colours of his Ophiocome; but as he compares it to 0. granulata, we may fairly assume that there was no great disparity in hue. Now this species is of vivid colours :-black, brown, orange, roseate, are the tints of the disk; and that of the rays, dusky white, or bluish. Can the colour-producing rays of the sun, then, penetrate through a stratum of water a mile and a half thick? No;' say the philosophers, 'absurd!' 'Yes;' says the Ophiocoma, 'ecce signum !'

ART. IV.-1. Tillage a Substitute for Manure: Illustrated by the Principles of Modern Agricultural Science and the Precepts and Practice of Jethro Tull; including an Epitome of Tull's operative Directions in successive unmanured Corn Culture, and the Particulars of Lois Weedon Husbandry, and other Instances of Tull's Method of Farming. By ALEXANDER BURNETT, M.A., Land Agent, Member of the Royal Agricultural Society, and the Central Farmers' Club, London. London: Whittaker and Co.; Chester: Hugh Roberts. 1859. 2. Lois Weedon Husbandry. Second Edition. By this mode of Husbandry, compared with the ordinary modes, the moiety of an acre yields more than the whole.'-Hesiod, free translation. By the Author of A Word in Season to the Farmer.' [By the REV. S. SMITH.] London: J. Ridgway. 1859. 3. A Word in Season: or, How to grow Wheat with Profit. By the Author of Lois Weedon Husbandry.' Seventeenth

Edition. With large Additions about Tull and Liebig. [By the REV. S. SMITH.] London: J. Ridgway. 1859. 4. The Horse-hoeing Husbandry: or, A Treatise on the Principles of Tillage and Vegetation, wherein is taught a Method of introducing a Sort of Vineyard Culture into the Cornfields, in order to increase their Product, and diminish the common Expense. By JETHRO TULL, of Shalborne, in the County of Berks. 1733. Republished by W. Cobbett in 1829. (Out of print. Copy in British Museum Library.)

'WHO was Jethro Tull? and what was his system of husbandry? We fancy we hear a farmer of the old school say: 'O, he was one of your book-farmers, who could grow corn upon a barn-floor; he was cousin-german to the man that made deal

boards out of sawdust, and hunted after the philosopher's stone. He lived nobody knows how many years ago, and died, they say, as poor as a rat, after spending a fortune in following a Jack-o'lantern,' &c. Now let us hear what Jethro Tull says of himself, or, rather, of the principle on which he acted in life.

'No canon having limited what we shall think in agriculture, nor condemned any of its tenets for heresy, every man is therein a free thinker, and must think according to the dictates of his own reason, whether he will or not. And such freedom is given, now-a-days, in speculations in natural philosophy, that it is common to see people, even in print, maintain that there are antipodes, and that the earth moves round the sun, and that he doth not set in the sea, without being censured for these, and many other formerly heterodox opinions; and every one may now, upon solid argument contradict Aristotle himself publicly any where, except in the Schools.'

We have put this passage in italics, but it deserves to be printed in letters of gold: because, in the first place, it was written at a period when science and agriculture were both in their infancy; and secondly, because it equally applies, and equally needs to be repeated, in the present day, when both are in their manhood, and at the zenith of their glory and power.

Jethro Tull was, in fact, born a century and a half before his proper time; and the consequence has been, that the principles on which he wrote and acted have had a long intermission of slumber, with the exception of a few snatches of revivification, until the present day, when the light of knowledge has broken in upon the last of our uncivilized tribes, undignified with the title of 'strawyard savages.' In Tull's day, science had made little advancement, and that little had been chiefly confined to a small class of men. Jethro Tull's strong intellect had broken through the trammels with which the agricultural mind of that day was fettered; and having, either by accident or by inductive investigation, discovered what he considered to be the true principles of vegetation and fertility, he at once, in the face of clamour, abuse, and every kind of opprobrium, set to work to carry them out in his practice of farming. In this he persevered until his death in 1741; having, up to that period, grown thirteen consecutive crops of wheat on the same field without manure, without diminution of produce, and without deterioration of soil or quality of grain. His experiments, too, may be said to have been conducted upon a rather large scale; for they embraced 120 acres of land.

The principle on which the Tullian system rests is this, that the atmosphere alone contains all the elements of fertility necessary for the support and maturation of vegetables; and that nothing is

wanted to insure and promote their beneficial absorption by the soil, and assimilation by the plants, but rest, with incessant tillage and comminution. Tull therefore adopted a plan of his own, by which he secured both these objects without losing a crop. It was as follows:-A field having been well tilled during a 'bare fallow,' and thrown into ridges of six feet, or of four feet eight inches each, according to his ultimate practice, he drilled along the centre of the ridge from one to four equidistant rows of wheat, according as experience led him, from year to year, to vary the number; and thus each set of rows was flanked, right and left, by an unseeded space, bounded exteriorly by the 'bared balk.'*

We thus find that half the land was left unsown; and have now to explain the treatment these spaces received during the growth of the crops by their sides.

First, by virtue of spring and summer horse-hoe workings in these, conjointly with hand-hoeing in the rows, the extermination of every kind of foul vegetation was attained. Secondly, the soil composing them became, by means of that continuous tillage, a highly fertilized source, from which, in addition to the sustenance yielded by the mould of the rows, the growing plants were able to draw more and more nutrition, the more and more their increasing bulk demanded it. And, thirdly, these uncropped spaces ultimately became, by that operation of the plough termed feering,† the seed-beds (accumulated in the bared balks) of the next ensuing crop.'-Tillage and Manure, p. 105.

It will be observed that Tull used the plough in his system of tillage. We therefore next refer to the practice of the Rev. Samuel Smith of Lois Weedon, who has adopted the alternate cropping and fallowing of Tull, but substituting the spade and fork for the plough. Another difference, too, in their practice must be noticed. Tull carefully avoided raising any part of the subsoil to the surface, confining his tillage to the staple soil, which probably was not more than five inches. Smith, on the contrary, using the spade or fork, turns up a portion of the fresh subsoil every year; so that his land, after a few years, becomes thoroughly subsoiled. The land being thus prepared, his after operation is as follows. Three rows of wheat are drilled or dibbled at from ten to twelve inches ‡ between them. An equal space of ground is then left vacant or unsown, to be treated as

* Tillage and Manure, p. 105.

Feering. This should have been rendered veering. Tull explains in a note, that it is a technical term of the ploughmen, signifying turning two furrows towards each other, as they must do to begin a ridge. It is taken from the seamen, and means, to turn.'

Tull, after many years' experience, adopted ten inches between the rows as the most profitable, and planted, at times, only two rows on a ridge.

we shall presently describe. Then another three rows of wheat are planted, and another space left vacant; and so on until the whole field is gone over, and half of it planted; no manure whatever having been used or applied in any one year throughout the thirteen years that Mr. Smith has practised the system. During the growth of the crop the void intervals are, from time to time, kept open by the spade and fork, whilst the rows of corn are well cleared and stirred by the horse hoe, so as both to destroy all weeds, and open the soil for the influences of the atmosphere. In this respect the practice of Tull and his imitators is similar, both considering it necessary to keep the soil open. Towards harvest, when the wheat has attained its full stature, a furrow is turned by the plough, so as to fall against the outside rows on each side; this is done to strengthen the straw, and prevent its being lodged by the wind or rain. By the above treatment, Tull, and those who copied him, have found that by successive cropping with wheat the soil has received no deterioration. On the contrary, the produce has increased by the superior condition and cleanliness of the land, which, on this system, receives a fallow every other year.

We have said that Tull was born a century and a half before his time. This was true in more senses than one; for, not only was agriculture at a very low ebb, but science itself could scarcely be said to be born. The elements of fertility which, as Tull suspected, and ultimately became convinced, were supplied by the atmosphere, had never been identified, because the then mysterious fluid itself had not been analysed. The gases of which it is composed were not discovered till some years after his death, when Priestley unravelled the mystery, and determined by his ingenious investigations the component parts of that aëriform combination of vapours, by which all life, animal and vegetable, is sustained. In this respect, Tull laboured under a manifest disadvantage, being ignorant of the precise nature of those substances which, as bis inductive observation had enabled him to perceive, could have no other origin than the atmosphere. In combating, therefore, his opponents, he could only point to the results of his practice, without giving a definite explanation of the elements by which they were produced.

It will be seen by the title of Mr. Burnett's work, that its object is to place before the public the theoretic principles of the Tullian system, illustrated by the practice of several cultivators, who have from time to time wholly or in part adopted it. The two works of Mr. Smith are details of actual practice on the system, and contain an ample and satisfactory account of the results. Mr. Burnett thus explains his object in the preface: