We have some practical remarks for publication next month on the Orchard House in America, by our practical friend " Fox Meadow".

Letters on Modern Agriculture, by Professor Liebio, edited by John Blyth, M. D., is the title of the new work issued in London. It has not reached our table, and we must be content to take at second-hand a few extracts from English journals:

"Nothing," says the Gardener's Chronicle, "can be more just than the following comparison of the plough and the spade, and we trust that cultivators will appreciate it; for it involves some of the greatest of truths, an entire conviction of the importance of which .is ail that is wanted to terminate the career of an antiquated implement whose merit consists in its ability to perform much bad work in little time.

"If the food of plants in the soil cannot move towards the roots, it is evident that the roots must spread about to look for food.

"A piece of bone weighing about 30,000 milligrammes (one ounce), in a cubic foot of earth, produces no marked effect on its fertility. But if these 30,000 milligrammes of phosphate of lime be uniformly distributed throughout the earth, it will suffice for the nourishment of 120 wheat plants. Ten thousand milligrammes of food, having a surface extent of 100 square millimetres, are within the same given time not more effective than ten milligrammes having the same surface extent. Of two fields with the same amount of food, one may be very fertile and the other equally unfruitful, if the food is more uniformly distributed throughout the former than the latter.

"The common plough breaks and turns up the soil without mixing it; it only displaces, to a certain extent, the spots on which plants are already grown. But the spade breaks, turns and mixes it thoroughly.

"As the smallest portions of food cannot of themselves leave the spot in which they are held firmly fixed by the soil, we can understand what immense influence must be exerted on its fertility by its careful mechanical division and thorough intermixture. This is the greatest of all the difficulties which the agriculturist has to overcome.

"Professor Liebig strongly advocates the use of green manures, a system pursued extensively on the continent of Europe.

"The keeping of cattle is necessary for the production of manure; but the production of manure is by no means necessary for the fertilization of corn fields. In the system of the rotation of crops, all that is required is that green crops should be grown, and that their constituent parts be incorporated with the arable surface soil of the field; and it is quite immaterial for the cereals whether the green crops be previously eaten by the cattle and converted into manure or not. If lupines, vetches, clover, turnips, etc, are cut up and ploughed in, in the green state, their action is far more powerful".

The following truth, so little appreciated, is happily put: " The technical part of an industrial pursuit can be learned; principles alone can be taught To learn the trade of husbandry, the agriculturist must serve an apprenticeship to it; to inform his mind in the principles of the science, he must frequent a school specially devoted to this object. It is impossible to combine the two; the only practicable way is to take them up successively. I formerly conducted at Giessen a school for practical chemistry, analysis, and other branches connected therewith, and thirty years' experience has taught me that nothing is to be gained by the combination of theoretical with practical instruction. A student of chemistry, who attends the lecture-hall and the laboratory concurrently, positively defeats thereby the object of his stay at the school, and misses the aim of his studies. It is only after having gone through a complete course of theoretical instruction in the lecture-hall that the student can with advantage enter upon the practical part of chemistry; he must bring with him into the laboratory a thorough knowledge of the principles of the science, or he cannot possibly understand the practical operations.

If he is ignorant of these principles, he has no business in the laboratory.

In all industrial pursuits connected with the natural sciences, in fact, in all pursuits not simply dependent on manual dexterity, the development of the intellectual faculties, by what may be termed 'school-learning,' constitutes the basis and chief condition of progress and of every improvement. A young man, with a mind well stored with solid scientific acquirements, will, without difficulty or effort, master the technical part of an industrial pursuit; whereas, in general, an individual who may be thoroughly master of the technical part is altogether incapable of seizing upon any new fact that has not previously presented itself to him, or of comprehending a scientific principle and its application.

"I have often found that students coming from good colleges will speedily leave the pupils of industrial and polytechnic schools far behind them even in the natural sciences, though the latter, when compared with the former, were at first giants in knowledge".

The New Grass, Spergula pilosa, seems to be making its way to public favor abroad. Mr. D. Beaton, one of the principal writers of the Cottage Gardener, says in that journal: -

"I am not long in deciding on a thing of this kind, and am often put down as being too sanguine in these matters; but it is seldom indeed that things go different, or very different, from what I say. I say, then, of this lawn plant, that it is destined to make a revolution in gardening; that it is a discovery next to that of gas, steam, and electricity, for gardening; that every lawn in England, Ireland and Scotland may be made with it as smooth, and soft, and comfortable to walk on as any carpet in Her Majesty's drawing-rooms; and that it never wants a scythe or a mowing machine. The best lawns and the best carpets have worn out, hitherto, by time and usage, and so will this grass; but, of all the things on the face of the earth, it is the easiest thing to 'make up,' and to look as well as it did before. It will require the highest style of gardening, and it will teach this nation how gardening should be done. One of our best exhibitor-gardeners has pledged his credit, in my hands, on the point that he would willingly undertake, in one season, to cover every inch of ground which is under the scythe at the Crystal Palace with this new grass.

"A large piece of lawn, nine yards by eight yards, is already formed of it at Forest Hill; and two larger pieces of lawn, each thirty yards by sixteen yards, are now in the course of being covered with it; and ultimately every inch of the lawn all over the garden is to be covered with it, and with nothing else.

"No one can conceive the beauty of it without seeing it. The nap on the finest velvet is not more soft or more uniform; and there is a gloss all over the surface like that on the back of a mole. The garden where this has been proved is as steep as on the side of the Malvern Hills, and is of the strongest red clay; but the Spergula takes hold of the gravel walks just as readily as of this clay. It is like a mulching over the clay, which never allows the clay to crack, be the Bummer ever so hot.

"The history of it is this. The proprietor, A. Mongredien, Esq., is a practical botanist; and to indulge in his favorite pursuit he has formed the most unique rock garden in the three kingdoms, at the foot of the slope, facing the north, for the growth of the fairest and scarcest cryptogamic plants in the British flora, from the tiniest ferns, through lycopodiuin, sphagnum, phascum, gymnostomum, Hymenostomum, trichostomum, dicranum, tortula, bryum, polystichum, hypnum, jungermannia, marchantia, and their extensive allies; also for British orchids, and the minutest and rarest alpine plants. Among the last, Spergula pilosa, as it is called, made its appearance; and increased so fast, and showed such delicate proportions, and such an inclina-tion not to be kept within the limits of its duo portion of the rock-work, that it seemed selfish to destroy so much of it without allowing kindred spirits to partake of the same pleasure and amusement. Patches of it were set in better soil, and better returns were made by it; till at last, from patchwork to a whole quilt, and from that to a full-stretched carpet, which you have just heard of, were made with ease and pleasure. * * But some of the great firms in the seed trade about London would not, or could not, believe in such marvels; they must see for themselves.

They did see, and were convinced that a tithe of the " properties" of this plant was not given. * * Mr. Summers has undertaken the responsibility of supplying the three kingdoms with plants sufficient to set the plant on foot, through the Messrs. Henderson, of the Wellington Road Nursery; that he has rented a greenhouse and so much ground for that purpose, and engaged a managing foreman to propagate the plant by the thousand and tens of thousands; that the concern will be' called the Spergula Nursery; that he will, or could, undertake to cover the whole of the Crystal Palace grounds with this plant in one season; but for the present, and to such a period', applications for it must be made through the Wellington Road Nursery." This all seems like success, and we hope it may so prove.