sou 



conCderably below the pitch of either of the bodies whofe 

 vibrations it accompanies, and which confequently cannot 

 immediately proceed from either of thefe bodies. To take 

 the firlt of the above-mentioned intervals, that of the greater 

 third, for an example : a third found is here heard, fuch as 

 would be produced by the aftual vibration of a firing of the 

 fame diameter and tenfion with, but of double the length of, 

 that which produced the loweft note of the interval. As no 

 fuch Itrmg, however, is employed in the experiment, we are 

 obliged to feek for the caufe of this new found in the air, or 

 other medium of found, or in the organ of hearing, or in 

 fome internal modification of the fenfitive faculty. 



As the immenfe variety of our fenfations of colour is juilly 

 fuppofed to be produced by an equal diverfity of coloured 

 particles of light, each highly qualified to excite one par- 

 ticular fenfation and no other, fo fome, with M. Mairan, 

 have fuppofed, that our numerous and diverfified fenfations 

 of mufical tones are not produced by the undulations of the 

 air, confidered in its whole mafs, but by aerial particles, 

 fpecifically different in elafticity, magnitude, figure, &c. 

 each capable of exciting, by its motions or other modifica- 

 tions, the idea of only one determinate tone. Therefore we 

 might fay, that the two orders of particles which give the 

 tones C and :, either by an harmonical congruity in their 

 fpring with that fet of particles which give the third found 

 C below, or by fome other peculiar affinity to them, are 

 qualified, by their joint aftion on thefe laft-mentioned par- 

 ticles, to give them that particular modification, by which 

 they excite in us the fenfation of that fpecific tone to which 

 they are adapted. Or, may we not conceive in general, that 

 a mixture of two given tones may excite the idea of a third 

 and different found, in fome fuch manner as two given co- 

 lours, e. g. blue and yellow ; nay, the paft impreHions of 

 thefe colours excite the idea of green, different from both 

 of them. 



But if the effeft is produced merely by the organ of hear- 

 ing, we may obferve, that, from a confideration of the fpiral 

 and conical Itrufture of the cochlea, fome phyfiologifts have 

 been tempted to imagine, that the branches or filaments of 

 the auditory nerve, after puffing out from the nucleus or 

 axis of the cochlea, are llrained upon the fpiral plates, like 

 the radii of a circle, and become gradually fliorter and 

 fijorter toward its apex. It may be fuppofed likewife, that 

 of thefe nervous firings, the longefl, which are in the bafis 

 of the cochlea, are adapted to receive the tremors or other 

 impreffions, and convey to the mind the ideas, of grave 

 tones ; and the fhorter nervous chords, fixed more towards 

 the apex of the cone, thofe of acute founds. This being 

 allowed, and taking the former interval C e for an example, 

 it may be faid that the tone C, befides afting on the nervous 

 chord appropriated to excite the idea of that tone, muft aft 

 likewife on another nervous chord of double its length, fitu- 

 ated towards the bafis of the cochlea, &c. and which is na- 

 turally adapted to receive and tranfmit to the mind C, the 

 oftave below ; but which the upper tone C now divides into 

 two equal parts, each giving tones unifon to the faid note C. 

 The tone :, \\\ like manner, will excite five equal vibrations 

 in each of the halves of this nervous chord ; all which, like- 

 wife, produce fenfations unifon with itfelf. Thefe pheno- 

 mena at leaft are invariably obferved to be produced in mu- 

 fical firings. Thus we obtain the unifons to C and e : and 

 farther, the laft-mentioned chord thus vibrating in two and 

 in tea parts, and from one extremity of it to the other, mav 

 fairly be fuppofed to vibrate in its whole length ; in which 

 cafe it muft excite in the mind the idea of its own funda- 

 mental tone, the third found C, an oftave below the firft of 

 thefe notes, and a tenth below the latter. See, on the fub- 



SOU 



jeft of this article, Encyclop^die, art. Bafe F<»n>AMlW- 

 TALE. Principles and Power of Harmony, 4to. 1771, and 

 Monthly Rev. vol. xlv. p. 371, &c. 



Sound, in Geography, denotes a ftrait or inlet of the 

 fea, between two capes or head-lands. 



The Sound is ufed, by way of eminence, for that famous 

 flrait which joins the German fea to the Baltic. 



It is fituate between the ifland of Zealand and the coaH 

 of Schonen. It is about fixteen leagues long, and in gene- 

 ral five broad, excepting againil the caftle of Cronenburg, 

 (which fee,) where It is but one ; fo that there is there no 

 paflage for veflels but under the cannon of the fortrefs. 



This was firft erefted for the better commanding of the 

 Sound, as was alfo Helfinburgh, on the oppofite fhore in 

 Schonen, for the protection of fhips from pirates, then nu- 

 merous in that fea. 



This has given occafion to the Danes to fettle a toll on 

 all veffeU, which is faid to be one of the beft revenues of 

 the crown of Denmark ; and to forbid all pilots from pall- 

 ing through the Great and Little Belt, which are two other 

 inlets into the Baltic, though fomewhat lefs commodious 

 than the former. 



All nations who traffic into this part of the North are 

 fubjeft to this toll : the Swedes, indeed, were exempted 

 from it by the treaty of 1644, but by the treaty of 1720, 

 they are excluded the privilege, and put on the fame foot- 

 ing with their neighbours. 



By the treaty of Spire, made between the Danes and 

 Charles V. in behalf of his Netherland fubjefts, the toll for 

 this pallage was fixed at two rofe nobles for a fhip of two 

 hundred tons ; yet, in the year 1640, the fame was raifed to 

 upwards of five hundred rix-dollars. 



The connivance of our king James I. who had married a 

 daughter of Denmark, and the wars which the Hollanders 

 had been long engaged in for their liberty, furnifhed the 

 occanon for fo grievous an exaftion. Of late years, the toll 

 has been again reduced to an eafier footing. 



Cromwell was bent on extorting this pafFage from the 

 Danes, and had probably effefted it, but that, before the 

 fleet for that purpofe arrived there, he died. 



However, in 1659, England, Holland, and France, by 

 treaty, obliged Denmark to ftipulate, that it fhall never be 

 increafed upon the faid three nations, who are mutual 

 guarantees to this treaty. 



The origin and progreis of this impofition (which, from 

 an eafy contribution, of which we have an account fo early 

 as 1348, voluntarily' paid by merchants for maintaining 

 lights on certain places of the coaft, and for protedlion of 

 fhips from pirates, and of which the king of Denmark was 

 only treafurer or truftee, grew at length to be a heavy bur- 

 den on trade, as well as a kind of fervile acknowledgment 

 of his fovereignty of thefe feas) is given in lord Molefworth's 

 Account of Denmark, chap. iii. p. 1 1. feq. 



As to the prefent ftate of this toll, Dr. Bufching, in his 

 New Geography, obferves, that it is on an equal footing 

 with all nations, excepting the Hamburghers, who pay more 

 than others : the Enghfh, Dutch, Sivedifh, and French 

 fhips, are not fearched when provided with proper pafies, 

 according to treaties ; and pay down only i pir cent, for 

 fuch goods as are not fpecified in the tarif. But all other 

 nations pay l\ per cent, and muft fubrait to be fearched. 

 With regard to the Hanie Towns, on the Baltic, there is 

 a greai variety in the toll they pay, for almoft every one of 

 thofe towns is treated with in particular. See Denmark 

 and Elsineur. 



On the Sound, accounts are kept in rix-dollars, of 4orts, 

 ■which contain 96 fkillings Danifh, or 48 (hillings Ham- 

 burgh 



