1 150 titions to consist of plates of white glass inc. thick, which is about 2 times as much as my battery, that being = 451000 inc. el. 615] Tried with the 2nd leather torpedo, new covered, in large was just sensible in elbow. trough full of water, the torpedo laid flat as in figure, the electrical organ being (as supposed) 3 inches under water. If torpedo was tried out of water with 1 row to 1 comm. to 7 and touched with hands in usual manner, the shock was just felt in hands, and if touched with metals, Tried under water in above-mentioned manner with 7 rows el. to 4, the upper surface being touched with the pestle of a mortar held in one hand, the other hand dipt into water as far as wrist, a shock in the wrist of the hand in the water I believe full as strong as the former. The place where the hand was dipt into water was about 11 inc. from the front of the fish, and conseq. about 14 from elect. organ. Tried in the same manner as before, except that the fish lay in an open wicker basket*, just big enough to receive it, and which had been soaked for some days in salt water. The shock seemed much the same. Holding hand in water in same manner as before without touching torpedo-no sensation. With three rows to 1 out of water, the shock was stronger if I touched convex side with one hand laid flat on elect. organs than if I touched flat side in same manner, but the difference was not great. Charge of 7 rows el. to 4 is to that of 1 row el. to 11 as 19.6 to 1. The water appeared by its spe. gra, to contain of salt. * [Art. 421.] RESISTANCE TO ELECTRICITY. 616] Comparison of conducting power of salt and fresh water in the latter end of March and beginning of April, 1776. Tried with Nairne's last battery, 6 jars being chose, each of which held very nearly the same quantity of electricity; the wires run into the bent ends of the tubes being made to communicate with the outside of the battery, and the wires run into the straight ends being fastened to separate pieces of tinfoil. The six jars were all charged by the same conductor: the communication with that and each other was then taken away, and the jars discharged through the tubes, one after the other, by touching the abovementioned bit of tinfoil by metal held in one hand, and the wire of the jar by metal held in the other hand, the shock being received alternately through each tube. Straw electrom. = 4. scarce sensibly just sensibly less 1= Th. = 57. [Resistance = 390000 Ohms. †] Resistance of 4.7 inches in tube 15 supposed equal to 407 in 14. Therefore sat. sol. conducts 8.6 times better than salt in 69 of water. Therefore sat. sol. conducts 8.94 times better than salt in 69 of water. [Saturated solution of sea salt.] +[The resistance of the saturated solution in Ohms. calculated from the measurements in Art. 635 by Kohlrausch's data, is given for each tube within brackets to indicate the absolute value of the resistances compared.] Exp. 3. A new saturated solution and solution in 69 of water made and tried in tubes 15 and 14. [R. = 390000.] Therefore new saturated solution conducts 9.61 times better than new solution in 69. Exp. 4. Salt in 69 of water compared with salt in 999 of water in tubes 22 and 23. [R. = 1230000.] Resist. 4.1 in tube 23 supposed equal to 41·1 in 22. Therefore salt in 69 conducts 9.57 times better than salt in 999. Exp. 5. Salt in 999 compared with distilled water in tubes 12 and 20. [R. = 462000.] 3. 78 1.2 1.4 1.05 supposed right. Therefore salt in 999 conducts 36-3 times better than distilled water. 1.9 3.3 2.55 The distilled water changed for rain water. Electrom. 3. = Th. = 58°. sensib. greater. Therefore rain water conducts 2.4 times better than distilled water, or 15.2 times worse than salt in 999. it. The rain water changed for distilled water with zooo of salt in Therefore salt in 20000 of distilled water conducts [3.67] times better than distilled water, or 9.92 worse than salt in 999. [6] Saturated solution and salt in 69 of water (the new solutions) compared in the same manner, only using the jars 1 and 2 instead of the battery; with the tubes 5 and 17. Therefore saturated solution conducts 10:05 times better than salt in 69 of water. 618] The electricity of the 6 jars was found to be as much diminished by being communicated to 3 rows of the battery as that of 1 row is by being communicated to 4 rows, therefore quantity of electricity in the 6 jars is to that in one row as 3 to 4. Exp. 7. Saturated solution and salt in 69 (the new solutions) tried in the same manner with battery; 1 row being electrified to 2, and its electricity communicated to remaining rows, and one row used at a time. Tried in tube 5 and 17. [R. = 25300.] 3.95 supposed right. Therefore sat sol. conducts 10-31 times better than salt in 69. Exp. 8. Saturated solution compared with salt in 29 in tubes 22 & 23 with Nairne's jars. The bore of that part of tube 23 which was used is supposed greater than that of whole tube together. Therefore sat. sol. conducts 3.51 times better than salt in 29 of water. Exp. 9. The solution in 29 diluted with 11 of water, id est, solution of salt in 69, compared with sat. solution in same tubes. Electrom. 1. Th. 63. [R. = 65000.] 23 22 = about as much less. = Therefore sat. sol. conducts 7.79 times better than the diluted solution, and the diluted solution conducts 2.2 times worse than solution in 29. Exp. 10. Saturated solution compared with salt in 69 in same Therefore sat. solut. conducts 9:02 better than the solution in 69. 619] Examination whether salt in 69 conducts better when warm than when cold. Salt in 69 in tube 17 placed in water; solution in 29 in tube 23 out of water, the distance of wires in tube 17 being not measured, but remaining always the same. Therefore salt in 69 conducts 1.97 times better in heat 105 than in that of 581*. 620] Examination whether the proportion which conducting power of sat. sol. and salt in 999 bear to each other is altered by heat. Sat. sol. in tube 15, salt in 999 in tube 19, both in water; distance of wires in tube 15 not altered. Therefore the proportion seems very little altered by heatt. 621] Jan. 1, 1777. Salt in 2999 of water compared with water distilled in preceding summer in tubes 12 and 20. 1.5 43.5 1.95 1.4 Electrom. = 44. rather greater. Column of 1.6 in tube 20. plainly less. Supposed equal to 43.5 in tube 12. greater. Therefore allowing for different bores of tubes, salt in 2999 conducts 24 times better than distilled water. [By the experiments of Kohlrausch, this ratio would be 1.59. and Note 33.] [This agrees with the results of Kohlrausch.] See Art. 691 |