Part of a Letter from John Huxham, M. D. F. R. S. to W. Watson, F. R. S. in Relation to the Effects of Lightning at Plymouth

III. Part of a Letter from John Huxham, M.D. F.R.S. to W. Watson, F.R.S. in relation to the Effects of Lightning at Plymouth. Read Jan. 9, Sunday, December 15, 1754, twenty-five minutes after one P.M. a vast body of lightning fell on the great hulk at Plymouth-dock, which serves to hoist in and fix the masts of the men of war. You may have some idea of it by this scheme, which was sent me by the lieutenant of the Peregrine, which lay close by the hulk, who saw it. It burst out about a mile or two to the westward of the hulk, and rushed with incredible velocity towards it. The piece of the Derrick cut out was at least eighteen inches diameter, and about fifteen or sixteen feet long: this particular piece was in three or four places begirt with iron hoops about two inches broad, and half an inch thick, which were completely cut in two by the lightning, as if done by the nicest hand and instrument. Two days after the accident I went on board myself, and examined the matter, and have added what I further observed. The lightning was immediately succeeded by a dreadful peal of thunder, and that forthwith by the most violent shower of hail I ever saw in England, which fell only in and about this town, for a mile or two: there was very little of it at the dock, though only two miles distant. The hail-stones were as big as small nutmegs, much of the shape of some sort of beads cut into squares, a kind of a dodecahedra, quite pellucid as the clearest ice, with only a white speck in the middle, about the bigness of a pea. But that, for which I chiefly mention the whole, is, that they were all very nearly of the same bigness and figure. I examined thousands of them, as well as many other persons, who all found this similarity in size and form: they measured, immediately after they fell, near two inches round. I think this great uniformity in the shape of the hail must be owing to some saline principle, that determined the configuration. The uniform stellate form of snow is very remarkable, and seems owing to the nitro-aerious salt. Every one knows salts shoot into particular forms: and when the salts are compounded, the figure participates of both, as is seen in what is called the quadrangular nitre. December 15, half past 1, P. M. wind S. W. A to B, Cut all away by lightning. C, The mast sprung by ditto, into the heart. D, The lashing, forced by the shock off the Derrick's end, tho' the lashing round the mast was sound and fast. E, The Derrick, (or Direct), out of which a piece from A to B was cut off by the lightning: round this piece were three or four iron hoops, as described, which were cut asunder. The Derrick was at least eighteen inches diameter. F, The chain-pump, split quite thro' by the lightning. I do not know what the gentleman means by this. The wind was W. S. W. the lightning came from due west. IV. A remarkable Case of a morbid Eye: By Mr. Edward Spry, Surgeon, at Plymouth, in Devonshire. Read Jan. 9. June 1751. MARY the wife of Thomas Smallridge, a mariner of Plymouth, complained to me of a violent pain in her left eye, and sometimes of very acute pains in the temple of the same side, with some defect in her sight. She also imagined that her eye was bigger than ordinary; but, upon inspection, it appeared no bigger than the other.