Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/763

Rh O B O O B O 705 operative part of a bond. The third use of the word is chiefly confined to the older writers. /Simjjlex and duplex obligatio were the old names for what are now more com monly called a single and a double or conditional bond. The party bound is still called the obligor, the party in whose favour the bond is made the obligee. The fourth like the third, is a use scarcely found except in the older writers. The word &quot; bond &quot; is of course a mere translation of obligatio. Obligations may be either perfect or im perfect. A perfect obligation is one which is directly enforceable by legal proceedings ; an imperfect or moral obligation (the naturalis obligatio of Roman law) is one in which the vinculum juris is in some respects incomplete, so that it cannot be directly enforced, though it is not entirely destitute of legal effect. A perfect obligation may become imperfect by lapse of time or other means, and, conversely, an imperfect obligation may under certain circumstances become perfect. Thus a debt may be barred by the Statute of Limitations and so cease to be enforceable. The obligation, however, remains, though imperfect, for if there be a subsequent acknowledgment by the debtor, the debt revives, and the imperfect obligation becomes again perfect. At one period there was some doubt among English lawyers whether a moral obligation could be regarded as sufficient consideration for a contract; it has now, however, been long decided that it cannot be so regarded. The Scotch law as to obligations closely follows the Roman. As in English law, the term obligation is used to express the instru ment itself by which the obligation is imposed. The bond or uni lateral obligation of Scotch law is a simple contract to pay the sum borrowed, &c., with interest. The English bond is generally a con tract to pay double the sum of the debt, with a condition that the bond is to be void if the debt be paid by a certain day. In Scotch law gratuitous obligations rank in competition with the claims of creditors ; in English law a voluntary bond, though effectual against the grantor, cannot be set up against creditors. Bonds in Scotland which are heritable securities still rank as immovables for certain purposes, though they have been made movables as regards the succession of the creditor, unless executors are expressly excluded (31 and 32 Viet. c. 101, s. 117). American law is in general agreement with English, except in the case of Louisiana, where the terms obligor and obligee are used in as wide a sense as the debitor and creditor of Roman law. By art. 3522 of the Louisiana civil code obligor or debtor means the person who has engaged to perform some obligation, obligee or creditor the person in favour of whom some obligation is contracted, whether such obligation be to pay money or to do or not to do something. The term obligation is important in America from its use in art. i. s. 10 of the constitution of the United States, &quot; Xo State shall pass any law. . . impairing the obligation of contracts. &quot; This does not affect the power of Congress to pass such a law. Con tracts between private individuals are of course within the provision. So are private conveyances, charters of private corporations, and statutory and other grants by a State. On the other hand, marriage and divorce, and arrangements which are political in their nature, such as charters of municipal corporations, licences to carry on particular trades, or regulations of poli&amp;lt;, are not within the pro vision. In order to fall within it, the law must act upon the terms of the agreement, and not merely upon the mode of pro cedure. If it act not upon the terms but upon the remedy, it im pairs the obligation if it purport to be retrospective, but it is valid so far as it applies to subsecpaent contracts. OBOE, or HAUTBOY. The oboe is an instrument con taining a conical column of air, which is set in vibration by means of a double-tongued reed. A series of holes pierced in the side of the pipe permits the instrumentalist to progressively shorten the column by the successive opening of the lateral holes, and thus produce a series of fundamental sounds, the scale of which, in the primitive instruments without keys, does not exceed the extent of an octave. All wind instruments with a conical column of air, whatever may be the mode by which that is set in motion, are subject to the laws of vibration of open pipes, according to which, by a stronger pressure in blowing, the oboe reproduces each of its fundamental sounds in the octave higher, and thus acquires a scale of two octaves, Avhich, partially chromatic in the old instruments, has be come completely chromatic by the adoption of keys. This extension of compass is further augmented in modern in struments, in the grave sounds by keys permitting lengthen ings of the primitive column of air, and in the acute by the employment of other partial sounds than the first of the harmonic series. In the present day the mean chro matic extent of the oboe is comprised between the notes =^H and M^ The double reed is the most simple, as it is probably the oldest, of all reed contrivances. It is sufficient to flatten the end of a wheat straw to constitute an apparatus cap able of setting in vibration by the breath the column of air contained in the rudimentary tube ; the invention of this reed is certainly due to chance. An apparatus for sonorous disturbance thus found, it was easy to improve it : for the wheat stalk a reed stalk was substituted, and in the extremity of its pipe another reed stalk much shorter in length was inserted, pared and flattened at the end ; and then came the lateral holes, probably another discovery of the great inventor chance. For the reed tube a wooden one was substituted, still preserving the reed tongue, and it is in this form, after having played an im portant part amongst the sonorous contrivances of antiquity, that we find the ancestor of the oboe playing a part no less important in the 16th century, in which it formed the interesting families of the cormornes, the corthols, and the cervelas. All these families have disappeared in the instru mental combinations of Europe, but they are still to be found in Eastern wind instruments, such as the Caucasian salamouri, the Chinese kwantze, and the hitshiriki of Japan. It is important to remark that the column of air in a cylin drical pipe, disturbed by any reed, submits to the laws of vibration of stopped pipes ; accordingly, to produce a sound of a given pitch, the pipe must be theoretically half as short as an open pipe would be to obtain a note of the same pitch. Moreover, open pipes under an increasing pressure of blowing, produce, in subdividing the air column, the harmonics according to the arithmetical progression 2, 3, 4, 5, &c., while the stopped pipes can only produce the odd harmonics in the series. In other words, the conical pipe reproduces its fundamental sounds in the interval of the octave, the cylindrical in that of the twelfth. A double reed associated with a cylindrical pipe can only be used for columns of air of small diameter. Practice has demonstrated that the reed stalk of which the tongue reed is made should not be of narrower internal diameter than the pipe containing the column of air it is to act upon. By the flattening necessary to form the tongues of a double reed, it must be tolerably large, from which it happens that its proper sound is relatively grave, and will only agree with instruments not above the region of the male voice. IH must be remembered that the reproduction of funda mental sounds in the twelfth is only possible by an artifice of modem invention. But it is evident that chance has again intervened to show that a very small double reed can set in vibration columns of air of considerable diameter, provided that the column becomes gradually narrower towards its superior extremity where it receives the reed, so as to terminate in a diameter equivalent to that of the reed itself. It is impossible to say when it was that man first employed the phenomena of double reeds and conical pipes, but the knowledge of them must at least have been later than that of the cylindrical pipe, which we may regard as directly furnished by nature. That antiquity made use of them, however, has been proved by M. Gevaert in his admirable Hiatoire de la imisique dans I antiquite ; but this learned author shows that the double-reed pipes held but XVII. 89