ART. III. Notes on the former and present State of Horticulture in Ireland. By Mr. JOHN ROBERTSON, F.H.S.

Sir,

I SEND you the following memoranda, partly taken from an article entitled "Dubliniana" in the Pilot newspaper of November 9., and partly my own remarks on the memoranda, and on the former and present state of horticulture in this country.

"The Use of Sea-kale as an esculent Vegetable is supposed to be of recent date, and was first introduced, as has been said, by the present Bishop of Carlisle, who cultivated it in his garden for asparagus; but, so long ago as the year 1764, this plant was cultivated in the gardens of Dublin, and the seeds sold in the shops. When the seeds were sown, they were covered over with gravel; the shoots were used in spring, as they are now, and preferred to any other species of kale. It was the practice, however, to boil them in two different waters, to extract the salt, with which the plant was supposed to be impregnated, from its marine origin. The valuable property, also, which distinguishes it from other kales, that the root is perennial, and will bear cutting for forty years, was well known. (Tutty, vol. i. p. 4.) The sea-kale grows at present, in great abundance, on every part of the sandy shores around the bay of Dublin, and is cultivated in every garden in and near the city.

"Pine-apples were first brought to Dublin by a man of the name of Buller, who, in the reign of Queen Anne, settled in the vicinity of Dublin, and held an extensive nursery in New Street, where traces remain of it to this day.

"In the reign of George I., the Hugonots established a Florists' Club, for the purpose of promoting the cultivation of flowers, and held their meetings at the Rose tavern, Drumcondra. They were continued until the reign of George II.; but the science of gardening was, from that time, entirely neglected, until a number of the principal gardeners, in the vicinity of Dublin, assembled at the Rose tavern, Drumcondra, on Sept. 30. 1816, and formed themselves into a Horticultural Society."

The writer must have been misinformed when he says that pine-apples were introduced to Dublin in the reign of Queen Anne. They were only cultivated in England late in that reign, for the first time. If introduced first to Dublin by Buller, it should have been the reign of George II.: there were but two nurserymen of that name there in succession. I recollect having seen the younger Buller myself, at his seedshop in Pill Lane, about the year 1776. The elder was in

business about 1756, as my father purchased from him, then, a stock of pine plants, perfectly clean and free from insects: and it may be worth remarking, as rather a rare instance of any such pedigree, and so remote, that from that stock has descended to me the one which I am at present in possession of equally free from insects, and that solely by guarding against their intermixture with any other: perhaps the only effectual way of preserving pine plants clean, notwithstanding all the nostrums that have been recommended.

However horticulture may have been neglected about Dublin at the period mentioned by the writer, it is not to be taken for granted that it was so in other parts of Ireland. Kilkenny, at least, forms an exception, as it never was so flourishing there as then.

Drawing a radius of ten or twelve miles round that city, you would, to my knowledge, for twenty or thirty years from 1785, reckon within the circle a dozen gardens or more, each of which contained pine-stoves, from 50 to 100 ft. in length; and other forcing-houses corresponding *, well stocked and managed by able gardeners from Kew, Hampton Court, and other places of note round London. Now we cannot count half the number: the Union has rendered some of our great landed proprietors absentees; and the fall of lands and prices has disabled others, and has swept off a number of landholders, who were rapidly improving the face of the country by building, farming, planting, and gardening: so that horticulture in Ireland, as far as my observation extends, was never at so low an ebb as at the present moment. I am, Sir, &c.

Kilkenny, Nov. 1829.

JOHN ROBERTSON.

ART. IV.

Outlines of Horticultural Chemistry: - Diseases of Plants. By G. W. JOHNSON, Esq., Great Totham, Essex.

(Continued from Vol. V. p. 409.)

THE following sketch (fig. 7.) represents the apparatus I have found the best for ascertaining the retentive power of soils. a represents a small lamp; b, a tripod for supporting a small tin

As an instance, fifty years ago the present Dowager Countess of Ormond had her table regularly served, through the winter with cucumbers raised in her pine-stoves on treillages against the back wall; though, only the other day, Mr. Aiton, the king's gardener at Kew, had a medal presented to him by the Horticultural Society, for the introduction of the practice about London.

vessel c, which has a small hole and plug at g, for the purpose of filling it with water; and a small pipe d, for the escape of the steam when the water is brought to a boiling temperature; h is a small pair of grain

scales. To ascertain the moisture retentive power of a soil, put 10 grains of it, previously dried by exposure to a temperature of 212° (the boiling point of water), for half an hour, by having it laid upon c, whilst the water within it is kept boiling for that period. On the 10 grs. of

previously dried soil put, by means of a small quill, three drops of clean water; ascertain the exact weight of these, usually 4 grains; then suspend the beam, so that the pan of the scales containing the soil may rest upon c, as represented in the sketch, the weight of the water having previously been removed from the other scale-pan f. The water in c must be kept boiling, and the exact number of minutes noted that is required to evaporate the added moisture, so as to return the beam into equilibrium. It was by means of this apparatus that I obtained the comparative results detailed in a former volume. I have always found those soils proportionably unproductive, the first from containing too much alumina, and the second from a redundancy of silica, as they required more than 50 minutes, and less than 25 minutes, to deprive them of half their weight of moisture.

ease.

I shall now proceed to consider some of the diseases of plants, whose ravages affect the horticulturist, and on which science may afford some light. Plants being organised bodies, whose parts, in the common course of nature, are subject to waste and decay, the functions of these are consequently liable to disarrangement, and such disarrangement constitutes disSuch morbid affections are not, however, always the consequences of old age: they are often caused by matters being absorbed from the soil which are inimical to the constitution of the plant; from a want of those that are beneficial, as well as from their excess; from violent and sudden transitions of temperature; from wounds, and from the attacks of vermin. "Animals," said the late Dr. Good, "are liable, as we all know, to a great variety of diseases; so, too, are vegetables, to diseases as numerous, as varied, and as fatal; to diseases epidemic, endemic, sporadic; to scabies, pernio, ulcer, gangrene; to polysarcia, atrophy, and invermination. What

ever, in fine, be the system of nosology to which we are attached, it is impossible for us to put our hand upon any one class or order of diseases which they describe, without putting our hand, at the same time, upon some disease to which plants are subject in common with animals."

In previous communications upon the food and climate of plants, I have made a general statement of what may be termed their dietetics, in a treatise on vegetable pathology; and, as a due attention to those points is the best prevention of their diseases, I shall confine myself from any general remarks on that point, and to the specific diagnosis, prognosis, and treatment of such disorders as I may mention.

Canker, Ulcer. These are synonyms of the same disease, which is accompanied with different symptoms, according to the species of tree in which it occurs; being known as the canker in those whose true sap contains a more than usual proportion of acid; and as ulcer in those containing tannin, or other astringent principle. In both it is an ulcerous affection.

The symptoms vary in the genus Pyrus, and others whose sap contains a free acid. It is seldom, if ever, accompanied by a discharge; but the parts affected enlarge, their wood becomes brown and carious, and the bark covering them cracks, gapes, and manifests a disposition to separate from the wood. In the genera Ulmus, Quércus, and others abounding in astringent matters, a copious discharge usually accompanies all the preceding symptoms, which are always present also, with the exception of the swelling of the parts, which only occasionally occurs. The discharged liquid is occasionally transparent; but generally a reddish brown, becoming nearly black by exposure to the air. The sides of the ulcer, in the first instance, are usually covered with a white, crystalline, incrustation; in the second, with a shining, varnish-like coat. In the genus Prùnus, and others abounding with gum, the same symptoms are exhibited, except that swelling still more rarely occurs, and that the discharged matter is nearly pure gum, a variation which seems to remove it to another class of diseases. In every instance, I am prepared to maintain that the disease is local; that is, it at first arises from a disarrangement in the functions of the affected part, and is never brought on from a general diseased state of the tree; but is occasioned by contingencies perfectly independent of soil and situation. When the disease has commenced, if these are unfavourable, they may aggravate the symptoms, and promote their diffusion, but they are not the originators of the disease.

It appears to me, in general, to arise from contused wounds, however they may be inflicted; by the bruise occasioned by

a blow, or the erosion by a ladder, or the contact of two branches. The wounds in such cases, as in the animal frame, are long in healing; the extravasated sap and contused vessels speedily decompose: and how this spreads by contact, in all organised bodies, is too well known to need to be here insisted upon. The complete removal of the affected part by the knife, and then covering the wound by a plaster to exclude the air, is the best remedy; and if, from long neglect, it has been allowed to spread itself from branch to branch, until the whole tree has become infected, remedies are then of no avail, and the tree had better be removed.

The chemical phenomena of the disease appear to be the complete decomposition of the vegetable fibre, which passes off in the form of carbonic acid and carburetted hydrogen gases, whilst the friable matter which remains behind consists of some foreign vegetable principle, the result of decomposition, and an excess of saline and alkaline matters.

Vauquelin analysed the sanious discharge from an elm, and found in it nearly 40 per cent of alkaline and saline constituents, which is about three times as much as the sap contains when in a healthy state, if compared with the amount of its vegetable constituents. Then, again, the saline matter in the sap of the elm consists chiefly of acetate of potash and carbonate of lime: those in the sanious discharge, of carbonate of potash and carbonate of lime. Decomposition has here, therefore, been effected as well as in the carbonaceous matter of the tree a decomposition, too, aggravating the disease; for woody matter, macerated for some time in a solution of carbonate of potash, is decomposed and converted into ulmin: and that this effect is produced in the progress of the disease was demonstrated by Vauquelin, who found that the brown matter discharged by the elm consisted of ulmin and carbonate of potash.

Sir Humphry Davy detected carbonate of lime on the edges of the cankered parts of apple trees. The above facts demonstrate that an excess of alkaline matters occurs in vegetable ulcerations; and, guided by this, the last-named chemist recommended diluted acids to be applied to the wounds, and even poured about the roots, in case the tree is of sufficient value. The topical application would doubtless check the corrosion of the ulcer; but it admits of doubt whether the administering an acid to the roots would be of benefit, unless it were one that is not with facility decomposed, as the sulphuric, or muriatic: for, previously to arriving at the wound, it would have to be elaborated in organ which no vegetable acid, as the acetic or tartaric, would pass through unchanged. Muri