296 



NATURE 



\yuly 25, T889 



to the conductor, and about 70 feet distant from it in a direct 

 line : leaving the iron cover and its wood lining untouched, it 

 broke through the masonry, hurling portions of the brickwork 

 to a distance of 25 feet along the flat roof ; then, bridging over 

 3 or 4 feet of air, it reached the iron hand-rail of a spiral wooden 

 staircase leading into the house. Incidentally, it may here be 

 noted that this house is the nearest to the factory, which bristles 

 with lightning-conductors at every available point ; and, further, 

 that the charged cloud would in its course pass over the portion 

 struck before it could reach either the factory conductors or that 

 on the house itself. Passing down the hand-rail for 11 feet, it 

 reached a point at which metallic continuity ceased, owing to 

 the interruption of the hand-rail ; here it appears to have divided, 

 a portion leaping along 5 feet of the wall and stripping off the 

 plaster in patches, until it reached the second section of the 

 hand-rail ; through this it passed harmlessly, and then flew through 

 2 feet of space to an iron rod resting in the corner of the wall, 

 perforating a wooden "stair-rise" on its path. The other por- 

 tion discharged through about 7 feet of space in the angle of the 

 wall direct from an iron standard, supporting the first hand-rail, 

 to the iron rod ; here, reuniting with the other portion, the 

 whole current broke through the wall into an adjoining bed- 

 room, and thence through the wood flooring to a sitting-room 

 beneath. It may be observed that the spiral staircase at one 

 time communicated with the ground-floor, but has since been 

 filled in and covered over ; there is no evidence, however, to 

 show that any portion of the charge made earth in this direction. 

 Within a few feet of the point where the ceiling was penetrated 

 (but round a corner) is a broad staircase with a wooden hand- 

 rail, supported by uprights of iron rod placed about 4 or 5 inches 

 apart from top to bottom ; but this path was not taken. Having 

 penetrated to the sitting-room, as above described, it appears to 

 have passed in a direction precisely opposite to that ultimately 

 taken, and to have circled in a spiral manner around one of two 

 brick pillars at that end of this room, and having laid bare the 

 bricks in several places, but chiefly at a height of 4 feet from 

 the ground, it passed across the room in which Mr. Viney was 

 sitting with seven members of his family and friends, and up- 

 wards to the ceiling at the opposite end. Breaking through the 

 ceiling (which is, as usual in these houses of wood, not of plaster), 

 it burst up the boarding and singed the matting above, and 

 again descended, but now into the dining-room on the other side 

 of a partition wall. Here, darting diagonally downwards to the 

 opposite wall and stripping off" a large area of plaster in one 

 place, it made for an electric bell suspended in the centre of this 

 wall, fused the contacts, and apparently passed along the con- 

 necting wire to the battery, of which two out of six cells were 

 shattered, and finally escaped through a return wire to a cook- 

 house 30 yards distant in the compound. Strangely enough, 

 these wires, although thin, are not fused, which serves to 

 strengthen the opinion that only a portion of the charge pene- 

 trated at least into the lower rooms, even if the whole entered 

 by the spiral staircase. 



The path of the discharge from the first entrance into the 

 sitting-room to the final exit by the bell-wire is somewhat in- 

 explicable — especially the circuit of the brick pillar, which is 

 said to be of solid masonry, with no iron core ; it is true that a 

 sewing-machine was standing on the further side of the pillar, 

 but although within a few inches of the patch denuded of plaster, 

 it appears to have been unaffected. Again, there were several 

 metallic objects in the room — an iron chair close to the above- 

 mentioned pillars, and a square horizontal piano with the 

 strings parallel to the line of discharge, yet both were untouched ; 

 the occupants of the room also were practically in the same line, 

 but were perfectly uninjured. Then, too, there was apparently 

 nothing to lead the lightning through the ceiling boards to gain 

 access to the dining-room in preference to an open door a few 

 feet distant. And, lastly, it did not pass across the latter room 

 in a direct line to the electric bell, but struck the wall about 5 

 feet away, tearing away the plaster and leaving upon the bricks 

 a netted marking recalling the branching discharges of a torrent 

 of sparks from an induction-coil or Wimshurst machine ; near 

 this point, but a few inches to one side (the bell side) and in 

 front, was a pendent iron chain, which may have determined the 

 charge in that direction, but shows no sign of having been 

 touched ; and immediately beneath the spot through which the 

 lightning entered the room was standing a member of the 

 household, who also escaped with a severe shock to the nerves 

 and a temporary tingling sensation. Attached to the affected 

 pillar in the sitting-room was a cuckoo clock, and this alone in 

 that room appeared to suffer ; the weight chain was taken in 



transit, and the clock began vigorously to chime, which it has- 

 refused to do ever since. 



Mr. Viney happened to be facing in such a direction that he 

 could watch the progress of the discharge. He describes the 

 effect as that of an intensely brilliant ball of yellow fire, about 

 6 or 7 inches in diameter, which passed from one end of the 

 room to the other at a pace just sufficiently slow to allow it to- 

 be readily followed by the eye ; about half-way across, it 

 appeared to be momentarily checked, and then, seeming to burst 

 with a deafening report which shook the whole house, it 

 scattered and passed onward. 



About certain points he is absolutely certain : there was no 

 premonitory warning, no sound of a brush discharge or odour of 

 ozone, the first intimation being the entrance of the fire-ball 

 itself. Again, the direction taken was from the staircase to the 

 bell (that is, from cloud to earth), and the direction was uniform, 

 and no second ball was seen to enter from the opposite side to- 

 meet the first and so produce the apparent explosion, nor after 

 the concussion was there any other phenomenon than the passing 

 on of the ball. 



Again, it has long been known that the passage of high ten- 

 sion discharges through mixtures of oxygen and nitrogen induced 

 combination of these elements ; I therefore asked Mr. Viney as 

 to the after appearances, and as to the presence of unusual 

 coloured gases, or of a suffocating sensation. He at once said 

 that the whole house seemed to be filled with an orange-coloured 

 gas (mixed, of course, with clouds of dust), the breathing of which 

 was perfectly stifling, and was equivalent to inhaling the fumes 

 from burning sulphur. I have since asked him to report upon 

 a sample of nitrogen tetroxide highly diluted with air: he 

 declared that the gas in his house was of a brighter orange 

 shade, and of a somewhat similar yet not identical odour ; on 

 presenting him, however, with a stronger mixture, he was quite 

 confident that both in colour and in smell the two gases were iden- 

 tical. I am here practically confined to my own library for 

 books of reference, but am not aware that this observation has 

 actually been made before, although, as above stated, theory has 

 long since ruled that such a reaction must occur during the 

 electrical discharges of a thunderstorm. But the proof is here 

 not only that the reaction does occur, but that a very large 

 proportion of the oxygen in the atmosphere immediately sur- 

 rounding the path of the flash must be converted into oxides of 

 nitrogen. 



The appearance of the fire-ball was only within the house. 

 The discharge as seen from my position appeared as an almost 

 straight ribbon of light ; owing unfortunately to intervening 

 trees, the flash could not be traced quite to the house, or the 

 question as to the branching of the lightning on entering the 

 house might have been definitely answered. 



Several points seem to be thus clearly brought out, e.g., inter 

 alia, (i) the futility of partial lightning-conductor protection; 

 (2) the apparently erratic nature of the discharge ; (3) the apparent 

 conversion of the instantaneous discharge of ribbon-lightning into 

 the slower travelling modification of globe-lightning ; (4) the 

 form.ation of large volumes of oxides of nitrogen by the lightning 

 discharge. 



The above recorded observations might appear to add colour 

 to an authoritative statement on p. 629 of Nystrom's 

 " Pocket-book of Mechanics" (Philadelphia and London ; re- 

 vised and enlarged edition of 1886), where, in speaking of certain 

 explosions, the author (or at least the printer) lays down that 

 " the explosion of nitro-glycerine is instantaneous like that of 

 electricity passing between two points, decomposes a small por- 

 tion of the air, and explodes the nitrogen by concussion, which 

 makes the electric spark. Thunder and lightning are explosions 

 of a kind of nitro-glycerine formed by electricity in the air." 

 We might even be led to indorse this both novel and ingenious 

 explanation could we but bring ourselves to reverse existing 

 notions as to the properties of matter and the laws of thermo- 

 chemistry, and, at ttie same time, reconstruct the principles of 

 electrical science upon a suitable basis. 



The accumulation of authenticated cases such as the above is 

 of value in throwing more light upon the vagaries of the " electric 

 fluid" at enormous potential, and in helping to elucidate the 

 laws under which it acts, and hence the laws which should 

 govern the protection of buildings ; and it is in the hope that 

 this account may form a small item in the mass of evidence, that 

 I venture to forward it for publication. 



Walter G. McMillan. 

 Chemical Department, Shell Factory, 

 Cossipore, Calcutta. 



