The shock of the above-mentioned tubes was sensibly greater when received through this last wire than when received simply, but was considerably less than when received through the first wire.

They were then compared by sound with the same tube charged to 5, when the sound of the shock passed through the new wire was sharper, and the other fuller.

The sound of the shock passed through the new wire seemed full as brisk, and the light as white as of that passed through 55 of sat. sol., but not near so strong as when the wires in sat. sol. were in contact, the sound and light, however, seemed nearly of the same kind. When distance in tube was 1.1 the sound was evidently less loud than that with the wire.

When the shock was allowed to pass through both wires, the sound, I thought, seemed much of the same kind as when passed through new wire singly.

The shock passed through both wires felt plainly greater than the simple shock, and the difference seemed greater than that between the new wire simply and the simple shock.

In the foregoing the shock passed at the same time through both wires, but it was then tried so that it should first pass through old and from thence through new wire.

The shock felt then evidently stronger than the simple shock or that through new wire alone, but I could not tell whether it was greater or less than that through the old wire alone.

642] A piece of the same wire was wound about 150 times round one of the slips of glass, and was laid flat on another of these slips which lay flat on a table.

The shock of these tubes seemed rather greater when received through this wire than when received simply, but the difference was not considerable, but it seemed evidently less than the shock received through the new wire.

643] The wire was taken from off the reel with the slips of glass, and all except a small part of it stretched round the garden in 14 rounds. The shock of the above-mentioned tubes received through this wire felt plainly greater than that passed through the wire stretched by the silk threads, and much greater than the plain shock.

The shock passed through the sat. sol., wires in contact, seemed about equal to the plain shock.

The spark passed through garden wire seemed rather redder than that through the silk wire, but the difference was not remarkable.

The spark passed through garden wire seemed about as strong as that through about 8 of an inch of saturated solution, but sensibly redder.

644] The reel was altered, and some copper wire silvered stretched upon it.

There were 12 rows of glass bars and 42 rounds of wire on each row, therefore whole length of wire = 88.1 × √√2 × 12 × 42 = 62790 inches. This weighed 5747 grains. Consequently there are 10.93 inches to 1 grain.

The shock received through this wire felt vastly stronger than the simple shock; the shock of tube 2 received through the wire with electrometer at 11 seeming little less strong than the simple shock with the same tube and the electrometer at 13, but considerably stronger than with electrometer at 11.

645] The above-mentioned wire compared with sat. sol. by sound.

1.46. Seemed more brisk. The light of salt water white, the other very red. 1.7 Do

9.5

doubtful.

I believe rather less, certainly a sharper sound, but I believe rather

646] 74 of sat. sol. in tube 17 is equivalent to 29623 inches of copper wire, 9.984 inches of which = 1 grain,

7.25 of sat. sol. in do. = 62790 of copper wire, 10.93 of which = 1 grain*.

RESULT.

647] 1773, p. 92 [Art. 557]. The connecting wire to the two plates of 9-3 inches contains 14 inc. el. The connecting wire to the rosin plates of p. 86 [Art. 554], should contain rather more in proportion to its length than this, id est, rather more than 28.

By p. 93 [Art. 557], the 4 rosin plates seemed to contain about inc. el. less when placed close together than at dist. Let us therefore suppose that the charge of 2 rosin plates placed close together with connecting wire between them exceeds twice the charge of 1 plate by 28 inc. el., and that the charge of 4 plates exceeds 4 times the charge of 1 by 2 times that quantity, or 7 inc. el. Let us suppose, too, that the charge of the 2 double plates A & B with connecting wire exceeds twice the charge of 1 by 28.

N.B. By inc. el. is meant circular inches of electricity.

[These logarithms are correct only to three places of decimals, they should be 0.1875 and 9.8122. See Note 35.]