Lectures on electricity / by James Ferguson, F.R.S.

  • James Ferguson
Date:
1825
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on electricity / by James Ferguson, F.R.S. Source: Wellcome Collection.

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    gether at the joinings ; and the top part, which is sharp pointed, may be about two or three feet long, and made of copper. Or, where there are leaden spouts on the sides of the building, the metal needs only to go from the point to any of these spouts, and a rod or bar go from the bottom of the spout into the ground, so that the whole may be done at a very small expence. The part of the metal that goes into the ground should be turned away from the foundation of the building and terminate in moist earth.27 It is amazing to think how great a flash of lightning may be accumulated into a small wire, and conducted thereby. In confirmation of this, I shall here take the liberty to transcribe an account from Dr. Franklin’s book of Experiments and Observations on Electricity j2* printed in London, A. D. 1769. “Being, (says the Doctor) in the town of New- bury in New England, in November29 last, I was shewn the effect of lightning on their church which had been struck a few months before. The steeple was a square tower of wood reaching seventy feet up from the ground to the place where the bell hung, over which rose a taper spire of wood likewise, reaching seventy feet higher, to the vane of the weathercock. Near the bell was fixed an iron hammer to strike the hours ; and from the tail of the hammer a wire went down through a small gimlet- hole in the floor that the bell stood upon, and through a second floor in like manner ; then, horizontally under and near the plastered ceiling of that second floor, till it came near a plastered wall; then down by the side of that wall to a clock, which stood about twenty feet Note 27. An improved metallic preserver has lately been suggested for the use ol ships. It consists of thin metallic wire, wove into a cord, which, by its flexibility, allows the mariner to adapt it to any part of the rigging of the vessel. Note 28. Pages 162, 163, 164.-»-Author. Note 29. Meaning November, in the year 1754.—Idem