408 Quetelet on the Electricity of the Air. 



same. Theoretical and practical results will, it is true, never 

 entirely correspond, but they should be much more nearly alike 

 than they ever yet have been. Whatever improvements have 

 at any time been effected in the economy of fuel, have originated 

 in a careful and rational application of the physical laws which 

 relate to combustion, and of those on which the doctrine of heat 

 is founded. Apparent trifles, such, for instance, as insulation 

 of the boiler by non-conductors of heat, accommodation of the 

 draught to the nature and quantity of the fuel, etc., have been 

 the cause of very important saving on the item of fuel; and 

 whatever good shall be hereafter effected in the same direction, 

 will be due to a like judicious application of the practical know- 

 ledge with which experience and research shall have furnished us. 



QUETELET ON THE ELECTRICITY OF THE AIR. 



In his important work, Bur la Physique du Globe, M. Quetelet 

 gives a voluminous account of the electrical observations made 

 under his superintendence at Brussels, and devotes one section 

 to an explanation of the distribution of the electricity of the 

 air, which cannot fail to interest our readers, and which we 

 therefore present to them in a condensed form. 



M. Quetelet remarks, that were it not for the existence of 

 other bodies in celestial space, the terrestrial atmosphere would 

 scarcely experience any electrical changes. He further tells us 

 that the sun must be regarded as the chief exciting and dis- 

 turbing cause. He regards our atmosphere as divided into 

 two layers ; the upper one, n.p., " nearly immoveable in all its 

 parts, the lower one, p.n., constantly traversed and stirred up 

 by winds." The upper layer he considers is also divided into 

 two portions : the one negative, n., equilibrates the positive 

 electricity, v., of the sun, and of the surrounding space ;* and 

 the other positive, p., acts through the lower stratum of air, and 

 equilibrates the negative electricity of the earth, n. The posi- 

 tive and negative electricities of the upper regions of the atmo- 

 sphere are kept apart by the extreme dryness which must prevail 



t M. Quetelet adds in a note, " If it is objected that the electricity of the sun 

 traverses the void without resistance, and that its fluid ought to unite with the 

 fluid of the opposite nature which we suppose to exist in the exterior layer of the 

 atmosphere, we might without difficulty admit this hypothesis, and our explana- 

 tion would be simplified. There would, in fact, remain only the positive elec- 

 tricity below the superior envelope of our atmosphere, which would paralyze on 

 one side the negative electricity of the sun, and on the other would act through 

 the inferior envelope and paralyze the negative electricity on the surface of the 

 globe. We must then admit that the electricity of the sun and the earth are of 

 the same kind. 



