each other, as when detached; and through this substance the ramifications of the vessels of the new bark extended themselves, appearing to receive their direction from the fluid sap, which descended from the bark of the young shoots, and not to be, in any degree, influenced in their course by the direction taken by the cortical and alburnous vessels of the preceding year. Whenever the vessels of the bark, which proceeded from Cortical vessels meeting form different points, met each other, an interwoven texture was an interwoven produced, and the alburnum beneath acquired a similar or- texture, ganization; and the same thing occurs, and is productive of very important effects, in the ordinary course of the growth teral branches, of trees. The bark of the principal stem, and of every la- Junction of lateral branch, contains very numerous vessels, which are charged with the descending true sap; and at the juncture of the lateral branch with the stem, these vessels meet each other. A kind of pedestal of alburnum, the texture of which is much interwoven, is in consequence formed round the base of the lateral branch; which thus becomes firmly united to the tree. This pedestal, though apparently a part of the branch, derives a large portion of the matter, annually added to it, from the cortical vessels of the principal stem; and thence, in the event of the death of the lateral branch, it always continues to live. But it not unfrequently happens, Weak when that a lateral branch forms a very acute angle with the forming a very acute angle, principal stem, and, in this case, the bark between them becomes compressed and inactive; no pedestal is in consequence formed, and the attachment of such a branch to the stem becomes extremely feeble and insecure. Instead of •The advantages, which may be obtained by pruning timber trees ju- Advantages of diciously, appear to be very little known. I have endeavoured to as- properly pruning and traincertain the practicability of giving to trees such forms as will render their ing timber timber more advantageously convertible to naval or other purposes. trees. The success of the experiments, on small trees, has been complete, and the results perfectly consistent, in every case, with the theory I have endeavoured to support in former memoirs; and I am confident, that by appropriate management, the trunks and branches of growing trees may be moulded into the various forms best adapted to the use of the shipbuilder; and that the growth of the trees may at the same time be rendered considerably more rapid, without any expense or temporary loss to the proprietor. Theory. Bark sometimes exists previous to the albumum. the reproduced buds of the preceding experiment, buds were inserted in the foregoing summer, or attached by grafting in the spring; and, when these succeeded, though they were in many instances taken from trees of different species, and even of different genera, no sensible difference existed in the vessels, which appeared to diverge into the bark of the stock, from these buds and from those reproduced in the preceding experiments. It appears, therefore, probable, that a pulpous organizable mass first derives its matter either from the bark, or the alburnum; and that this matter subsequently forms the new layer of bark; for, if the vessels had proceeded, as radicles, from the inserted buds or grafts, such vessels would have been in some degree different from the natural vessels of the bark of the stocks; and it does not appear probable, even without referring to the preceding facts, that vessels should be extended, in a few days, by parts successively added to their extremities, from the leaves to the extremities of the roots; which are, in many instances, more than two hundred feet distant from each other. I am, therefore, inclined to believe, that, as the preceding facts seem to indicate, the matter, which composes the new bark, acquires an organization calculated to transmit the true sap towards the roots, as that fluid progressively descends from the leaves in the spring; but whether the matter, which enters into the compo. sition of the new bark, be derived from the bark or the alburnum, in the ordinary course of the growth of the tree, it will be extremely difficult to ascertain. It is, however, no difficult task to prove, that the bark does not, in all cases, spring from the alburnum; for many cases may be adduced, in which it is always generated previously to the existence of the alburnum beneath it; but none, I believe in which the external surface of the alburnum exists previously to the bark in contact with it, except when the cortical substance has been taken off, as in the preceding experiments. In the radicle of germinating seeds, the cor tical vessels elongate, and new portions of bark are succes. Darwin's Phytologia. sively added to their points, many days before any alburnous substance is generated in them; and in the succulent annual shoot the formation of the bark long precedes that of the alburnum. In the radicle the sap appears also evidently to descend through the cortical vesselst, and in the succulent annual shoot it as evidently passes up through the central vessels, which surround the medulla. In both cases a cellular substance, similar to that which was generated in the preceding experiments, is first formed, and this cellular substance in the same manner subsequently becomes vascu▾ lar; whence it appears, that the true sap, or blood of the plant, produces similar effects, and passes through similar stages of organization, when it flows from different sources, and that the power of generating a new bark, properly speaking, belongs neither to the bark nor alburnum, but to a fluid, which pervades alike the vessels of both. burnum. I shall, therefore, not attempt to decide on the merits of Bark not trans. the theory of Malpighi, or of Hales, respecting the reproduc- muted into altion of the interior bark; but I cannot by any means admit the hypothesis of Malpighi and other naturalists, relative to the trasmutation of bark into alburnum; and I propose to state my reasons for rejecting that hypothesis, in the next communication I have the honour to address to you, I am, my dear Sir, Your most obliged obedient Servant, Elton, Dec. 18, 1806. T. A. KNIGHT. Phil. Trans. 1805 and 1806, or Philos. Journal, vol. XIII and XVI. + I wish it to be understood, that I exclude in these remarks, and in those contained in my former Memoirs, all trees of the palm kind, with the organization of which I am almost wholly unaccquainted. Phil. Trans. 1805. Mirbel has called the tubes, which I call the central vessels, the "tissu tubulaire" of the medulla. II. On the Economy of Bees. In a Letter from THOMAS AN- MY DEAR SIR, IN the prosecution of those experiments on trees, accounts of which you have so often done me the honour to present to the Royal Society, my residence has necessarily been almost wholly confined to the same spot; and I have thence been induced to pay considerable attention to the economy of bees, amongst other objects; and as some interesting circumstances in the habit of these singular insects appear to have come under my observation, and to have escaped the notice of former writers, I take the liberty to communicate my observations to you. It is, I believe, generally supposed, that each hive, or swarm, of these insects remains at all times wholly unconnected with other colonies in the vicinity; and that the bee never distinguishes a stranger from an enemy. The circumstances which I shall proceed to state will, however, tend to prove, that these opinions are not well founded, and that a friendly intercourse not unfrequently takes place between different colonies, and is productive of very important consequences in their political economy. Passing through one of my orchards rather late in the evening in the month of August, in the year 1801, I observed, that several bees passed me in a direct line from the hives in my own garden to those in the garden of a cottager, which was about a hundred yards distant from it. As it was considerably later in the evening than the time when bees usually cease to labour, I concluded, that something more than ordinary was going forward. Going first to my own cottager, I found a very garden, and then to that of the considerable degree of bustle and agitation to prevail in one hive in each every bee, as it arrived, seemed to be stopped Philos. Trans. for 1807, Part II, p. 234. and and questioned, at the mouth of each hive; but I could not discover any thing like actual resistance, or hostility, to take place; though I was much inclined to believe the intercourse between the hives to be hostile and predatory. The same kind of intercourse continued, in a greater or less degree, during eight succeeding days, and though I watched them very closely, nothing occurred to induce me to suppose, that their intercourse was not of an amicable kind. On the Ended in a tenth morning, however, their friendship ended, as sudden quarrel. and violent friendships often do, in a quarrel; and they fought most furiously; and after this there was no more vi siting. Two years subsequent to this period I observed the same Similar interkind of intercourse to take place between two hives of course between my two other own bees, which were situate about two hundred yards dis- hives. tant from each other; they passed from each hive to the other just as they did in the preceding instance, and a simi lar degree of agitation was observable. In this instance, however, their friendship appeared to be of much shorter Quarrelled on duration, for they fought most desperately on the fifth day; the fifth day. and then, as in the last mentioned case, all further visiting ceased, I have some reason to believe, that the kind of intercourse Sometimes I have described, which I have often seen, and which is by two swarms form a juncno means uncommon, not unfrequently ends in a junction tion, of the two swarms; for one instance came under my observation, many years ago, in which the labouring bees, under circumstances perfectly similar to those I have described, wholly disappeared, leaving the drones in peaceable posses sion of the hive, but without any thing to live upon. I have also reasons for believing, that whenever a junction of two swarms, with their property, is agreed upon, that which proposes to remove, immediately, or soon afterward, unites with the other swarm, and returns to the deserted hive during the day only to carry off the honey: for having examined at night a hive from which I suspected the bees to be migrat ing, I found it without a single inhabitant. I was led to make the examination by information I had received from a very accurate observer, that all the bees would then be ab sent. A very considerable quantity of honey was in this in stance |