eyes towards heaven and observes the clouds and answers the band around him. They all raise their eyes towards heaven, observe the clouds, and hurl spells against the elements, so that they arouse strife amongst them and clouds of fire are driven towards the camp of the men of Ireland.” We are further told that at the court of Conchobar no one had the right to speak before the Druids had spoken. In other texts the Druids are able to produce insanity.
In the religious literature they are almost exclusively represented as magicians and diviners opposing the Christian missionaries, though we find two of them acting as tutors to the daughters of Laegaire, the high-king, at the coming of St Patrick. They are represented as endeavouring to prevent the progress of St Patrick and St Columba by raising clouds and mist. Before the battle of Culdremne (561) a Druid made an airbe drúad (fence of protection?) round one of the armies, but what is precisely meant by the phrase is obscure. The Irish Druids seem to have had a peculiar tonsure. The word drúi is always used to render the Latin magus, and in one passage St Columba speaks of Christ as his Druid.
See D’Arbois de Jubainville, Les Druides et les dieux celtiques à forme d’animaux (Paris, 1906), and Introduction à l’étude de la littérature celtique (Paris, 1883); P. W. Joyce, A Social History of Ancient Ireland (London, 1903). (E. C. Q.)
DRUIDS, ORDER OF, a friendly society founded, as an imitation of the ancient Druids, in London in 1781. They adopted Masonic rites and spread to America (1833) and Australia. Their lodges are called “Groves.” In 1872 the Order was introduced into Germany. (See Friendly Societies.)
DRUM (early forms drome or dromme, a word common to many Teut. languages, cf. Dan. tromme, Ger. Trommel: the word is ultimately the same as “trumpet,” and is probably onomatopoeic in origin; it appears late in Eng. about the middle of the 16th century), the name given to the well-known musical instrument (see below) and also to many objects resembling it in shape. Thus it is used of any receptacle of similar shape, as a “drum” of oil, &c.; in machinery, of a revolving cylinder, round which belting is passed; of the tympanum or cylindrically shaped middle ear, and specially of the membrane that closes the external auditory meatus; and, in architecture, of the substructure of a dome when raised to some height above the pendentives. The architectural drum had a twofold object; first, to give greater elevation to the dome externally so that it should rise well above the surrounding building, and secondly, to allow of the interior being lighted with vertical windows cut in the drum, instead of forming penetrations in the dome itself, as in St Sophia, Constantinople. The term is also applied to the circular blocks of stone, which in columns of large dimensions were built with a series of drums. At Selinus in Sicily some of these great circular blocks are found on the road between the quarries and the temples; they vary from 8 to 10 ft. in diameter, being about 6 ft. high. The term frusta is sometimes applied to them.
In music the drum (Fr. tambour; Ger. Trommel; Ital. tamburo) is an instrument of percussion common in some form to all nations and ages. It consists of a frame or vessel forming a resonant cavity, over one or both ends of which is stretched a skin or vellum set in vibration by direct percussion of hand or stick. Drums fall into two divisions according to the nature of their sonority:—(1) instruments producing sounds of definite musical pitch, and qualified thereby to take part in the harmony of the orchestra, such as the kettledrum (q.v.); (2) instruments of indefinite sonorousness, and therefore excluded from the harmony of the orchestra; such are the bass drum, the side or snare drum, the tenor drum, the tambourine, all used for marking the rhythm and adding tone colour.
Drums are further divided into three classes according to special features of construction:—(1) instruments having a skin stretched over one end of the resonant cavity, the other being open, such as the tambourine (q.v.) and the darabukkeh or Egyptian drum, shaped like a mushroom; (2) instruments consisting of a cup-shaped receptacle of metal, wood or earthenware entirely closed by a skin or vellum stretched across the opening, as in the kettledrum; (3) a receptacle in the shape of a cylinder closed at both ends by skins, as in the bass drum, side drum, &c.
Skin or parchment only acquires the elasticity requisite to produce vibration by tension; the vibrations of the parchment are taken up by the air enclosed in the receptacle, which thus reinforces the sound produced by the parchment. The tone of the instrument whether definite or indefinite depends upon the dimensions of the vellum, the shape of the resonant receptacle, and the method of percussion. The intensity of the sound depends upon the degree of percussive force used and the diameter of the vellum in proportion to the dimensions of the resonant receptacle; the material of which the latter consists has little or no influence on the tone of the instrument. The pitch of the sound is determined by the dimensions of the vellum taken in conjunction with the degree of tension, the pitch varying in acuteness directly with the degree of tension and inversely with the size of the vellum.
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| Fig. 1.—Military Bass Drum (Besson & Co.) |
The bass drum or Turkish drum (Fr. grosse caisse; Ger. Grosse Trommel; Ital. gran cassa or tamburo grande) consists of a short cylinder of very wide diameter covered at both ends by vellum stretched over thin hoops, which in turn are kept in place by larger hoops fitting tightly over them. At regular intervals in the two large hoops are bored holes through which passes an endless cord stretched in zig-zag round the cylinder and connecting the two hoops. The tension of the vellum is controlled by means of leather braces which are made to slide up and down the zig-zag of cord, slackening or tightening the large hoops, and with them the vellum, at the will of the performer. Systems of rods and screws are also used for the purpose. The bass drum is mounted on a stand when used in the orchestra. The sound is produced by striking the centre of the vellum on the one end of the drum with a stick having a large soft round knob composed of wood covered with cork, sponge or felt. The bass drum cannot be tuned since it gives out no definite note, but the pitch may be varied, according as a rich full tone or a mere dull thud be required, by tightening or loosening the braces; the instrument can, moreover, be muffled by covering it with a piece of cloth. The music for the bass drum is generally written on a stave with a bass clef, 
, the C being merely used to show the rhythm and accents. Sometimes the stave is dispensed with, a single note on a single line being sufficient. The bass drum has a place in every orchestra, although it is used but sparingly to accentuate the rhythm. It is possible to make gradations in forte and piano on the bass drum, and to play quavers and semi-quavers in moderate tempo. A roll is sometimes played by holding a short stick, furnished with a knob at each end, in the middle and striking in quick succession with each knob alternately; two kettledrum sticks answer the purpose still better. It is understood that the cymbals play the same music as the bass drum unless the composer has written senza piatti over the part. Wagner did not once score for the bass drum after he composed Rienzi, but Verdi, Gounod, Berlioz and Sullivan used it effectively. The bass drum was formerly known as the long drum, the cylinder being long in proportion to the diameter.
The side or snare drum (Fr. tambour militaire; Ger. Militärtrommel; Ital. tamburo militare) is an instrument consisting of
