Another important advantage derived by the spider from the multiplicity of its threadlets is, that the thread affords a much more secure attachment to a wall, a branch of a tree, or any other object, than if it were simple; for, upon pressing the spinneret against the object, as spiders always do when they fix a thread, the spinnerules are extended over an area of some diameter, from every hair’s breadth of which a strand, as rope-makers term it, is extended to compound the main cord. Fig. 11. Plate IV. exhibits, magnified, this ingenious contrivance. Those who may be curious to examine it, will see it best when the line is attached to any black object, for the threads, being whitish, are, in otherwise, not so easily perceived. SHOOTING OF THE LINES.--It has long been considered a curious though difficult investigation, to determine in what manner spiders, seeing that they are destitute of wings, transport themselves from tree to tree, across brooks, and frequently through the air itself, without any apparent starting point. On looking into the authors who have treated upon this subject, it is surprising how little there is to be met with that is new, even in the most recent. Their conclusions, or rather their conjectural opinions, are, however, worthy of notice; _for by unlearning error, we the more firmly establish truth_. 1. One of the earliest notions upon this subject is that of Blancanus, the commentator on Aristotle, which is partly adopted by Redi, by Henricus Regius of Utrecht, by Swammerdam[145], by Lehmann, as well as by Kirby and Spence[146]. “The spider’s thread,” says Swammerdam, “is generally made up of two or more parts, and after descending by such a thread, it ascends by one only, and is thus enabled to waft itself from one height or tree to another, even across running waters; the thread it leaves loose behind it being driven about by the wind, and so fixed to some other body.” “I placed,” says Kirby, “the large garden spider (_Epeira diadema_) upon a stick about a foot long, set upright in a vessel containing water.... It let itself drop, not by a single thread, but by _two_, each distant from the other about the twelfth of an inch, guided, as usual, by one of its hind feet, and that one apparently smaller than the other. When it had suffered itself to descend nearly to the surface of the water, it stopped short, and by some means, which I could not distinctly see, broke off, close to the spinners, the smallest thread, which still adhering by the other end to the top of the stick, floated in the air, and was so light as to be carried about by the slightest breath. On approaching a pencil to the loose end of this line, it did not adhere from mere contact. I, therefore, twisted it once or twice round the pencil, and then drew it tight. The spider, which had previously climbed to the top of the stick, immediately pulled at it with one of its feet, and finding it sufficiently tense,