As to the "non-striking vacuum," the point to be noted is that it can occur only with low frequency impulses, and it is necessitated by the impossibility of carrying off enough energy with such impulses in high vacuum since the few atoms which are around the terminal upon coming in contact with the same are repelled and kept at a distance for a comparatively long period of time, and not enough work can be performed to render the effect perceptible to the eye.

In elucidation of the preceding remark it is necessary to state that what is a "non-striking" vacuum for a coil operated, as ordinarily, by impulses, or currents, of low-frequency, is not, by far, so when the coil is operated by currents of very high frequency.

The shadow of the upper edge of the tube is then sharply defined upon the bulb. At a somewhat lower degree of exhaustion, which is about the ordinary "non-striking" vacuum, and generally as long as the matter moves predominantly in straight lines, the screen still does well.

As long as ordinary coils, even very large ones, were used, the study of the subject was limited, because just at a point when it became most interesting it had to be interrupted on account of the "non-striking" vacuum being reached.

If the whites, in turn, opened the doors of economic opportunity to the ex-slave instead of importing more European immigrants, Washington said that the nation would have an English-speaking non-striking labor force. Gradually, individual Afro-Americans would gain trust, acceptance, and respect. The class line based on color would be replaced by one based on intelligence and morality.

There are two more features upon which I think it necessary to dwell in connection with these experiments the "radiant state" and the "non-striking vacuum." Any one who has studied Crookes' work must have received the impression that the "radiant state" is a property of the gas inseparably connected with an extremely high degree of exhaustion.