124 Mr. Snow Harris on LiMnins. Conductors 



'is 



Now the separate pieces of leaf-gold thus placed, may be taken 

 to represent detached conducting masses fortuitously placed 

 along the mast and hull of a ship. 



Exp. 2. Let a thin continuous line, m, n, be passed through 

 the separated pieces, and a dense accumulation discharged 

 over the whole, as in the preceding case. The effect will be 

 as represented in fig. 6. : the discharge will be confined to the 

 line of least resistance; and we may perceive in this, as in the 

 former case, that those pieces, or parts of pieces, out of the 

 track of the discharge, are not affected ; thus a part only of the 

 piece g is destroyed, also of the piece i, whilst other pieces, 

 bi d, Cijl /, which in the former case, where the continuous 

 line, a, b, was not present, were blackened by the discharge, 

 remain here perfect. 



Exp. 3. If the continuous line A, B (figs. 7, 8) be assisted 

 by other comparatively short collateral branches, as d e^ d c, 

 having one common connexion at B, then a discharge which 

 would destroy the line A, B, will divide upon these auxiliary 

 lines, and the part d, B will either escape, or the whole will 

 suffer together. 



Exp. 4. Pass a discharge over a strip of gold-leaf, as A, 

 fig. 2; every part of it, as indicated by the last experiment, will 

 participate in the shock ; and if it be of uniform density and 

 thickness it will be everywhere equally affected, so that one 

 portion will not be destroyed without the whole. This result 

 will be readily distinguished from that represented at d and z, 

 fig. 5, where the masses lie across the track of the discharge. 



The diagrams here referred to, are copied from the actual 

 effects of the electrical discharge in the way above mentioned. 



18. These experiments are instructive. They evidently 

 prove, that an electrical explosion will not leave a good con- 

 ductor, constituting an efficient line of action, to fall upon 

 bodies out of that line. Mr. Sturgeon's assertion that a con- 

 ductor on a ship's mast would operate on the magazine is 

 therefore quite unwarranted. Besides, we have many instances 

 of the masts having been shivered by lightning into the step, 

 whilst acting as partial conductors, without any such conse- 

 quence; as happened in the Mignonne in the West Indies, 

 the Thetis at Rio, the London, Gibraltar, Goliath, and many 

 others. Instead, therefore, of a conductor on the mast being 

 dangerous, it is absolutely requisite as a source of safety to the 

 ship, by confining the discharge to a given line and leading it 

 to the sea. 



19. It was from a careful consideration of the common ef- 

 fects of lightning, and from such experimental facts as those 

 above mentioned, that I was led to suggest the propriety of 



