a7id the effects of lightning on H.M.S. Rodney ^ S^c. 119 



my conductor, the thickest part of it would have become red- 

 hot. His reasoning, in fact, amounts to this ; an explosion 

 of lightning having slightly fused a small brass sheave, weigh- 

 ing 4 ounces, and having failed to fuse a short copper funnel, 

 therefore had it fallen on a rod of copper of one inch in dia- 

 meter, and 200 feet long*, that rod would have been rendered 

 red-hoi. 



This, it must be allowed, is a somewhat amusing kind of 

 special pleading, quite unprecedented, 1 believe, in any paper 

 on science. 



7. The author wishes to strengthen his deduction, such as 

 it is, by adverting in a foot-note to the case of a small brig 

 struck by lightning, in which some part of a chain conductor 

 is supposed to have been fused ; how much is not known, " as 

 the lower part fell overboard." The statement is given with- 

 out any quoted authority, and is altogether deficient in the 

 very information most required, viz. the size of the chain^ and 

 how much of it was fused. Let us, however, take it upon the 

 author's own ground, and suppose the conductor to have been 

 such as is commonly used in the merchant service, — that is to 

 say, links of iron wire of about one-fourth of an inch in dia- 

 meter, united by rings, a kind of conductor very easily dis- 

 jointed and fused at the points of junction by lightning; — the 

 reasoning then stands thus : because a shock of lightning fused 

 and disjointed some unknown portion of a lightning chain in 

 a merchant brig, therefore the same shock, had it fallen on a 

 solid copper rod of one inch in diameter and 100 feet long, 

 would have rendered that rod 7'ed-\\ot. 



7. The fallacy and entire worthlessness of such reasoning, 

 seems not altogether to have escaped Mr. Sturgeon's notice, 

 as appears by his amplification of the above effects ; thus on 

 entering upon the comparison of the effects of lightning, he re- 

 sorts to a sort of wholesale dealing, and leads the reader to con- 

 clude that the entire sheave in the Rodney and all the brigs' 

 conductor underwent fusion. But even if it were so, no such 

 conclusion as that above mentioned is admissiblef? especially 

 in reference to a continuous and massive conductor termina- 



* This is tiie equivalent of my conductor on the main-mast of such a 

 ship as the Rodney, taking it at its least value. 



f " Were there no other data than those of the fusion of the metallic 

 sheave in the Rodney and the fusion oithe chain-conductor in the brig Jane," 

 &c. &c. 



" The impressions which these facts convey to the mind are too definite 

 to be easily misunderstood ; they clearly imply that either of the discharges 

 vv-hich struck the Rodney or Jane would have rendered the thickest part 

 of Mr. Harris's conductors sufficiently hot to ignite gunpowder," &c.&c. — 

 Sturgeon's Memoir, sec. 204. 



