years it entirely covered by its own runners, without any fresh plants being put in, and this bed, with the addition of some hanging boxes receding from the centre to the sides, produced, in the year 1806, 23 bottles of very fine cranberries.

In the year 1805, a bed was made on the side of the pond 20 feet long and 5 feet broad, by a few stakes driven into the bottom parallel to the side, and lined with old boards; the bottom of this was filled up with stones and rubbish, and on these a bed of black mould, 3 inches above and 7 inches below the usual surface of the water, was laid this was planted with cranberry plants, many of them having been rooted in a hot-bed, in which they throve most vigorously. In this autumn, 1807, the bed produced a crop which, added to that of the island, afforded a supply for the family, of 5 dozen bottles of cranberries besides a small basket reserved

for present use. The total contents of the two cranberry beds, is 326 square feet; the quantity of land employed for raising strawberries at Spring Grove, is, after the divisions between the beds have been deducted, 5645 square feet; the beds necessary to give a sufficient supply of cranberries for the family, did not therefore occupy quite one-eighth of the space allotted to strawberries.

The Society will, I hope, forgive this detail of the origin and progress of this kind of cultivation: successful as it has been, it must still be considered in its infancy, and not sufficiently established to afford general rules for the regulation of a gardener's proceedings: it originated entirely in a fortunate accident, the history of which, will, it is hoped, give an adequate idea of the method now practised, and at the same time bear testi

mony

mony in favour of the opinion, that more benefit has been derived in the advancement of Horticultural knowledge, by pursuing the hints which Nature continually gives, than from the effects of abstract reasoning and original invention.

It is remarkable that, during the seven years these cranberries have been cultivated at Spring Grove, no circumstance has arisen, from the variety of seasons, from blight, or any other circumstance, that has diminished the quantity of a full crop; the flowers have issued out of their buds, in abundance, in their due season, and fewer of them have been abortive, than in general is the case in other plants. The fruit has gradually swelled and duly ripened without being subject to the attack of any vermin, or to injuries of any kind from the excesses of heat or cold, or from those of wetness or of drought.

Observations on the Means of giving to the Wheels of heavy Carriages the same Intensity of Pressure on the Surface of Roads; and a Statement of the Advantages that would result therefrom.

By ALEXANDER CUMMING, Esquire, of Pentonville.

(From the APPENDIX to the REPORTS of the COMMITTEE of the HOUSE OF COMMONS on the Highways of the Kingdom.)

1. ADMITTING that the cylindrical wheel was universally adopted, it becomes of the greatest importance that the breadth of the wheels be adjusted to the weight of the load; so that the track or impression of the wheels of every carriage shall be of the same depth, and that

the

the wheels of each carriage may reciprocally roll in or upon the tracks of each other without damage; but that on the contrary each subsequent wheel shall add to the improvement of the preceding, and render the track more perfect than before,

2. There appears to have been a great oversight in the regulations of the 13th of Geo. III. in this respect. The weight of the loaded waggon being divided into four, and each wheel supposed to bear an equal share, the total pressure of the wheels on the road appears to have been taken as the effective power of the wheel to act and make an impression on the surface; and no other criterion of the intensity of that power to cut the surface, or to make an impression or rut was assumed; no notice appears to have been taken of the proportion which the breadth of the wheel had to the weight that it sustained; nor of the intensity of the action of the same weight on wheels of different breadths.

3. By this manner of estimating the effective power, or the intensity of the force, with which the wheel compresses the surface which it rolls, one should be led to many erroneous conclusions; the intensity of the pressure of the wheel would always be supposed to depend wholly on the weight of the load, whatever might be the breadth of the wheel; and by that rule, the intensity of action of the 16-inch wheel with the load of eight ton would be to the intensity of the wheel of three inches, and the load of 3 ton, as 4,480 to 1,960; and this would seem a pretty fair proportion between the weight of the load and the breadth of the wheels, at least it is so fair in appearance, that the heaviest load has the greatest intensity.

VOL. XIII. -SECOND SERIES.

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4. Nothing can be more certain than that increasing the breadth of the wheel diffuses the pressure on a larger surface, and diminishes the intensity of that pressure on every inch of the surface that is rolled; let us then examine and compare the intensity of pressure of the 16inch wheel, and the three-inch wheel, with the loads as before, making allowance for the breadth of each of the wheels; and the intensity of the pressure on every inch that is rolled by the 16-inch wheel with the load of eight ton, will be equal only to the dead weight of 280 lb. The intensity of the pressure of the three-inch wheel with the load of 3 ton is equal to 653 lb., which is considerably more than twice the intensity of the pressure with the 16-inch wheel. This shews how little attention has been paid to the real advantages of the broad wheel, and the disadvantages of the narrow; and proves the necessity of such new regulations, as shall render the intensity of the pressure of all wheels, and with different loads, on the surface of the roads, equal to each other, so that every wheel shall make an impression or track of the same depth.

5. The following table is according to the 13th of Geo. III. The three first columns give the breadth of the wheels, the weight of the load, and the number of horses, as stated in that Act; the fourth column gives the weight drawn by each horse; the fifth gives the weight on each wheel, or the total pressure, whatever be the breadth of the wheel; and the sixth column gives the pressure on every inch of the breadth of the wheel, or the true intensity of the pressure on the surface of the road, according to the breadth of each wheel.

7. It appears by this table that no regular proportion has been observed between the breadth of the wheels, the weight of the load and the number of horses; in the fifth column the sum of the pressure on the wheel decreases pretty gradually as the wheels become narrower ; but in the sixth column, where the breadth of the wheel is taken into the account, the intensity of the pressure on every inch of the surface that is rolled, is increased as the wheels become narrower, which seems contrary to all reason.

8. With the nine-inch and the six-inch wheels, when they roll a double surface, the weight of the load is con siderably increased, although the resistance to the progress of the wheels, and the labour of the cattle, with the same load, is increased by rolling the double surface.

9. If the roads be in good order, the double rolling is of no use; if they be soft and compressible, the resistance becomes greater, as the surface that is rolled is broader; and it is generally supposed, that the resistance in rolling the double surface is the same as with the single; but it ought to be remembered that with the single surface the hind wheels run in the paved track of