222 On the TroduBkn of artificial Cold. 



determines the pitcb, the found is confiderably weakened, and its pitch is raifed. Fig. lo, 

 reprefents the fe£lion of the inftrumcnt with which I made the experiment. It confifts of 

 two pipes A and B. A fquare pipe was conftrudled of metal, with an aperture in one fide 

 like thofe pipes of an organ in the flute flop. When its end was open its lowed found was 

 in unifon with G above the fifth line of the treble flave. 



A thin piece of metal was now turned over three fides of the piece of wood upon which 

 the pipe A had been turned, and its edges were foldered to two corners of that pipe. Two 

 tubes being thus conftrufled, the aperture for producing the found was in the partition 

 between them. When that end of the tube B which is neareft the fide aperture was clofed, 

 and the inftrument was blown, its tone was confiderably changed, and a full note higher. 



An inftrument of this kind may be ufed when any of the gafes are employed in the pro- 

 du£tion of found. 



The harmonical founds of this pipe are A, oftave to its loweft found ; E, twelfth ; A 

 double oftave or fifteenth ; and C (harp, feventeenth major. I confider the change in its 

 original tone and pitch to be owing to the diminution of preiTure upon the (;de aperture. 

 Flame produces nearly fimilar efFefts. Bring the flame of a candle very near the fide aper- 

 ture of a fmall organ pipe, and its found will rife confiderably. 



I think a mufical inftrument might be formed upon a plan nearly fimilar to that of Fig. 

 10. After the proper length of the pipes A and B is determined, fix holes may be made 

 into each, fo near the partition, that all the twelve may be clofed by fix fingers. 



Our fmall wind inftruments have many imperfe£lions, but are the objefks of fo little 

 jdire£l importance to fociety, that we do not expeft much celerity in their improvement. 



I am, SIR, 



Your humble Servant, 



WILLIAM CLOSE. 

 Daltofi, July 24, l^ol. 



IV. 



On the ProduBion of artificial Cold by Means of Muriate of Lime. By Mr. RiCHARD 

 Walker. (Philof Tranf. idoi.J 



HE fubjeft of the means of producing artificial cold, or the conftitution of frigorific- 

 mixtures, I had confidered as exhaufted, in the Papers I have already had the honour to 

 lay before this Society: fo far as relates to that part of the fubjedl; which confifts in gene- 

 rating artificial cold without the ufe of ice, it ftill remains fo with mc, having nothing new 

 to offer. 



A con- 



