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Rh the best form for a speaking trumpet. Lambert, in the Berlin Memoirs for 1763, seems to have been the first to give a theory of the action of this instrument, based on an altogether imaginary analogy with the behaviour of light. In this theory, which is still commonly put forward, it is assumed that sound, like light, can be propagated in rays. This, however, is possible only when the aperture through which the wave-disturbance passes into free air is large compared with the wave-length. If the fusiform mouth of the speaking trumpet were half a mile or so in radius, Lambert’s theory might give an approximation to the truth. But with trumpets whose aperture is only a foot in diameter at the most the problem is one of diffraction.

In the hearing trumpet, the disturbance is propagated along the converging tube much in the same way as the tide-wave is propagated up the estuary of a tidal river. In speaking and hearing trumpets alike all reverberation of the instrument should be avoided by making it thick and of the least elastic materials, and by covering it externally with cloth. (See .)  TRUMPETER, or, the literal rendering in 1747, by the anonymous English translator of De la Condamine’s travels in South America (p. 87), of that writer’s “Oiseau trompette” (Mém. de l’Acad. des Sciences, 1745, p. 473), a bird, which he says was called “Trompetero” by the Spaniards of Maynas on the upper Amazons, from the peculiar sound it utters. He added that it was the “Agami” of the inhabitants of Para and Cayenne, wherein he was not wholly accurate, since those birds are specifically distinct, though, as they are generically united, the statement may pass. But he was also wrong, as had been P. Barrère (France equinoxiale, p. 132) in 1741, in identifying the “Agami” with the “Macucagua” of Marcgrav, for that is a (q.v.); and both still more wrongly accounted for the origin of the peculiar sound just mentioned, whereby Barrère was soon after led (Ornith. Spec. Novum, pp. 62, 63) to apply to the bird the generic and vulgar names of Psophia and “Petteuse,” the former of which, being unfortunately adopted by Linnaeus, has ever since been used, though in 1766 and 1767 Pallas (Miscellanea, p. 67, and Spicilegia, iv. 6), and in 1768 Vosmaer (Descr. du Trompette Américain, p. 5), showed that the notion it conveys is erroneous. Among English writers the name “Trumpeter” was carried on by Latham and others so as to be generally accepted, though an author may occasionally be found willing to resort to the native “Agami,” which is that almost always used by the French.

P. L. Sclater and O. Salvin in their Nomenclator (p. 141) admit 6 species of Trumpet-Birds: (1) the original Psophia crepitans of Guiana; (2) P. napensis of eastern Ecuador (which is very likely

the original “Oiseau trompette” of De la Condamine); (3) P. ochroptera from the right bank of the Rio Negro; (4). P. leucoptera from the right bank of the upper Amazons; (5) P. viridis from the right bank of the Madeira; and (6) P. obscura from the right bank of the lower Amazons near Para. And they have remarked in the Zoological Proceedings (1867, p. 592) on the curious fact that the range of the several species appears to be separated by rivers, a statement confirmed by A. R. Wallace (''Geogr. Distr. Animals'', ii. 3258); and in connexion therewith, it may observed that these birds have short wings and seldom fly, but run, though with a peculiar gait, very quickly. A seventh species P. cantatrix, from Bolivia, has since been indicated by W. Blasius (''Journ. f. Ornith.'', 1884, pp. 203–210), who has given a mono graphic summary of the whole group very worthy of attention. The chief distinctions between the species lie in colour and size, and it will be here enough to describe briefly the best known of them, P. crepitans. This is about the size of a large barndoor fowl; but its neck and legs are longer, so that it is a taller bird. The head and neck are clothed with short velvety feathers: the whole plumage is black, except that on the lower front of the neck the feathers are tipped with golden green, changing according to the light into violet, and that a patch of dull rusty brown extends across the middle of the back and wing-coverts, passing into ash-colour lower down, where they hang over and conceal the tail. The legs are bright pea-green. The habits of this bird are very wonderful, and it is much to be wished that fuller accounts of them had appeared. The curious sound it utters, noticed by the earliest observers, has been already mentioned, and by them also was its singularly social disposition towards man described; but the information supplied to Buffon (Oiseaux, iv. 496–501) by Manoncour and De la Borde, which has been repeated in many works, is still the best we have of the curious way in which it becomes semi-domesticated by the Indians and colonists and shows strong affection for its owners as well as for their living property—poultry or sheep—though in this reclaimed condition it seems never to breed. Indeed nothing can be positively asserted as to its mode of nidification; but its eggs, according to C. E. Bartlett, are of a creamy white, rather round, and about the size of bantams’. C. Waterton in his Wanderings (Second Journey, chap. iii.) speaks of falling in with flocks of 200 or 300 “Waracabas,” as he called them, in Demerara, but added nothing to our knowledge of the species; while the contributions of Trail (Mem. Wern. Society, v. 523–532) and as Dr Hancock (Mag. Nat. History, 2nd series, vol. ii. pp. 490–492) as regards its habits only touch upon them in captivity.

To the trumpeters must undoubtedly be accorded the rank of a distinct family, Psophiidae; but like so many other South-American birds they seem to be the less specialized descendants of an ancient generalized group—perhaps the common ancestors of the Rallidae and Gruidae. The structure of the trachea, though different from that described in any (q.v.), suggests an early form of the structure which in some of the Gruidae is so marvellously developed, for in Psophia the windpipe runs down the breast and belly immediately under the skin to within about an inch of the anus, whence it returns in a similar way to the front of the sternum, and then enters the thorax. Analogous instances of this formation occur in several other groups of birds not at all allied to the Psophiidae.

 TRUNK (Fr. tronc, Lat. truncus, cut off, maimed), properly the main stem of a tree from which the branches spring, especially the stem when stripped of the branches; hence, in a transferred sense, the main part of a human or animal body without the head, arms or legs. It is from this last sense that the term “trunk-hose” is derived. These were part of the typical male costume of the 16th century, consisting of a pair of large puffed and slashed over-hose, reaching from the waist to the middle of the thigh, the legs clad in the long hose being thrust through them; the upper part of the body was covered by the jerkin or jacket reaching to the thigh (see ). The word “trunk” as applied to the elongated proboscis of the elephant is due to a mistaken confusion of French trompe, trump, with “trunk” meaning the hollow stem of a tree. A somewhat obscure meaning of French tronc, i.e. an alms-box, has given rise to the general use of “trunk” for a form of travellers’ luggage.  TRURO, THOMAS WILDE, (1782–1855), lord chancellor of England, was born in London on the 7th of July