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of June and July. The following autumn the fruit growing on these trees came to great perfection, having ripened from a fortnight to three weeks earlier than usual : but in the succeeding spring, the vines did not shoot with their accustomed vigour, and I found that I had injured them by exposing the alburnum unne. cessarily.
Last summer these experiments were repeated ; at the end of July and beginning of August, I took annu. lar excisions of bark from the trunks of several of my vines, and that the exposed alburnum might be again covered with new bark by the end of autumn, the removed circles were made rather less than a quarter of an inch in width. Two vines of the white frontiniuc, in similar states of growth, being trained near to each other on a South wall, were selected for trial; one of these was experimented on (if I may use the term), the other was left in its natural state, to form a standard of comparison. When the circle of bark had been removed about a fortnight, the berries on the experimented tree began evidently to swell faster than those on the other, and by the beginning of September showed indications of approaching ripeness, while the fruit of the unexperimented tree continued green and small. In the beginning of October the fruit on the tree that had the bark removed from it, was quite ripe, the other only just began to show a disposition to ripen, for the bunches were shortly afterwards destroyed by. the autumnal frosts. In every case in which circles of bark were removed, I invariably found that the fruit not only ripened earlier, but the berries were considerably larger than usual, and more highly flavoured.
Vol. XIII.--SECOND SERIES. Dd The
The effects thus produced, I can account for only, by adopting Mr. Knight's theory of the downward circulation of the sap, the truth of which these experiments, in my opinion, tend strongly to confirm. I therefore imagine by cutting through the cortex and liber without wounding the alburnum, that the descent of that portion of the sap which has undergone preparation in the leaf is obstructed and confined in the branches situated above the incision; consequently the fruit is better nourished, and its maturation hastened. It is certainly a considerable point gained in the culture of the vine, to be able to bring the fruit to perfection, by a process so simple, and so easily performed. But lest there should be any misconception in the foregoing statement, I will briefly describe the exact method to be followed by any person, who may be desirous of trying this mode of ripening grapes. The best time for performing the operation on vines growing in the open air, is towards the end of July, or beginning of August; and it is a material point, not to let the removed circle of bark be too wide: from one to two-eighths of an inch will be a space of sufficient width; the exposed alburnum will then be covered again with new bark before the following winter, so that there will be no danger of injuring the future health of the tree. It is not of much consequence in what part of the tree the incision is made, but in case the trunk is very large, I should then recommend, that the circles be made in the smaller branches. It is to be observed that all shoots which come out from the root of the vine, or from the front of the trunk situated below the incision, must be removed as often as as they appear, unless bearing wood is particularly wanted to fill up the lower part of the wall, in which case one or two shoots may be left. Vines growing in forcing houses are equally improved in point of size and flavour, as well as made to ripen earlier by taking away circles of bark: the time for doing this, is when the fruit is set, and the berries are about the size of small shot. The removed circles may here be made wider than on vines growing in the open air, as the bark is sooner renewed in forcing-houses, owing to the warmth and moisture in those places. Half an inch will not be too great a width to take off in a circle from a vigorous growing vine, but I do not recommend the operation to be performed at all in weak trees. I think that this practice may be extended to other fruits, so as to hasten their maturity, especially figs, in which there is a most abundant flow of returning sap ; and it demonstrates to us, why old trees are more disposed to bear fruit than young ones. Miller informs us, that the vineyards in Italy are thought to improve every year by age, till they are fifty years old. It therefore appears to me, that nature, in the course of time, produces effects similar to what I have above recommended to be done by art. For, as trees become old, the returning vessels do not convey the sap into the roots, with the same facility they did when young : thus by occasionally removing circles of bark, we only anticipate the process of nature; in both cases a stagnation of the true sap is obtained in the fruiting branches, and the redundant nutriment then passes into the fruit. I have sometimes found that after the circle of bark has been removed, “a small portion of the inner bark . D d 2 has has adhered to the alburnum:” it is of the utmost importance to remove this, though ever so small, otherwise in a very short space of time, the communication is again established with the root, and little or no effect produced. Therefore in about ten days after the first operation has been performed, I generally look at the part from whence due bark was removed, and separate any small portion, which may have escaped the knife the first time. -
Description of a Capstan, which works without requiring the Messenger or Cable round it to be ever surged. By John WHITLEY Boswell, Esq.
With an Engraving,
From the TRANSACTIONS of the SocIETY for the Encou
ragement of ARTs, MANUFACTURES, and CoMMERCE.
The Gold Medal was presented to Mr. Boswell. for this - Invention.
As few but mariners understand the manner in which cables are hawled aboard in large ships, it will probably render the object of my capstan more manifest, to give some account of this operation.—Cables above a certain diameter are too inflexible to admit of being coiled round a capstan; in ships where cables of such large dimensions are necessary, a smaller cable is employed for this purpose, which is called the messenger, the two ends of which are made fast together so as to form an endless rope, which, as the capstan is turned out, revolves round it in unceasing succession, passing on its course to the head of the ship, and again returning to
• the capstan. To this returning part of the messenger
the great cable is made fast by a number of small ropes, called nippers, placed at regular intervals; these nippers are applied as the cable enters the hawse-hole, and are again removed as it approaches the capstan, after which it is lowered into the cable tier. The messenger, or any other rope coiled round the capstan, must descend a space at every revolution equal to the diameter of the rope or cable used ; this circumstance brings the coils in a few turns to the bottom of the capstan, when it can no longer be turned round, till the coils are loosened and raised up to its other extremity, after which the motion proceeds as before. This operation of shifting the place of the coils of the messenger on the capstan, is called surging the messenger: it always causes considerable delay; and when the messenger chances to slip in changing its position, which sometimes happens, no small danger is incurred by those who are employed about the capstan. The first method that I know of used to prevent the necessity of surging, was by placing an horizontal roller beneath the messenger, where it first entered on the capstan, so supported by a frame, in which it turned on
gudgeons, that the messenger in passing over it was
compelled to force upwards all the coils above the cap
stan, as it formed a new coil. This violent forcing of the coils upwards along the barrel of the capstan, not only adds considerably to the labour in turning the capstan, but from the great friction which the messenger must suffer in the operation while pressed so hard against the capstan, (as it must be by the weight of the anchor and strain of the men,) could not but cause a very great wear and injury to the messenger, or other cable wound round the capstap; and