of Danger in Torpedo Experiments. 77 



It may be thought that in these calculations I have been 

 unnecessarily particular, as, for instance, in allowing for 

 differences of temperature, &c; but I have thought it best to 

 be precise. There will always be a margin of uncertainty 

 in such calculations, for the constants used can only be 

 regarded as approximately correct; but I have been 

 anxious not to add to that uncertainty by any laxness in the 

 use I have made of the constants. 



Doubtless the Torpedo Inquiry Board has good reasons 

 for not having tested the foregoing purely theoretical con- 

 siderations by a series of experiments, which would have 

 decided the question of the strength of the sea-ceil current. 

 Perhaps it may even yet adopt that course. 



In the meantime, I proceed to give the result of some 

 experiments recently made by Messrs. Geo. S. Caldwell and 

 Geo. Smibert, both of the Post and Telegraph Department, 

 and both well known as practical and scientific electricians. 

 Mr. Caldwell's previous experience as an electrician had con- 

 vinced him that, under certain circumstances, the current 

 from a sea-cell was of considerable magnitude. Hence, from 

 the time of the accident he suspected, and he is the only 

 person I know who from the first did suspect, that the 

 accident might have been caused by a sea-cell cur- 

 rent. Instead, therefore, of regarding as decisive the 

 negative results of certain experiments we have heard 

 of through the daily papers, these gentlemen resolved to 

 test the question for themselves. They did not intend to 

 publish the results, but, at my request, have kindly placed 

 them at my disposal. 



The experiments were made from on board R.M.S. 

 " Malwa," as she lay alongside the Railway Pier at Wil- 

 liamstown. A zinc plate, 7 feet by 3 feet, was lowered over 

 the side of the vessel, well clear of the hull ; and, to com- 

 plete the circuit, a small portion of the main rail of the ship 

 was scraped clean of paint and rust, and touched with the 

 end of the wire. After some preliminary tests with the 

 galvanometer, eight fuses were experimented on, with the 

 following results : — 



1. Exploded on first contact through about 8 yards of 

 wire. 



2. Exploded through the same length, but only after a 

 considerably longer contact, showing a decided difference in 

 the sensitiveness of the fuses. 



3. Exploded through 10 yards. 



