588 PHILOSOPHICAL TRANSACTIONS. [anNO 1755. 



air, while the exterior air remains condensed. Secondly, that there is not any 

 allowance made for the weight of the included air. Thirdly, the constituent 

 particles of water are but very little, if at all altered in their specific gravity. 

 Fourthly, that this thin vesicle can never be a sufficient boundary between the 

 exterior condensed air and the interior air, so exceedinglv rarefied. 



Rejecting these popular opinions, as to the cause of the ascent of vapours and 

 exhalations, Mr. E. observes that it now remains to inquire, by what means this 

 may be done ; since neither impulse, rarefaction of the air, nor any formation of 

 their parts by expansion, seem sufficient for the purpose. There appears to him 

 but one way of altering the specific gravity of the particles of vapour and exha- 

 lation, to render them lighter than air, which is by adding to each particle a suf- 

 ficient quantity of some fluid, whose elasticity and rarity are exceedingly greater 

 than that of the air. That the fluid or fire of electricity is such, will be easily 

 granted; but how far it is adapted to this purpose, we must inquire from expe- 

 riments. For the purpose is great; no less than all vegetation and animal life 

 depending on the ascent and descent of vapour and exhalation. 



Mr. E. says he has made some experiments, by which it appears that all fumes 

 arising from fire, whether blazing or otherwise, and all steams rising from boiling 

 or warm waters, and from all other fluids, and the breath of man, and of all 

 other animals, and all the effluvia thrown oft' by perspiration, are strongly elec- 

 trified. But he now only mentions a few. First, that desultory motion, by 

 which it flies ofl^ from an electrified body to any number of non-electrics, which 

 are brought within the sphere of its activity and affection, till it be equally dif- 

 fused through all. Secondly, that the sphere of its activity is increased by heat. 

 Thirdly, that this fire does not mix with air. Fourthly, that it intimately per- 

 vades water, and many other bodies, covering their superficies to a certain dis- 

 tance; which distance is not in proportion to the bulk, of the body electrified, 

 but in proportion to the state of activity of the electrical fluid. Fifthly, this 

 electrical fluid readily joins with any fire which fumes, or rather with the blaze 

 or fumes of, any fire; but will not mix or fly oflT with the fire of red-hot iron, 

 or any other metal, which does not fume. 



Now, to show that this electrical fire or fluid is the principal cause of the as- 

 cent of vapour and exhalation, we need only prove that it attends all vapour and 

 exhalation, and that in such quantity, as is necessary to render them specifically 

 lighter than the lower part of the atmosphere. He does not undertake to deter- 

 mine, by what cause vapour and exhalation are detached from their masses, 

 whether by the solar or culinary fire, or by the vibrations of the electrical fluid 

 rendered more active by those fires; though he thinks the latter. But it is evi- 

 dent, that they are emitted in exceedingly minute distinct particles, and that 

 these particles must pass through that electrical fluid; which surrounds the sur- 



