Exp4rlme{its and Iv^ulries yefpe£}ingSfiUitd and Light., up 



Figs. 7—12. A fimilar fe£lion, where the tube was.i in diameter, compared with the 

 fedtion as, inferred from the experiments with t«ro gages, which is reprefeiited bf a dotted 

 line. From this comparifon it appears, that where the velocity of th,c current was fraall, 

 its central parts only difplaced the liquid ; and that, where it was great, it difplaced, on 

 meeting with rcfiftance, a furf^ce fomewhat greater than its own fecibn. The preflure 

 was in Fig. 7, I, Fig, 8,. 2. Fig. 9, 3. p'ig, 10, 4^ Fig. it, 7. tig.'.ii^ lO. 



Figs. 13—20. A, the half feflion.oi a.ftream of air from a tube .1 in diameter, as 

 inferred from experiments with two water gages. The prelTure was in Fig. 13, .1. Fig. 

 14, .2. Fig. 15, .5. Fig. 16, I. Fig. 17, 3. Fig. 18, 5. Fig. 19, 7. Fig. 20, 10. 

 The fine lines, marked B, (how, the refult o£ the obfervations with an aperture .15 in 

 diameter oppofed to the ftream ; C with .3 ; and D with .5. 



Figs. 21 — 23. A, the half fe£lion of a current from a tube .3 in diameter, with a 

 preflure of .5, of i, and of 3. B fliows the courfe of a portion next the axis of the cur- 

 rent, equal in diameter to thofe reprefented by the laft figures. 



Fig. 24. The appearance of a ftream of fmoke, forced very gently from a fine tube. 

 Fig. 25 and 26, the fame appearance when the prelTure is gradually increafed. 



Fig. 27. SeeSeaionlll. 



Fig. 28. The perpendicular lines over each divifion of the horizontal line fliow, by their 

 length and diftance from that line, the extent of piefiure capable of producing, from the 

 refpeftive pipes, the harmonic notes indicated by the figures oppofite the beginning of 

 each, according to the fcale of 22 inches parallel to them. The larger numbers, oppofite 

 the middle of each of thefe lines, fliow the number of vibrations of the correfpondlng 

 found In a fecond. 



Figs. 29 — 33. See Section X. * 



Fig. 34. The combination of two equal founds conftituting the interval of an o«9;ave, 

 fuppofing the progrefs. and regrefs of the particles of air equable. Figs. 35, 36, 37, a 

 fimilar reprefentatlon of a major third, major tone, and minor fixth. 



Fig. 38. A fourth, tempered about two commas. 



Fig. 39. A vibration of a fitnilar nature, combined with fubordinate vibrations of the 

 fame kind in the ratios of 3, , 5, and 7* 



Fig. 40. A vibration reprefented by a curve of which the ordlnates are the fines of 

 circular arcs Increafing uniformly, correfpondlng with the motion of a cycloidal penduloni, 

 combined with fimilar fubordinate vibrations in the ratios of 3^, 51 aad 7> 



* By fome overfight thcilguref 29.t;p 40 inclt^ive are nat i^fert^d ut'ftexngrayings. They fliall appeu 

 in our next.— N. _'" " " " ' ■" . 



Vo*. v.— JwLY 1801, S Plate 



