1884.] 
AMERICA:^ AGRICULTURIST, 
15T 
Lightning and Lightning Eods. 
OBAHaE JTXDD. 
Spring has come and “ the voice of the lightning rod 
man will be again heard in the land,” as he goes up and 
down among farmers, seeking whom he may devour. In 
autumn, when muttering thunders retire southward with 
•the sweet-voiced songsters, the lightning ” regulator” 
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n, >^ 50 n 
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s 
Fig. 4. —THE MAIN DBIVE FLOOR, 
■calls in his forces, his traps, his wagons and horses, dis¬ 
posing of the latter, or putting them out to hoard for the 
winter if the state of the market does not favor a sale. 
But as soon as the zigzag streams of light dart athwart 
the spring clouds, and awaken the fears of the neiwous, 
he, like the circus man, gathers his retinue and takes 
possession of the field of operations decided upon the 
previous year, or selected during the winter’s leisure, 
with his vocabulary re-enforced by some new arguments 
and his wagon with one or more newfangled “points,” 
“ angles,” “ insulators,” “ rods,” “ joints,” etcetera. 
Lightning as seen, is the light produced by the swift 
passage of electricity through the air from cloud to cloud, 
or from the clouds to the earth, or the earth to the 
clouds, or both. Its velocity is almost inconceivable, 
equal to going seven times around the world between 
two ticks of a three-foot clock pendulum; or, say about 
five hundred times faster than a ball flies as it leaves a 
heavily-loaded rifle.—The air does not conduct electricity 
through it, but it forces its way along, driving the air 
particles together, and, so to speak, squeezing the heat 
Fig. 6.—MIDDLE OH FEED FLOOR. 
out. If we push a tightly-fitting rod down a gun barrel, 
crowding the air suddenly into a small space, the air will 
give out so much heat as to become red hot and set fire 
to a piece of tinder in the bottom. So we may suppose 
the swift lightning pushes the air together before it un¬ 
til it becomes brilliantly red-hot (lightning,) and when 
much air is compressed before it, it darts off until more 
air is compressed in the new line and then it shoots an¬ 
other way, and thus we have its zigzag course. This 
driving and beating the air produces the sound we call 
thunder. We get sound by agitating the air when beat¬ 
ing a drum-head, or vibrating the strings of an instru¬ 
ment, by exploding powder in it, etc. The more vio¬ 
lent agitation by the swift lightning produces the loud 
thunder, though a lightning stream of electricity is so 
small at any one point that it shakes the air less than a 
heavy cannon charge of powder. (Ttiunder is seldom 
heard ten miles, while a battle has been heard forty 
miles or more). The rolling of thunder is caused by 
sounds coming in from different distances one after an¬ 
other, as the electricity darts from cloud to cloud, farther 
or nearer from us, a thunder sound being produced be¬ 
tween each pair of clouds. It is as if a score or more of 
cannon, each a little further oil’, were all fired at the 
same moment; we would have by the reports coming 
one after the other a rolling sound just like thunder. 
Light comes almost instantaneously from a distpnt 
point, while sound takes nearly five seconds to come a 
mile through the air. If we see the flash of a cannon 
and begin counting one, two, three, only as fast as a 
three-foot pendulum ticks, about the time we count five 
the sound of the cannon will arrive. After a sharp flash 
of lightning count as above, and the real lightning cloud 
is as many fifths of a mile away as you count seconds. 
If you count four or more, you may know that that light¬ 
ning cloud is at a safe distance. If coming towards you, 
the thunder will more quickly follow the lightning; if 
going from you you wili count more at each successive 
flash ; if counting about the same number, it is going 
by. Understanding this will help quiet nervous people. 
While electricity is not conducted by air, but jumps 
across, or through air spaces, producing lightning and 
thunder, it will go quietly along or through the metals, 
passing from one particle to another. A quantity of 
electricity that would rend the air, produce blinding 
lightning and deafening thunder, would run through or 
along a copper rod no larger than your finger so quietly 
that you would not perceive it. It would do the same on 
an iron rod a little larger. Iron is a good conductor of 
electricity, and copper and pure silver are still better. A 
tube filled with water, if large enough, would conduct the 
electricity, and so would a rod of wood if its pores were 
full of water; moist flesh will do the same, but not 
nearly so well as the metal. The electricity would not 
go through a glass rod at all, nor through a wax one, nor 
through a dry stick, or feathers. Remember that there are 
good conductors, as silver, copper, iron, etc.; poor ones 
like wet wood, the bodies of animals, cotton, etc., and 
non-conductors like glass, wax, and very dry wood. This 
will enable us to understand lightning rods further on. 
The condensation of vapors in forming clouds de- 
velopes a good deal of electricity. The clouds float on 
the non-conducting air, and the excess of electricity can¬ 
not get away. Another cloud coming near, having less 
electricity, some of the excess jumps across the inter¬ 
vening air space, producing lightning and thunder as it 
forces itself through the resisting air. But now suppose 
the over-charged clond gets near the earth. Some of the 
excess of electricity will strike off to the ground tearing 
its way down straight through the air, or zigzag if th6 
distance be far. This clond being thus relieved, other 
over-charged clonds in the vicinity may send over to it 
their excess, and there will be sundry lightnings, though 
usually they all join in sending the one grand charge to 
the earth, and there is quiet until more electricity accu¬ 
mulates.* In a continuous rain, enough electricity runs 
down the rain-charged air to stop heavy discharges. 
Now suppose one of these clonds passing over us has 
a good deal of extra electricity, but not quite enough to 
strike through the whole air between it and the earth. 
But it comes in the neighborhood of a tree containing 
sap-moisture which is a moderately good conductor. 
That helps bridge the distance to the earth. The elec¬ 
tricity strikes into the sap and follows it down. If the 
clond in small the charge may find roadway enough to 
get through quietly to the ground. If there are many 
trees, as in a forest, they will together supply sufficient 
roadway to the earth. Lightning seldom strikes trees in 
a forest, unless one is much higher than the rest and 
reaches up to a high clond. But if the tree stands alone 
and there is more electricity than can go along its sap 
easily, it will split and rend the tree in going through it. 
So it is never safe to go under a lone tree in a thunder¬ 
storm. If there was a small metal rod down through the 
tree the effect would be similar. If on outside of the tree, 
and large enough, all electricity would run down the rod. 
Note this especially: If the iron rod has a sharp point 
at the top, the electricity will spin off in a continuous 
little stream, so to speak, and unobserved. If the top is 
a round ball or a blunt end, a large lot of the electricity 
will jump from the cloud to it in a mass, with a report as 
loud as a pop-gun, a pistol, or a cannon, according to the 
amount, and if a very heavy charge, more than the rod 
* Scientific men will excuse our omission to speak of 
positive and negative electricity, etc., in this attempt to 
give a little popular instruction to non-scientific readers. 
can carry, it may melt it, and some of it may strike off to 
the moist wood of the tree, and perhaps rend that. 
Note this also. Anything between the charged cloud 
and the earth, that helps to shorten the distance, will 
help to a discharge of the electricity that might other¬ 
wise have floated by. A man’s moist body may be just 
enough to enable the electrical discharge to get from the 
clond to the earth through the resisting air. A gun- 
barrel will help a good deal more. Even an umbrella, 
with its metal rods and top, may be enough; so may a 
pitch-fork in his hand, or scythe on his shoulder. The 
electricity will take to his moist, poor conducting body 
in preference to the air, and if the discharge is large, 
the fluids of his body will only carry part of it and ha 
will be killed, or if but a small discharge, he may bo 
only temporarily stunned, and proper efforts may get the 
organs of the body into motion again, just as if they 
have been stopped by drowning. 
Note again, that glass, wax, feathers, etc., are non¬ 
conductors. If a person stands on any one of these, or 
is covered with one unless it is very thin, the electricity 
will not go through that line. Nervous people may feel 
perfectly safe in a thunder-storm if they can get upon a 
cake of wax, or thick plate of glass, with the clothing 
drawn close to the lower limbs, and not sit or stand too 
near a wall or chimney.—Moist air rising from a chimney 
or from fresh hay or grain in a barn, is a partial conduc¬ 
tor, that frequently helps form a channel from a cloud 
to the earth, and thus invites a lightning stroke. Hence 
the special utility of lightning rods in such cases. Any 
building having moist parts, or metals, supplies par¬ 
tial but attracting roadways from the clouds to the earth. 
To Drive Away Rats.— Mary Hadlem 
writes us that rats have so strong an aversion to the 
odor of peppermint; they will not enter rooms or bins 
where it prevails. She says of the peppermint plant: 
“;We place it in the oats, rye and corn, when they are 
brought in, and some goes under the pig-stye. Though 
we no longer have any rats, we continue to use the plant, 
for fear they may make us a visit.” If this is so, in 
the absence of the plant, probably a few drops of the 
oil of peppermint would answer the same purpose. 
