328 
MR. FARADAY ON THE FORMS AND STATES 
94. The beautiful appearance exhibited when the crispations are produced 
in sunshine, or examined by a strong concentrated artificial light, has been 
already referred to (78. 7 9)- When the reflected image from any one heap is 
examined, (for which purpose ink (75) or mercury (77) is very convenient,) it 
will be found not to be stationary, as would happen if the heap was permanent 
and at rest, nor yet to form a vertical line, as would occur if the heap were 
permanent but travelled to and fro with the vibrating plate ; but it moves so 
as to re-enter upon its course, forming an endless figure, like those produced 
by Dr. Young’s piano-forte wires, or Wheatstone’s kaleidophone, varying with 
the position of the light and the observer, but constant for any particular posi- 
tion and velocity of vibration. Upon placing the light and the eye in posi- 
tions nearly perpendicular to the general surface of the fluid, so as to avoid 
the direct influence of the motion of vibration, still the luminous, linear, endless 
figure was produced, extending more or less in different directions, according 
to the relation of the light and eye to the crispated surface, and occasionally 
corresponding in its extent one way to the width of the heap, i. e. to the di- 
stance between the summit of one heap and its neighbours, but never exceeding 
it. The figure produced by one heap was accurately repeated by all the heaps 
when the vibrating force of the plate was equal ( 70 ) and the arrangement 
regular. 
95. The view which I had been led to anticipate of the nature of the heaps, 
from the effects described in the former paper, were, that each heap was a per- 
manent elevation, like the cones of lycopodium powder (53. 58), the fluid rising 
at the centre, but descending down the inclined sides, the whole system being 
influenced, regulated, and connected by the cohesive force of the fluid. But 
these characters of the reflected image, with others of the effects already de- 
scribed, led to the conclusion, that notwithstanding the apparent permanency 
of the crispated surface, especially when produced on a small scale, as by the 
usual method, the heaps were not constant, but were raised and destroyed with 
each vibration of the plate ; and also that the heaps did not all 
exist at once, but (referring to locality) formed two sets of equal 
number and arrangement, fig. 23, never existing together, but 
alternating with, and being resolved into each other, and by their 
rapidity of recurrence giving the appearance of simultaneous and 
Fig. 23. 
