CON 



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CON 



CONSECUTIVE Chords, in Music, imply a succes- 

 sion or repetition of the same consonance in similar 

 motion. Dr Holder has shewn, that this succession of 

 the same chord, in musical passages, where the parts 

 move the same way, either up or down, and not occa- 

 sioned by the different parts of the composition moving 

 different ways, or one up and the other down, is cloy- 

 ing and disagreeable, and therefore forbidden in con- 

 cords, by the rules of harmony or counterpoint, and 

 that consecutive discords are not less offensive, so that 

 the rule against consecutive intervals is in reality gene- 

 ral ; and he remarks, that the many writers on compo- 

 sition who have hmited their prohibition to consecutive 

 fifths, octaves, unisons, and fourths, have not duly con- 

 sidered, that it is only the mingling of major and minor 

 thirds, sixths, &c. in the scale, that allows any of these 

 to be used consecutively, any more than the perfect 

 concords, as they improperly call them, as above-men- 

 tioned ; and, that consecutive major thirds, or minor 

 thirds, &c. without the mixture of the two, would as 

 strikingly offend, as those against which the prohibi- 

 tion has hitherto been most levelled. When, instead 

 of an immediate succession of the same chord, an alter- 

 nate, or any other similar succession of the same chords 

 in the scale, occur in ascending or descending diatoni- 

 cally, — the same is called a sequence, (g) 



CONSONANCE, in Music, is a term for the union 

 or blending of two sounds, produced at the same time, 

 and includes every possible musical interval. 



Consonances naturally divide themselves into three 

 important classes, viz. 1st, Perfect Concords, (see that 

 article,) or such as produce an agreeable and pleasing 

 effect on the ear. 2d, Imperfect, or tempered, Con- 

 cords, which never can differ much from some one of 

 the perfect concords, and have rather a pleasing effect, 

 each distinguished by the peculiar characters of the per- 

 fect concord to which it belongs, but alloyed or disfi- 

 gured by an accompanying and disagreeable phenome- 

 non, called Beats, which are sorts of rva, ma, ya, ya, 

 &c. noises, (see that article,) increasing in quickness, 

 as the tempered concord is more and more imperfect, 

 either in excess or defect, until at length these separate 

 and distinct noises, becoming too quick to be separately 

 distinguished, they blend into a faint discordant note, 

 (whenever the beats exceed about 12^ in a second of 

 time,) which again blends with, or forms a consonance, 

 in a certain degree, with the imperfect concord itself; 

 and where the imperfection is a little farther increased, 

 the same degenerates into a most disagreeable flutter 

 ard dissonance, as the experiment that we shall pre- 

 sently describe, from the late Dr Robison, will shew, 

 if carefully repeated. And, 3d, Discords, or intervals, 

 that have a grating or disagreeable jarring effect on the 

 ear, or a fluttering roughness in some cases, as will fur- 

 ther appear below. 



The difficulties under which the science of harmonics 

 still labours, for want of any general and characteristic 

 distinction of consonances, into concords and discords, 

 has been pretty fully shewn in the former of these ar- 

 ticles ; and we cannot but recommend a careful repeti- 

 tion of Dr Robison's experiment below, with still more 

 perfect and delicately contrived apparatus, as the most 

 likely means, from the contemplation of the effects of 

 all the possible consonances that thence arise, of lead- 

 ing to an extension of our knowledge of the character- 

 istic properties of each of the above three classes of con- 

 sonances. 



Dr Robison's experiment, alluded to above, i6 to be 

 vol. vii. part r. 



thus conducted, on a Sonometer, provided with two' 

 strings, and a resined wheel, that can be steadily turn- - 

 ed by the foot, or by an assistant, for the purpose 

 of causing both these strings to sound, clearly and 

 smoothly, for any length of time ; the moveable bridge 

 to one of these strings should slide with great truth and 

 steadiness, by means of a screw or a rack and pinion, 

 and not strain or force the string out of its position, or 

 sensibly alter its tension in any part. These two strings, 

 being of the same wire and length, when the sliding 

 bridge is nearly, but not quite, drawn back, are to be 

 tuned, by turning their pegs to a perfect unison. Then, 

 Jirst, in order to try the effect of flattening this unison, 

 draw the moveable bridge a little further back, and the 

 smooth uniform consonance of the two strings will be 

 at first accompanied by slow beats ; these, by a little 

 further withdrawing of the bridge, or lengthening of the 

 string, will increase in quickness and disagreeable ef- 

 fect, until, by a further and farther withdrawing of the 

 bridge, they will become too quick to be distinctly 

 counted ; shortly after which, they will seem to form a 

 new very deep, though not very loud, sound, varying 

 in its pitch, and becoming more acute as the bridge is 

 farther drawn back ; and a rattling flutter, the com- 

 bined effect of this new sound and the two strings, will 

 succeed ; and after that a disagreeable jar. 



The bridge may now be returned to its first position, 

 or where a smooth uni-consonance (I) is heard, with- 

 out any beats that are sensible, however slow ; then, 

 the moveable bridge being slowly and gradually mo- 

 ved forwards, at first a slow and by degrees a quicker 

 beating, (like those before described, but beating sharp, 

 or increasing the contrary way,) will be heard, and in- 

 crease in rapidity, as the bridge is advanced, until they 

 can no longer be counted ; and at length these will de- 

 generate into a violent rattling flutter, which will soon 

 after, as the bridge advances, become a disagreeable 

 jarring noise. Still advancing the bridge, vile discor- 

 dant noises will result from the sound of the two 

 strings, until the variable string has been shortened al- 

 most ^th of the length of the fixed string, or where a 

 little more than i^ths of the string continues to sound; 

 when a very rapid angry flutter will commence, and 

 which will become rather less rapid and offensive to the 

 ear, as the point T%ths is approached (IV), and the same 

 will then increase, as the bridge advances, until the dis- 

 cordant jar again prevails, and which will continue un- 

 til £ths of the string is approached, when a nearly simi- 

 lar flutter will commence and decrease, and again in- 

 crease as this point (II) is passed by the bridge ; the 

 jar beginning again and accompanying the motion of 

 the bridge, until arrived within some distance of |ths of 

 the fixed string's length, when a flutter and rapid beats 

 will succeed, decreasing in frequency, until at £ths, or 

 when the minor third (3rd) is sounded, they will cease 

 entirely, and a concord will result, rather agreeable than 

 otherwise, but strongly marked by a mournful melan- 

 choly hi the expression. 



This last concord being sufficiently noticed, the 

 bridge is again to be advanced by slow degrees, and the 

 beatings will commence again, and increase in quick- 

 ness, and at length flutter ; and the same grating dis- 

 sonance as before will succeed : this will continue until 

 near the point marked £ths, when the flutter and beat- 

 ings will again commence, having a peevish fretful ex- 

 pression as they decrease, owing to the advance of the 

 bridge, to the exact point marking the major third(III) ; 

 when all beating having ceased, the peculiarly enliven- 

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