LETTER RESPECTING SOUND AND LIGHT. 



.009 



specting the theory of colours, will throw 

 new light on all the most interesting piutsof 

 optics, while, by a comparison with the obvi- 

 ous inferences from Dr. Herschel's important 

 discoveries, they will also lead to some ma- 

 terial illustrations of the phenomena of heat. 



I shall now trouble you with some remarks 

 in reply to Professor Robison : the passage 

 to which I allude is this : 



" We are surprised to see this work of Dr. 

 Stnitlf greatly undervalued, by a most inge- 

 nious gentleman, in the Philosophical Trans- 

 actions for 1800, and called a large and ob- 

 scure volume, which leaves the matter just as 

 it was, and its results useless and impracti- 

 cable. We are sorry to see this : because we 

 have great expectations from the future la- 

 bours of this gentleman in the field of harmo- 

 nics, and his late work is rich in refined and 

 valuable matter. We presume humbly to re- 

 commend to him, attention to his own ad- 

 monitions to a very young and ingenious 

 gentleman, who, he thinks, proceeded too 

 far in animadverting on the writings of New- 

 ton, Barrow, and other eminent mathemati- 

 cians." Encyclop. Brit. Suppl. Art. Tempe- 

 rament, p.(i52. 



According therefore to the author of this 

 article, I have in the first place taken the li- 

 berty of giving severe advice, to a young 

 mathematician wlio had never asked it ; se- 

 condly, this advice is equally applicable to 

 my own presumption ; and thirdly. Dr. 

 Smith's treatise on harmonics is a work in- 

 titled to the highest praise. 



1 did, in fact, endeavour to show, that the 

 gentleman in question had overlooked the 

 labours of some former authors relative to 

 his subject, but I accompanied my remarks 

 witli nothing iike admonition. I have read 

 Dr. Smith's work with attention, and I 



VOL. II. 



imagine, from the polite manner in which 

 Professor Robison is pleased to speak of mj' 

 essay, he will not hesitate to allow, that I 

 have understood it. I took it up with great 

 expectations; those expectations having been 

 completely disappointed, I thought it right to 

 state my cool and unprejudiced opinion of 

 its merits, in order to prevent a similar dis- 

 appointment in others. It is impossible,* 

 therefore, that an " attention" to any " ad- 

 monitions" of a general nature, wherever they 

 may be found, can influence such an opi- 

 nion ; and so far only as I am supposed to be 

 an incompetent judge on the subject of har- 

 monics, can it be asserted, that it W9,s either 

 biameable or superfluous for me to express 

 that opinion. As a mathematician, and an 

 optician, I value Dr. Smith highly, but I 

 must still beg leave to affirm, that his whole 

 book of harmonics contains far, far less in- 

 formation, than either of the articles Tem- 

 perament and Trumpet, in the Supplement of 

 the Encyclopaedia. 



I do no\ mean to be understood, that this 

 work is so contemptible, as not to contain 

 the least particle of important matter ; but 

 it appears to me, that its errors counterba- 

 lance its merits. The only improvement on 

 which Professor Robison himself "seems to 

 .set a high value, is the application of the 

 phenomena of beats to tuning an instrument : 

 on the other hand, 1 conceive tliat the mis- 

 statement, relative to the noninterierence of 

 different sounds, is an inaccuracy which far 

 outweighs the merit of Dr. Smith's share of 

 that improvement. I have asserted, that Dr. 

 Smith has written a large and obscure vo- 

 lume, which, for every " purpose, but for the 

 " use of an impracticable instrument, leaves 

 " the whole subject of temperament precisely 

 " where it found it ;" and that " the system, 

 4 I 



