influence of Vibratory Motions. 439 
ing vibration tends to produce in order to form a nascent con- 
traction. If, therefore, as the note of the instrument deviates from 
the principal one, either below or above, the length of the nas- 
cent divisions which the vibrations tend to form becomes greater 
or less than that of the nascent division which the forces of figure 
tend, on their part, to produce ; and if an increasing conflict with 
the latter forces thence arises, on the other hand, below the prin- 
cipal note, the vibrations act more and more energetically in 
order to cause the new mode of transformation to prevail, and 
this increased action must compensate more or less for the in- 
creased conflict. ‘ 
We may here remark, that in the case of a note whose pitch 
is very low in comparison to that of the principal note, the new 
mode of transformation does not establish itself in the same 
manner as when the interval between the two notes is not great. 
In the latter case, indeed, in consequence of the small difference 
of length between the two kinds of nascent divisions, it is very 
probable that the action of the forces of figure becomes modified 
merely, and, as remarked in paragraph 15, lengthen or shorten 
their nascent divisions so as to make them coincide with those 
which correspond to the vibrations; but when the note of the 
instrument has a pitch so low that the length of the latter divi- 
sions considerably surpasses that of the others, when, for example, 
the note of the instrument is an octave below the note of the jet, 
and the vibrations are sufficiently intense to impose their mode 
of transformation upon the jet, we must admit that the action 
of the forces of figure is completely destroyed, so that there is no 
longer a modification of the first mode which adapts itself to the 
second, but an absolute substitution of the second for the first. 
§ 23. Experiment fully confirms what has been above said 
with respect to the variations of stability within, and in the 
neighbourhood of the limit, in a cylinder of liquid adhering to 
solid bases. A cylinder of oil was formed, and immersed hori- 
zoutally in an alcoholic mixture, after being placed between two 
discs* 31 millims. in diameter and 87 millims. apart; in this 
cylinder, therefore, the ratio of the length to the diameter was 
equal to 2°8, so that the figure was quite stable: this ratio, it 
will be seen, deviates from the limit still more than the one 
which, in the preceding paragraph, we found to belong to the 
nascent divisions of a jet of water, which, by the action of a so- 
norous instrument, is brought to yield a note a fifth above its 
principal one. In order to alter artificially the cylindrical form 
of the mass, the tip of the small syringe was slowly moved several 
times above the figure, each time starting from one of the discs 
_ * These discs were retained in position by a system similar to that repre- 
sented in fig. 27 of the Second Series, 
