and pour down electric rain. The electricity of the clouds, and of the rain, continues to increase, till that part of the autumn, in which the last fruits are gathered. It actuates and animates vegetation. It is the agent that collects the vapours, forms the clouds, and is then employed to dissipate them in rain. This great principle, as I have already said, is neither generated nor destroyed; it is every where, and always present, though latent and unobserved, and is in motion by day and by night. The supposition of an ingenious writer is, indeed, by no means improbable, that the vegetating power which is operating during the whole year in ever-greens, may arise from these trees having more resin in their composition, than those whose leaves fall in autumn, by which they are enabled to attract and retain those juices, which give them their continual verdure, and supply in some degree the absence of solar heat. And this is confirmed, by the strong electric power possessed by their leaves. The same writer thinks, the fluid collected in our electrical experiments, is only those solar rays, that have been dispersed in, and are arrested by the earth; an idea, which is strongly corroborated by the observations made on atmospherical electricity, and by the deductions which have been been made from the relative affinities of fire, light, and heat. • The electric fluid is essentially connected with the human frame, and is continually exerting its influence upon it. Hence we may perhaps find, that what we call sensibility of nerves, and many other diseases, which are known only by name, are owing to the bodies being possessed of too large, or too small a quantity of this subtile fluid, which is perhaps the vehicle of all our feelings. Thus, says Brydone, in his Animated Observations on Scicily, in damp and hazy weather, when this spirit seems to be blunted and absorbed by the humidity; when its activity is lost, and little or none of it can be collected, we ever find our spirits more languid, and our sensibility less acute: but, in the Sirocco wind at Naples, when the air seems totally deprived of it, the whole system is unstrung, and the nerves seem to lose both their tension and elasticity, till the north, or west wind, awakens the activity of this animating power, which soon restores the tone, and enlivens all nature. This vivifying fluid does in fact communicate itself to the human body, and not only by the pores, but also by the lungs, which Bertho VOL. II. D lon lon looks upon as the secretory organ of aerial electricity: and, as we also conjectured in a former letter, when treating of airs, and of the highly phlogisticated state of the blood, which is attenuated and rendered florid, by apparently nothing else than the action of the lungs, and the influence of the dephlogisticated fluid, which keeps them in motion. The effects, indeed, of electricity on the general system, is wonderful; and consequently on the vital frame, and on all animal functions; such as muscular motion, respiration, digestion, and the various secretions. But, respiration is the powerful act, by which man imbibes the greatest quantity of this fluid : for it has been calculated, that the motion of respiration is repeated 28,800 times every day, and that the lungs receive in that space of time, one million, one hundred and fifty-two thousand cubic inches of air. Bertholon, moreover, proves the influence of the electrical fluid upon vegetables, by their analogy with animals, by the nature of the fluid itself, which must pervade them; by the distinctive characters of the electrical phænomena, such as lightning, thunder, rains, northern lights, water-spouts, &c. by the influence even of snow, hail, and mists on the vegetable kingdoms; by the quantity of water, which the atmosphere receives from seas, rivers, lands, lands, animals, and plants; and by the nature of that water, which, as it is an excellent conductor, falls from the clouds, impregnated with the electrical fluid, and discharges it upon the earth. The force of vegetation, says he, is principally owing to the electrical fluid, with which this rain water is impregnated, and not to those aerial nitrous vapours, which have hitherto been considered by many, as its principal cause. Those years, in which thunder storms have announced the greatest measure, and activity of the electrical fluid, have been most distinguished by the speedy maturity, and by the abundance of fruits and vegetables. And this may be readily proved, by depriving water of the electrical fluid, which it has imbibed in the atmosphere, when it will be found to be deprived of the greatest part of its nutritive power, and of its influence on plants. Thus, perhaps, of all the causes assigned for the wonderful vegetation that is observed on Ætna, there is none that contributes so much towards it, as the constant electrical state of the air. The vapour of volcanos is highly electrical. Penetrating the vegetables, it drives the juices through the smaller vessels with increased ease and celerity. It is, in short, the soul that quickens D2 quickens them, as it does every other organized body in nature; and there is little doubt but that the fertility of seasons depends as much on this quality in the air, as either on its heat, or on its moisture. * And perhaps we may be allowed to venture still farther. Pass the charge of a large jar or battery, from the head to the back of an animal; this, if sufficiently strong, will kill it. After its death, make the discharge in the same manner, and the fluid will pass visibly over the body, and not through it; evincing, that the power, or medium, which transmitted the shock through the animal, is lost with its life. But, what is this medium? I fear it is not yet well understood. For it is 'said, that all parts of the animal frame, while they preserve their juices, give a free passage to the electric fluid: but, if these parts be dried, the passage of the electric fluid is stopped. What is here meant, are the solids, or those parts which tend to solidity. The blood, the saliva, the serum, &c. being fluids, give a free passage to the electric fluid. But, the arteries, the veins, the intestines, the bones, the nerves, &c. after they have become dry, cannot be employed either in the charging, or in the discharging of a phial. + : * Brydone. † Steighlehner.. The |