into a duration too narrow to permit of the separation of its moments.
We must insist on this last point, to which we have already alluded elsewhere, and which weThere may be as many tensions of duration as there are degrees of consciousness. regard as essential. The duration lived by our consciousness is a duration with its own determined rhythm, a duration very different from the time of the physicist, which can store up, in a given interval, as great a number of phenomena as we please. In the space of a second, red light,—the light which has the longest wave-length, and of which, consequently, the vibrations are the least frequent—accomplishes 400 billions of successive vibrations. If we would form some idea of this number, we should have to separate the vibrations sufficiently to allow our consciousness to count them, or at least to record explicitly their succession; and we should then have to enquire how many days or months or years this succession would occupy. Now the smallest interval of empty time which we can detect equals, according to Exner, 1500 of a second; and it is even doubtful whether we can perceive in succession several intervals as short as this. Let us admit, however, that we can go on doing so indefinitely. Let us imagine, in a word, a consciousness which should watch the succession of 400 billions of vibrations, each instantaneous, and each separated from the next only by the 1500 of a second necessary to distinguish them.
