ation: 7

[Tau] = .0128 sec.]

[Illustration: 8

[Tau] = .0149 sec.]

[Illustration: 9

[Tau] = .0149 sec.]

SERIES XIV.

_Engravings of Instantaneous Photographs of the Splash of a Drop of
Water falling 40 cm. into Milk._

Scale about 6/10 of actual size.

[Illustration: 1]

[Illustration: 2]

[Illustration: 3]

[Illustration: 4

[Tau] = 0 sec.]

[Illustration: 5]

[Illustration: 6

[Tau] = .0056 sec.]

[Illustration: 7

[Tau] = .0163 sec.]

[Illustration: 8]

[Illustration: 9

[Tau] = .0182 sec.]

[Illustration: 10

[Tau] = .0197 sec.]

[Illustration: 11

[Tau] = .0262 sec.]

[Illustration: 12

[Tau] = .0391 sec.]

[Illustration: 13

[Tau] = .0514 sec.]

[Illustration: 14

[Tau] = .0601 sec.]

[Illustration: 15]

[Illustration: 16

[Tau] = .080 sec.]

[Illustration: 17]

[Illustration: 18

[Tau] = .101 sec.]

With respect to these photographs,[6] the credit of which I hope you
will attribute firstly to the inventors of the sensitive plates, and
secondly to the skill and experience of Mr. Cole, I desire to add that
they are, as far as we know, the first really detailed objective views
that have been obtained with anything approaching so short an exposure.

Even Mr. Boys' wonderful photographs of flying bullets were after all
but shadow-photographs, and did not so strikingly illustrate the
extreme sensitiveness of the plates, and I want you to distinguish
between such and what (to borrow Mr. F.J. Smith's phrase) I call an
"objective view."

It remains only to speak of the greater irregularity in the arms and
rays as shown by the photographs. The point is a curious and interesting
one. In the first place I have to confess that in looking over my
original drawings I find records of many irregular or unsymmetrical
figures, yet in compiling the history it has been inevitable that these
should be rejected, if only because identical irregularities never
recur. Thus the mind of the observer is filled with an ideal splash--an
"Auto-Splash"--whose perfection may never be actually realized.

But in the second place, when the splash is nearly regular it is very
difficult to detect irregularity. This is easily proved by projecting
on the screen with instantaneous illumination such a photograph as that
of Series X., Fig. 6. My experience is that most persons pronounce what
they have seen to be a regular and symmetrical star-shaped figure, and
they are surprised when