610 



lETTER RESPECTING SOUND AND LIGHT. 



♦• proposed for his changeable harpsicliord, 

 " is neither in thatj nor in any other form, 

 " capable of practicable application." Pro- 

 fessor Robison, on the contrary, says, " We 

 " do not see how it can be disputed, that 

 ♦' Dr. Smith's theory of the beating of im- 

 " perfect consonances, is one of the most 

 " important discoveries both for the practice 

 ■" and the science of music, that have been 

 " oifered to the public. We are inclined to 

 " consider it as the most important that 

 " has been made since the days of Galileo. 

 " We are obliged to call it his discovery. 

 " Mersennus, indeed, had taken particular 

 " notice of this undulation of imperfect 

 " consonances, and had offered conjectures 

 " as to their causes ; conjectures not iinwor- 

 " thy of his great ingenuity. Mr. Sauveur 

 " also takes a still more particular notice of 

 " this phenomenon, and makes a most inge- 

 " iiious use of it for the solution of a very 

 ** important musical problem." P. Gj2 and 

 65 1. Why then are we obliged to call it Dr. 

 Smith's discovery, or indeed any discovery at 

 all ? Sauveur had already given directions for 

 tuning an organ pipe, by means of the rapid- 

 ity of its beating with others. Mem.de I'Ac. 

 1701. 475, ed. Amst. Dr. Smith ingeniously 

 enough extended the method : but it ap- 

 pears to me, that the e.vtension was perfectly 

 obvious, and wholly undeserving of the name 

 either of a discovery or of a theory. If Pro- 

 fessor llobison thinks otherwise, there is no- 

 thing further to be said ; but, in all proba- 

 bility. Dr. Smith considered this improve- 

 ment as constituting a very small part of the 

 merit of his treatise. No doubt an organ may 

 be more accurately tuned by counting the 

 beats, than by any other method, although 

 it may be questioned, whether the advantage 

 ©f counting the absolute frequency of the 



beats, will ever practically compensate the 

 tediousness of the process. 



It remains to be considered, whether Dr. 

 Smith's changeable harpsichord is, or is not, 

 an impracticable instrument; for, whatever 

 Signor Doria might exclaim, Dr. Smith 

 himself does not recommend his scale for 

 common use. It is the opinion of many un- 

 prejudiced practical persons, that all occa- 

 sional introduction of different semitones is 

 perfectly impracticable; and some, who have 

 heard the effect of Dr. Smith's instrument, 

 have declared, that to them it was by no 

 means agreeable. And indeed, if we pay 

 sufficient attention to the passages and mo- 

 dulations of the greatest composers, we shall 

 be convinced, that, granting all possible dex- 

 terity in the performer, it would be abso- 

 lutely impracticable to adapt them to an in- 

 strument, so different from that for which they 

 were composed, as Dr. Smith's is from the 

 common harpsichord. It may easily be con- 

 ceived, that an organ, very correctly tuned, 

 as Mr. Watt's probably was, for a particu- 

 lar key, might appear " sopra modo bellis- 

 simo" in that key; but the sequel of the 

 story shows literally what Dr. Smith has al- 

 lowed, that his temperament is inapplicable 

 to our instruments, since it was utterly im- 

 possible to sing with it in the' key of Ees, or 

 E flat, a key of exceedingly frequent occur- 

 rence. I have been informed, on the best 

 authority, that Dr. Smith restricted the or- 

 ganist of Trinity College to such keys and 

 modulations, as were best suited to the sys- 

 tem by which the organ was tuned; and that 

 organ, as well as the instruments which 

 w-ere made for Dr. Smiili, has long been 

 tuned according to the more common me- 

 thod. 



I spoke of Dr. Smith's system with flat- 



