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altitude. The colours so vividly displayed would appear to be almost conclusive that the action and effect, if not the seat or origin thereof, is in the vapour plane of the atmosphere. And that like the rainbow, halos, sunsets, and colours of the clouds, so the vivid hues, tints, and iridescence of the aurora are owing to the presence of vapour, however attenuated it might be.

Assuming, therefore, that the aurora is moderately elevated, and more properly belonging to the upper than to the lower regions, we may suppose then that the wind might have some slight perceptible effect upon the needle; since the wind is the current from the quarter of high pressure, and which is not solely the result of the action of the lower stratum, but the sum of the aggregate pressure of the mass of the atmosphere. Hence, as the barometer indicates the state of the superincumbent mass, and the wind being the result thereof, the needle may be acted upon by the distant area from which the wind proceeds. Thus, an easterly wind acting on the needle, is assumed to be from some change or condition in the eastern area, in the upper or lower plane; just as much as that the distant aurora affects the needle at Greenwich. If the aurora at a moderate height affects the needle, what prevents any electric state or condition, at the same height and over the same extent of area, affecting the needle in a degree likewise?

The well-recorded fact of Recurring Monthly Periods of maximum and minimum states of the magnetic needle, proclaims its varying condition, and allows of

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the fair induction that electricity is capable of being transferred. The transfer of electricity is analogous to its compeer, heat. The diurnal periods bespeak a gentle transfer, and the maximum in the one place is a consequence of a transfer from some other area, which consequently has a minimum. The one cannot have more unless the other has less, is the fundamental law and recognized principle.

As heat extends over large areas, and its transfer is upon a considerable scale, so likewise is that of electricity. One atmospheric area loses, and another atmospheric area receives the transfer. Professor Faraday, the most celebrated authority on magnetism, says: "The condition of the two hemispheres may be conceived by supposing an annual undulation (transfer?) of the force to and fro between them, during which, though neither the character nor the general disposition of the power be altered, there is in our winter a concentration and increase of intensity in the northern parts, coincident with a diffused and diminished intensity in the south, and in summer the reverse."

The subjoined account of the mean monthly variation of the declination needle, at two places of the same degrees of latitude, but in opposite hemispheres, presents the evidence of the influence of the seasons upon the magnetic needle. How equable and regular in both, although the antipodes of each other. What an amazing uniformity and conformity to order and recurring monthly periods exists throughout the vast aërial ocean!

That electrical phenomena depend on some infinitely subtle and powerful agency pervading the material world, is, in the present state of natural knowledge, almost certain. That this agency, although differing essentially from any form of matter of which we have the least cognizance, is itself material, is also highly probable and generally admitted; therefore, we have no difficulty of admitting of the transfer of a given quantity of electricity from one area to another, and from one hemisphere to another, any more than that we in our experiments can transfer the electricity from one Leyden jar to another jar, either in part or altogether. And as we cannot accumulate any charge of electricity without taking it from some other part, so, no mass of clouds can be charged with electricity, without receiving it from some other part of the atmosphere. And thus electricity strictly comports itself with its congener and ally, heat. Both have the property of transfer.

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Electricity is fairly assumed, and almost proved, to be absolutely transferred from one hemisphere to another. The action is positively apparent and real, and can the agent be absent? The material quality, be it ever so refined, is transferred in such a definite amount, that what the one loses the other gains. Such is as obvious as any ledger or mercantile account, or that a balance the most delicate can declare. It is here again weighed by measure. It is true we cannot weigh the light, but we can measure its beams in the rainbow, which Milton calls "the triple-coloured bow." It is very remarkable that there should be such a strict and perfect mathematical and chemical coincidence between the measures assigned to the colours of the rainbow and their associated gases.

Thus the violet portion of the bow is double the volume, nearly, of the red. The red rays are heating rays, and analogous to the oxygen end or pole of the electric battery. The violet rays are the chemical or actinic rays; they associate or agree with the hydrogen end of the voltaic battery; and the hydrogen gas is the double combining volume of oxygen. Hence a perfect analogy exists between the volumes of the two colours of the bow, and the gases with which those colours are associated in quality, nature, and action. What a perfect concordance reigns throughout nature!

The poets have ever taken it

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for a fairy vision of some gay creature that in the colours of the rainbow live; and Campbell says

"When Science from creation's face

Enchantment's veil withdraws,

What lovely visions yield their place
To cold material laws."

Which, however poetically beautiful, is a most unjust rebuke, inasmuch as truth exceeds fiction.

If electricity is proved to be transferred from one hemisphere to another, consequently from one area to another, then we cannot refuse to assign to heat the same range from hemisphere to hemisphere which electricity possesses. Since we have already demonstrated the transfer of heat from area to area to constitute the leading principle of atmospheric action, then the three aërial agents, infinitely more subtle than the air itself, make to themselves wings and fly away to distant realms. Heat, light, and electricity, are the affections of nature, kindred and congenial spirits, children of the sun, and are as the three graces which constitute the life, the charm, and spirit of the whole material world. The summer gains but what the winter loses, by a gentle transfer of all the three, and universal good prevails where order and obedience reign.

The intensity and quantity of atmospheric electricity are very well represented by lightning and the aurora.

The heated tropics present large masses or plates of gigantic clouds, highly charged with electricity, (which rushes down in terrific lightning, melting or fusing the