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33. Sir David Solomon’s Experiment in 1894. Proc. Royal So., June 21, ’94. Nature, Lon. Sept. 13, ’94, p. 490.—With a tube having a perforated diaphragm, he noticed a “forcing effect” at and near the hole. The striae had the appearance of being pushed through from the longer part of the tube—the diaphragm not being in the centre. There was no passage way around the diaphragm—only through the small puncture. ssss1.

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34. Riess’s Experiment. Electric Images. Riess’s Reibungs. vol. 2, § 739.—He laid a coin upon a plate of glass and charged the same electrically about one-half of an hour or more. Upon removing the coin and sprinkling the plate with dust, an engraving of the coin was visible upon the glass. ssss1. A suitable dust is licopodium powder.

35. Sanford and McKay’s Experiment. Electrographs. Original Contribution by Prof. McKay of Packer Inst., Brooklyn, May, ’96.—The picture of the coins in Fig. IX, was produced by the apparatus shown in Fig. VIII, t, t, tinfoil, p, photographic plate with coins on sensitive side, all wrapped in black paper. Fig. VIII represents the general arrangement for taking electrographs. This particular one was made by removing the upper tinfoil and touching each coin successively with wire from one of the poles, while the other wire was connected with tinfoil on the opposite side. The condenser thus formed is charged and discharged many times by a Holtz machine or induction coil. This is not a new discovery, it was first described by Prof. Sanford, I think, of Leland Stanford University, two or three years ago. Other claimants of earlier date probably exist.