676] [Table given in Art. 383.] The white jar and cyl and the 3 green cyl. are corrected for the spreading of the electricity in the same manner as the flat plates, but the 2 therm. tubes are not. 677] On the compound plates*. P. 60, Art. 534. The 3 plates A, B and C placed over each other with bits of lead between contained 8.9 inc. el. less than K or L, therefore its charge =74 inc. The 3rd part of the charge of A, B, or C is 72.6 inc. The coatings taken from the 3 plates A, B, & C, the plates placed close together and the outside surfaces coated with circles 6-6 in diam. 544, P. 75, it contained 7.5 inc. less than D + E + F. 546, P. 77, 6 less. By mean it contains 67 less, therefore charge = 74.5. The thickness of the 3 plates together is 6309. The computed charge of a plate of that thickness with a coating 6-6 in diam. supposing the el. to spread 07 inc. is 9.00, and the real charge of such a plate according to the mean ratio of the real and computed charges of D, E, and F is 74.2. 678] A plate of exper. rosin about 8 inc. square was pressed out, thickness irregular, but at a medium about ·122. It was coated with circles 6.61 in diam.t Art. 548, P. 79, its charge = K+D+E × 1 1 The real charge of this plate is to its computed, supposing the el. to spread 07 inc., as 2.89 to 1. The charge of this plate is the same as that of a glass one 345 thick, supposing ratio of real and computed charge the same as in A or B. 679] The coatings being taken from this plate it was included between the plates B and H, and the outside surfaces coated with circles of 6.6 in diam. 552, P. 83, it cont. 6.9 inc. el. less than K, 6.5 5.2 less than D+E+F, by mean it contains 75.5 glob. inc. The charge of plate glass of the same sort as Nairne's 634 thick (id est, equal to the sum of the thicknesses of the two glass plates and a glass plate equiv. to the rosin) = 73.3, supposing the el. to spread the same on this plate as on the rosin. 680] [Same as Art. 368.] 681] By res. P. 5 [Art. 654] a globe of 12 inc. contains as much el. as a circle of 18.5*, therefore by Prop. XXIX. p=13, therefore By 1st exp. 1772 [Art. 473] the proportions were thus •811 •859 ⚫899 1+ By 2nd exp. [Art. 475] $798 •840 .894 682] The charges of the following bodies are supposed to bear the following proportions to each other‡. Charge by theory of wire short] cyl. = length cyl. ::: N. L. 2 length .998 their charge = 1.008. long cyl. is between 896 & 1.573 that of globe being one, -894 1.619 and if charge cyl. is supposed to be to that of globe whose diam. (-887 1.469 1.006 This ratio approaches about 5 times nearer to the first proportion than the 2nd§. The area of the oblong is the same as that of the square, and their charges are very nearly the same. The charge of a square is to that of a circle whose diam. = side square as 1.153 to 1 ||. * [Note 35.] + [Note 21.] [Exp. vII., Art. 281. The numbers here are different. See Art. 478.] $ [Note 12.] [This ratio is given in Art. 283 as 1:53 by a mistake of the Editor in copying, see Note 22.] 93 683] In exper. P. 11, 1772 [Art. 477], the large wire should contain about less el. than if its diam. was double the small ones. Allowing for this, the charges of the large wire at 36, 24 & 18 inc. dist. should be between the two following proportions: but I believe ought to approach about 5 times nearer to the former. The observed proportions are * RESULTS [OF EXPERIMENTS ON RESISTANCE OF SOLUTIONS]. 684] Resistance of Pump-water is that of rain water*. Salt in 1000 of rain water 9 times less than 685] A shock is diminished very nearly the same, but if anything rather more, by passing through 9 tubes, 37 inches of which hold 3373 grains of, than through one tube, 37 inches of which hold 3480 grains of t. 686] A shock is as much diminished in passing through 6-8 inches of a tube, 37 inches of which hold 567 grains, as through 444 of one 37 inches of which hold 3480. So that resistance should seem as 1.03 power of velocity +. 688] Resistance of sat. sol. S. S in 99 of distilled water is 39 times greater than that of the sat. sol. Resistance of distilled water is 18 times greater than that of sat. sol. in 99 of distilled water§. 689] Experiments in 1776 and 1777. By N. B. It is not said what water the solutions were made with. the comparison of salt in 999 with salt in 20,000, it should seem either that they were not made with distilled water, or that some mistake was made in the experiment. 690] In Jan. 1777, salt in 2999 conducted about 70 or 90 times better than some water distilled in the preceding summer, or about 25 or 50 times better than the distilled water used in the year 1776 *. Salt in 2999 conducted about 25 times better than salt in 150,000. 691] Salt in 69 conducts 1.97 times better in heat of 105° than in that of 58°1 t. The proportion of the resistance of sat. sol. and salt in 999 to each other seems not much altered by varying heat from 50° to 95° ‡. 692] Salt in 150,000 seemed to conduct rather better than the same water deprived of air by boiling in the same vial in which it was kept, and cooled quick in water to prevent its absorbing much air. But the difference was not more than might arise from error of experiment §. 693] Distilled water impregnated with fixed air from oil of vitriol and marble conducted 2 times better than the same water deprived of its air by boiling||. 694] Conducting power of other saline solutions compared with that of salt in 29 of water¶. |