years, and of which I have enquired of gardeners and others, without learning any thing material relating to it.

"In a green-house, attached to my residence at Hackney, in the year 1809, I planted forty-four vines, of various descriptions, inside the house. They grew vigorously the first year, and produced famous shoots, and they were pruned in the autumn of the same year; looking, as I did, in the spring of 1810, for a tolerable crop of fruit: the buds of the vines began to swell, but scarcely produced a shoot, and those only of the weakest description. Concluding that something was wrong at the roots, I examined one, and found that the roots had been completely eaten off by an insect resembling fig. 67. A, in p. 158. of your communication, in very large quantities; some of them were similar to fig. 67. D, in p. 158., and a short time after some appeared on the vines similar to fig. 67. G, in their perfect state; appearing first, when young and at coming out of the ground, of a pale ash colour, and afterwards becoming darker, and nearly black.

"About eighteen years since I came to my present residence, and have been constantly annoyed by the same insect, to a greater or less extent. If I find my vines drooping, either in the border or in pots, I invariably find the grub, fig. 67. D, above referred to, at the roots. The grubs come out of the ground in May, and then feed on the tendrils, or footstalks, of the leaves, or the extreme ends of the shoots of the vine. They are scarcely ever found in the day, but are very active after dark, always disappearing before daybreak.

66

"I have been in constant consultation with my gardener, an able man, who has been with me many years, respecting this insect, but we can hit on no method of destroying it. We have found it in abundance in the root of the Cyclamen pérsicum; and we have lately lost a fine plant of the Adiantum pedatum, in consequence of its ravages. I now and then find a straggler on the vines on the walls, and on other trees; and, occasionally, we find many of the old roots of the strawberry destroyed by the same insect.

"I should observe that it seldom does much damage to vines after the first or second year; and that it confines itself mostly to the young vines newly planted, or to vines in pots. My gardener has never found it on the roots of succulent plants.

"I send you some of the insects in a tin box; also some of another description, which I constantly find on the vines; but these last do not appear to do any mischief..

"If you could point out any mode of destroying them, you would be doing a favour to,

"Sir, your very obedient servant,

"WM. LINWOOD.

It will be seen that Mr. Linwood's communication furnishes a reply to my query, in p. 287., relative to the place of abode of the larvæ of the perfect individuals which attack the vines and other wall trees. It will, also, be seen, that J. B. W.'s note is partially at variance with the observations of Mr. Linwood; viz., that the insect seldom does much damage to the vines after the first or second year. In case of the attacks of the Otiorhynchi upon the vines or peaches, it would, I should think, be serviceable not only to water the roots known or suspected to be infested with the larvæ, with tobacco water or infusion of quassia, or some such bitter fluid, but also occasionally to lay bare the roots to a short distance, and examine if the insect is present. This can, of course, be done with much greater facility with vines than with succulent plants; although I see no great difficulty even with the latter.

The other insects sent by Mr. Linwood were specimens of one of the species of Elatérida; the larva of which are very injurious to cultivators, and are known under the name of wire worms. These will form the subject of an early article in my series. I am, &c.,

June 12. 1837.

J. O. WESTWOOD.

ART. III. Remarks on Tile-Draining, and on certain Benefits which might result from the Use of Draining Tiles in supplying Air to the Subsoil. By ROBERT ARTHUR, Gardener at Wall Tower Gardens, North Berwick.

DRAINING by means of tiles may justly be reckoned one of the greatest improvements in modern agriculture; nor are all the purposes to which tile-draining may be applied, as yet fully ascertained.

Without going into detail as to the amelioration of the soil, &c., by tile drains, I would merely suggest that it has occurred to me, that the tunnels formed by drain-tiles might be employed for at least one purpose besides drying the soil, I mean the introduction of large quantities of atmospheric air into the earth, which might be a means of saving manure and increasing the fertility of the soil. Should the idea now thrown out be deemed worthy of consideration, I think I could point out a method by which the confined air could be withdrawn from these tunnels, and large quantities of atmospheric air forced in, which would find its way towards the surface. One objection to tile-draining is the great outlay of capital it occasions: this there is every reason to hope is in a fair way of being greatly reduced. The Marquess of Tweeddale has succeeded in constructing a machine which, from the facility and expedition with which it forms the most beautiful and substantial bricks and tiles, cannot fail to re

duce the prime cost of these articles very considerably. Without any pretensions to give an accurate description of this machine, which could not be done without drawings, it may suffice to say that the clay is conveyed from the pug-mill to the machine, where, by passing between cylinders and moving over moulds, a tile of perfect consistency and proper dimensions is formed, and conveyed along to the drying shed, without the intervention of manual labour. Several of these machines are now in full operation; and, with the attendance of one man and two boys, 10,000 tiles are easily formed and placed in the drying sheds in one day. If the duty were reduced on large-sized bricks it would add much to the cheapness, strength, and beauty of brick building generally. How easy would it be to form excellent coping for garden walls, edgings for gravel walks, movable walls for the protection of early potatoes, peas, &c., and paving for fruit-tree borders, and for training fruit-trees near the surface of the ground. East Lothian, May 26. 1837.

ART. IV. Description of Hogg's Patent conical Boiler, for heating Hot-houses, and other Buildings, by hot Water. By JAMES HOGG, New York, United States.

I FORWARD to you two sketches of a boiler invented by my brother, now residing in New York, who is but eighteen years of age, and who, as I was coming on a visit to this country, desired me to give you a description of it, for insertion in the Gardener's Magazine.

The boiler is intended for burning anthracite coal (which is now most generally used in the United States) or coke. Anthracite coal gives out a most intense heat, but it is not diffusive enough in a flue, as it has no smoke, and very little flame; and, consequently, owing to the severity of the American winters, we are obliged to use great quantities of it, which causes much wear and tear of the furnaces, which generally want repairing every season, and resetting at least every two years. To obviate this expense, and to do away with the trouble of attending flues, my brother, from a hint given him by my father, invented the boiler above described. Its principal merit is, that there is very little loss of heat, nearly all of it being absorbed by the water which passes round the pipes and furnace. The outside, being of strong. oak staves, is much cheaper than iron, and nearly as durable; and there is no leakage, warping, or danger from fire, as the furnace is raised, by means of the ring, at least two inches above the iron plate.

Fig. 104. is a section of the boiler, which consists of a conical iron furnace a a, with the two pipes b and c, and the flanges d d,

cast in one piece, to which the outside boiler, made of wooden staves, is fitted, and well bound with iron hoops. The whole stands on a square iron plate (e e), supported by the brickwork of the ashpit (ƒ); and, from the top of this plate, the ring g g rises and fits into a bead on the bottom of the furnace. In this ring there are two pins; the one is shown at h on which the grate turns, and at there is a hole through which the other pin () passes, and supports the grate.

The fuel is put in at the top of the pipe c, and receives air from the front of the ashpit, which has a register door, as shown by the elevation (fig. 105.); the draught passing up the pipe b (fig. 104.), in which there is a damper (1). The two water-pipes (mm) are fastened on either by bolts or screws, and they can be made to lead from the boiler either horizontally, or perpendicularly; as shown by the elevation fig. 105. n is an expansion

feeding-pipe with a stop-cock; o is a stop-cock for drawing off the water from the boiler when it is not in use; p is a lid which fits on to the fuel pipe (c.) The dimensions are as follows: The height of the furnace from g to r is 18 in. The height of the pipes c and d, from r to s, is 9 in. The diameter of the pipes c and d is 4 in. The diameter of the furnace, at the bottom, is 14 in.; and at the top 12 in. The upper flange is 5 in. wider; and the lower flange is 2 in. wider. The staves are 2 ft. 6 in. high.

There is very little heat lost in the pipes b and c, for the water absorbs it so fast, that a person may hold his hand on them without feeling the least inconvenience. The boiler can be used hermetically sealed, by closing the pipe n; but this should not be done unless the outside is extra-hooped.

When the fire is put out, the ashes are removed by pulling out the pin k, when the grate falls down and empties itself into the ashpit. The grate is easily replaced by opening the door, raising it up, and replacing the pin. The poker used for this