288 Intelligence and Miscellaneous Articles. 



figtiratrices"). If the physical fact is admitted — and it seems to be 

 indisputable — that a liquid cylinder attains a limit of stability when 

 the proportion between its length and its diameter is in the ratio of 

 22 to 7, it is almost a physical necessity that the jet should assume 

 the constitution indicated by the observations of Savart. It like- 

 wise seems highly probable that a liquid jet, while in a transition 

 stage to discontinuous drops, should be exceedingly sensitive to the 

 influence of all kinds of vibrations. It must be confessed, however, 

 that Plateau's beautiful and coherent theory does not appear to em- 

 brace Savart's last experiment, in which the musical tones were pro- 

 duced by a jet of water issuing under the surface of the same liquid. 

 It is rather difficult to imagine what agency the "forces of figure" 

 could have, under such circumstances, in the production of the phtC- 

 nomenon. This curious experiment tends to corroborate Savart's ori- 

 ginal idea, that the vibrations which produce the sounds must take 

 place in the glass reservoir itself, and that the cause must he inhe- 

 rent in the phrenomenon of the flow. 



To apply the principles of Plateau's theory to gaseous jets, "we 

 are compelled to abandon the idea of the non-existence of molecular 

 cohesion in gases. But is there not abundant evidence to show that 

 cohesion does exist among the particles of gaseous masses ? Does 

 not the deviation from rigorous accuracy, both in the law of Mariotte 

 and of Gay-Lussac, — especially in the case of condensable gases, as 

 shown by the admirable experiments of M. Ilegnault, — clearly prove 

 that the hypothesis of the non-existence of cohesion in aeriform bodies 

 is fallacious ? Do not the expanding rings which ascend when a bub- 

 ble of phosphuretted hydrogen takes fire in the air, indicate the ex- 

 istence of some cohesive force in the gaseous product of combustion 

 (aqueous vapour), whose outlines are marked by the opake phos- 

 phoric acid ? In short, does not the very form of the flame of a 

 "fish-tail" burner demonstrate that cohesion myst exist among the 

 particles of the issuing gas ? It is well known, that in this burner 

 the single jet which issues is formed by the union of two oblique Jets 

 immediately before the gas is emitted. The result is a perpendicular 

 sheet of flame. How is such a result produced by the mutual action of 

 two jets, unless the force of cohesion is brought into play ? Is it not 

 » obvious that such a fan-like flame must be produced by the same 

 causes as those varied and beautiful forms of aqueous sheets deve- 

 loped by the mutual action of jets of water, so strikingly exhibited 

 in the experiments of Savart and of Magnus ? 



If it be granted that gases possess molecular cohesion, it seems 

 to be physically certain that jets of gas must be subject to the same 

 laws as those of liquid. Vibratory movements excited in the neigh- 

 bourhood, ought therefore to produce modifications in them ana- 

 logous to those recorded by M. Savart in relation to jets of water. 

 Flame or incandescent gas presents gaseous matter in a visible form 

 admirably adapted for experimental investigation; and ivhen produced 

 by a jet, should be amenable to the principles of Phiteau's theory. 

 According to this view, the pulsations or beats which I observed in 

 the gas-flame when under the influence of musical sounds, are pro- 

 duced by the conflict between the aerial vibrations and the " forces 



