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METEOROLOGICAL. NOVEMBER THUNDERBOLTS. Thunderbolt Report to the Meteorological Section of the Franklin Institute at Its Monthly Meeting of December, by Prof. John Wise, Corresponding Secretary. [Reported for the Evening Bulletin.] On Monday, November 23d, 1874, at about 3 P.M., a thundergust passed over our city, The barometer had fallen nearly one inch in the previous twenty-four hours. The clouds were running fast and low from the west-southwest. A tornado sprang up some distance southwest of the city, accompanied by evolvements of lightning. As it passed over the city a thunderbolt was projected from it, which struck the roof of Dougherty's distillery storehouse, located in Front street, near Girard avenue. The discharge was preceded by a dash of hail and quickly followed by a copious dash of rain. The roof of the building is covered with tin. There is no lightning-rod on it, or on any other part of the buildings, of which there are a cluster. The bolt stuck the tin roof about twenty feet from the rain-spout corner of the building, and on a line running diagonally across the roof from that corner. The bolt perforated the tin and left a circular hole somewhat ragged around the edge. The hole is one and one-eighth inches in diameter, and immediately over a rafter timber in which a nail stump remains, and around which the wood is slightly singed. The chamber underneath the hole is plastered against the roof timbers. The plastering shows not the least disturbance - no mechanical effect whatever can be traced in the ceiling. A more conclusive proof of the protective nature of a metal roof against the danger and damage incident to thunderbolts could not be imagined. If a thunderbolt could be attracted from its course by conditions of ascending warm vapor-metal pipes out in the open air and proximate to the point of its impact- these were present, but produced no influence upon the projectile direction of the bolt. Like a ball from the muzzle of the gun it went forward in the direction of least resistance, as all thunderbolts have done, so far as their traces indicate. that I have examined within the past 25 years. Persons in the neighborhood of Dougherty's distillery noticed some of the attendant phenomena. Mr. John S. Naylor, of the People's Works, says: "Between 3 and 4 o'clock in the afternoon of Nov. 23d, 1874, my sight was directed towards Dougherty's distillery, the place which was struck. The flash and the report was simultaneous, and occupied merely a point of time-a moment as it were. The light were not streaked or zig-zag, or forked, as we occasionally see lightning, nor was it a series of flashed; nor were there and intillations or shooting of flame whatever; but the manifestation was one sudden illuminating flash, very intense and brilliant, of the yellow color of flame, faintly tinges with purple. The report accompanying the flame was not like thunder, crashing, reverberating or echoing, not was it a deep noise, It was a short, sharp, loud bang. The stroke occurred as the storm was breaking away, there being little rain at the time." Another observer saw fire and "smoke issuing from the rain water-spout." Another saw "pieces of the bolt falling into the area of the buildings." Had this bolt struck a wooden, gravel or slate roof, its mechanical effects would have been manifest in the rending of such materials as it has ever been upon examination, and in a number of instances that occurred in this city within the past five years of my observations. Now a word in regard to the inherent nature of a thunderbolt. Firstly, what is it? Electricity, says the "teacher"! What is electricity? A condition of matter, says the sophist! What is this "condition of matter"? It is the corpuscular action of molecules, says the zetetic philosopher! A motion pertaining to all matter - a motion inherent to all matter in the universal cosmogony, alike infinite and indestructible as it is universal. Strictly speaking, there. is no such thing as dead matter per se in nature. Organic dissolution is not death, much less can it be annihilation. The thunderbolt is molecular force! Whence comes this force? From the cloud! How does it get into the cloud, and what makes it come out of the cloud? Force being universal and indestructible, it can only be disturbed in its normal equilibrium, and be transmitted from one body to another, as it is is numberless well-defined instances, as in mechanics- by belt and pulley from one shaft to another. The bursting of a grindstone by what is termed centrifugal force is a good illustration of the action of a thunderbolt. Let us trace up the action of a thunderbolt! Water is lifted up from the sea by vaporization- a mode of force. It is held suspended in the interstices of the air as incisible mousture by force. The more atmosphere contains the clearer it is. Change the condition of this air as to its power of holding water in its interstices, and you release the power that lifted the water up from below, and holds it up, and this force will seek its more general magazine, and in accordance with the rapidity with which it is released. When, in the condensation of the "water-dust," clouds are formed slowly, the play of the unimprisoned force reveals itself in force by "low tension," and causes the play of "still lightning"; sometimes invisible, at others manifest in orange-colored flashed, from a cloud of plus condensation to a cloud of minus. When the condensation of the cloud vapor to aggregated drops of rain is sudden, an amount of force is suddenly evolved in the mode od a projected thunderbolt directly towards its prime reservoir, the earth; the sub-stratum of air presents an insufficient diaphragm to keep it from darting to the earth. In its descent it fires atmospheric matter that intercepts its course, and, when it comes in contact with the earth or any solid matter projecting from the earth that is not a good conducting medium, it produces mechanical action just in proportion as such obstructing matter in non-conductive or non-correlative to the motive energy of the bolt. The instant it impacts an extended metal surface it spreads out and is dissipated, not, however, without singing an equivalent surface of the metal. The lightning rod sophists claim for the efficiency of the rod—the various kinds of rods, from that of straw to those of all the grades and forms of metal—what Mesmer claimed for his "Tractors" used in his animal magnetism, and what the well-digger claims for his "divining Rod" in its pointing out the subterranean water course, and, it is safe to say, with equal integrity as to the efficiency of their respective claims. It is not the avoirdupois amount of metal that corellates the energy of the bolt; it is the amount of the surface that does it. All my 25 years of examination assert the fact. You might as well attempt the arrest of the ball fired from a columbiad with the point of a bayonet, as to attempt the arrest of a projected thunderbolt with a half or three-quarter inch diameter lightning rod. The sophisticated terms of "positive and negative electricity," of "vitreous and resinous electricity," of "inductive electricity," &e., if not defined in the stubborn logic of facts; or where it stands in a definition contrary to the facts made manifest by its positive action, are only calculated to confuse the mind of the student of science, and to mislead him in his deductions. There is a power behind the throne of all science, beyond the compass and comprehension of the human mind, for which we have no better word or name than motion. Even Tyndall's "environment" and Huxley's "automatism" fail to explain it, and it is past finding out. Molecular motion and organic motion can be only various in differentiated degree. They are convertible things. The thunderbolt is a play of released force in aggregated molecular form, and it obeys the common law of projectile forces in whatever condition they appear, and in whatever garb they present themselves. My observations authorize me to say that when metal roofs shall become the rule, instead of the exception, injury to our buildings and their contents by Jupiter's artillery will have passed away, as the apprehended danger has passed away before the light pf rational knowledge. The flood of light that has been shed upon us in the yet crude science of the persistence and corellation of forces is in itself sufficient to dispel the delusion of the efficiency of a bodkin to cope with a steam hammer. Imponderable elements, as we term those that are too fine for crude sensibilities to take material cognizance of, are not to be negated by homeopathic quantities of crude material. The finer the matter the more potent its action. That a thunderbolt is an electrical resultant from the sudden formation of a cloud and rain is evidenced in its never-failing attendant deposition of hail or rain. There may be a projection of thunderbolt with but little deposition of rain on the earth, and without any at all; but never without a rapid formation of cloud. I have watched storms from every possible point—from below, from above, from the sides, from within their vortical cauldrons, and I have been hoar-frosted in their midst in mid-summer, and I have always found electrical explosions to be concomitant with sudden changes of clean air into cloud and rain. Like from the individual grains of gun-powder, by ignition, a great amount of imprisoned force may be released, almost unperceived, and harmless as the dust that is blown against us in the street; but when it is concentrated in the death-dealing bombshell, to be let loose suddenly, it is far more destructive than the heaviest thunderbolt. The lightning stroke is suddenly released force—force transmitted from the cloud to the earth. To shield our houses from this oft-projected force we have, so far as experience teaches us, but one barrier, a metal superficies, not less than the superficial area of a dwelling affords—the great the superficies the greater the protection. It must not be forgotten that Franklin's theory of the lightning-rod was that it should prevent the projection of thunderbolts, by the rod tapping the electricity from the cloud as fast as it may be evolved, and thus prevent an electrical explosion. Now, modern lightning-rod doctors claim for the rod the virtue of catching the bolt and transmitting it to the ground in a harmless manner—a most preposterous assumption in the face of its continuous failure. This is ever met by the worn-out assertion that such a rod was defective—defective in the fact that none of them have superficies sufficient to instantly spread out the concentrated projective force by dispersion. Any area, to be fairly protected from the force of a thunderbolt, must present a surface of metal equal in dimensions to the portion to be shielded. Facts assert this, all theories to the contrary notwithstanding. Such is the avidity of the bolts for its metal corellative that it will demolish a stone tower that may intercept its passage between the cloud and the metal or the earth. This is the fourth recent case of metal roof protection in this city, to wit: White's building, corner of Twelfth and Chestnut; Wood's Museum; police station-house, in Buttonwood, below Eleventh, and Dougherty's distillery. THE LAST FLIGHT OF AN AERONAUT. Wise on "Thought" and Thoughts on Wise. Prof. Wise announces that he will deliver the closing lecture of the season at the Wagner Free Institute of Science, on Wednesday evening at 8 P.M. His subject is "Thought, its workings, etc." So wise in thought, Professor Wise, We long to know the thought in Wise. Wise thought be it, or otherwise, Who's thought like Wise is wise likewise.
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