The Trans. Tech. Soc. of the Pacific Coast, 2, 267 ; 1885, contains a paper by Fred. H. Jenssen on "Dynamite Catastrophes," in which he criticises adversely the theory advanced by L. J. Le Contef to account for their occurrence. Mr. Le Conte states that 90 per cent, of all the explosions on the Pacific Coast since 1879 occurred during violent desiccating north-wind storms, and that electricity has been the exciting cause in all these cases. Admitting the existence of a dry north wind at the time of the several explosions, it is a fact that the survivors of two of them give reasons for their occurrence which are at variance with Mr. Le Conte's theory.
The explosion at Stege on March 25, 1882, occurred during the manufacture of black powder, called Vulcan B. B. This powder is composed of sodium nitrate, sulphur and charcoal, which are mixed in a perfectly wet state. During this mixing process the superintendent called the foreman and told him that the mixture was not wet enough, and that he should put more water in the basin, as it had been demonstrated by experiment that where the mixture fell below a specified percentage of moisture it would ignite by the friction of the machinery. A few moments after the departure of the superintendent, and before the water was added, the explosion took place.
The explosion at the Giant Powder Works, January 21, 1883, was caused by sparks blown from a wheelbarrow of hot ashes into a box of dynamite.
As to Le Conte's second conclusion—that a dust explosion precedes that of the dynamite—Jenssen states that in the nitroglycerin department of the dynamite works there is no dust of an inflammable nature ; nevertheless a number of explosions have taken place in that department, especially during the first years of the manufacture of dynamite, but now are of rare occurrence. In all the dynamite explosions named, with the single exception of that at the Hercules Powder Works, September 29, 1883, no explosion started in the mixing house, and not one of them can be traced to a dust explosion.
In regard to the danger from lightning, it is admitted that a stroke of lightning will explode dynamite, but small sparks of electricity will not do so. The Swiss committee on the physical qualities of dynamite reported,* some sixteen years ago, that " thunderstorms and lightning involve no special danger to dynamite. As far as conclusions can be drawn from small experiments with heavy discharges of electricity, dynamite, unless well confined, will only burn if struck by lightning. But if well confined, and if the temperature produced by the lightning be high enough, an explosion may possibly take place."
Apropos of the danger of nitroglycerin being exploded by the heat of the sun, the author asserts that pure neutralized nitroglycerin or dynamite will stand 170° F. for some time before it decomposes. Long experience has demonstrated that dynamite cartridges in boxes can sustain a temperature of 128° F. for years. But when the dynamite without covering has been exposed for a considerable length of time (varying with the quality) to the sun's rays, on touching it with blue litmus strips the paper turns red.
On January 29, 1881, a man by the name of Lasker was killed in McKean County, Pa., by the explosion of a lot of nitroglycerin which was being thawed by the agent of Roberts & Co. for the purpose of " shooting " an oil well. Suit was brought to recover damages for the loss of Lasker, and the official report of the trial, which was continued from court to court, and which contains considerable expert testimony, is recently come to hand under the title Roberts vs. Lasker, in the Supreme Court of Pennsylvania, Eastern District, Paper Book of Plaintiff in Error.
From this we learn that nitroglycerin was used in the liquid state in torpedoes for " shooting " oil wells. The nitroglycerin torpedo consists of a tin shell from three to five inches in diameter, and from five to twenty feet in length, according to the quantity of glycerin which the well-owner desires exploded. All the shells are taken to the wells empty—the longer ones in sections, which are there put together as they are lowered into the well. The nitroglycerin is taken to the wells in square tin cans holding about six quarts each, and weighing when filled about twenty pounds each. This charge does not fill the cans completely, so water is poured in the space above to assist in the preservation of the nitroglycerin. After the tin shell is placed in the top of the well it is filled with nitroglycerin and tightly closed with a cover, in the middle of which is a percussion cap. When thus prepared the torpedo is lowered to the bottom of the well (a distance usually of about 1500 feet) by means of a wire. A perforated iron weight is then strung upon the wire, and, when the torpedo is properly placed, it is exploded by allowing the iron weight to drop from the surface of the ground and fall upon the cap.
The object of "shooting" the well is to remove the dense paraffins or other solids which obstruct the flow of the oil, and to shake the oil sandstone ; and nitroglycerin has been found most efficient for this purpose. The right to use this explosive is, however, secured to Roberts & Co. by letters-patent, and has proved a most profitable monopoly, their profits at the time of the trial being fixed at three thousand dollars a day. Naturally their rights were infringed or evaded in many cases, and a class of men known as "moonlighters" sprung up in the oil regions, who exploded torpedoes in the oil wells at night. Others, however, simply placed a large torpedo in the well, and then employed Roberts & Co. to explode a small torpedo above it. The torpedo thus surreptitiously inserted in the well is known as a "setter," and it is believed by those who practise this that they successfully evade the Roberts patent.
As the driving of wells is carried on at all seasons, it frequently happens that the nitroglycerin comes on the ground in a frozen state. That was the state of the nitroglycerin in this case, and it was sought to thaw it by placing the cans (seven of them) in an oil barrel filled with water and passing steam through the water. Four of the cans were placed at the bottom, and the remaining three on top of these. The corks were out of the cans, so that the explosive was surrounded by water. The oil barrel rested on trodden-down snow, and the steam was brought seventy-five feet through a rubber hose stretched over the snow. There were fifty pounds' pressure in the boiler, and the throttle was turned about one-fourth. It seems undetermined whether there was or was not an iron nozzle to the hose, but the end of the hose reached to within four inches of the bottom of the barrel. The hose remained in the barrel for about one-half hour, when it was taken out, as the water was thought warm enough. After another half hour it was put in again, and had been in but a short time when the agent walked to the barrel and found the water perfectly quiet, and so hot he could but just bear his hand in it (about 115°-120° F.). He then turned away, and had gone but about fifty feet, and had been away but about twenty seconds, when the explosion occurred. The agent was uninjured, but Lasker, who was in the engine-house, about six feet off, was killed. The defendant sought to show that a "setter" had been put in the well, and that the nitroglycerin for it had been thawed during the night in this same barrel, and that some of the liquid had been spilled in the barrel, but the court refused to admit the testimony. The plaintiff sought to show that the explosion was induced by the agitation set up in the barrel by the escaping steam, or by the energy developed by the steam impinging on the cans, but the real cause was left in doubt.
In the course of his testimony W. B. Roberts stated that he had made nitroglycerin since August, 1856, and that during that time he had made about one million pounds and handled one and a half million pounds. He first became acquainted with it after the explosion in Greenwich street. New York. The remainder of this had been buried by the authorities near Eighty-third street. Dr. Roberts went there, dug it up, and got about one hundred pounds, which he sent to Titusville, and used in the oil wells. The nitroglycerin now used is transported about the country, over the roughest roads, in spring wagons, the boxes being partitioned into squares the size of the cans, and upholstered with leather on the sides and bottom. The empty cans are destroyed by piling them on a brush heap, laying a train of nitroglycerin under it and setting fire to the whole. When explosion takes place at one point it is immediately communicated to the whole. No method of cleansing has yet been found which is effectual.
As giving some idea of the extent of the nitroglycerin industry in this country, we note that Mr. W. N. Hill stated in his testimony that, as chemist to the Repauno Chemical Company, he was, at the time (1882), making from fifty to one hundred thousand pounds of nitroglycerin a month. Sometimes he had made as many as ten runs, of six to seven hundred pounds each, at one time.
In the course of the trial various books were offered in evidence, and the court ruled that they might be read to the court to explain the scientific names and terms used, but not to the jury. The rule seemed to be that books written upon inductive sciences were not admissible, while those on the exact sciences could be offered. He believed the science of chemistry an exact science, and not an inductive one in a philosophical sense of the term, but the scientific knowledge of nitroglycerin might not be so exact as would authorize the reading of authorities in evidence to the jury. Some of these books might be evidence—for example, those which treated of the whole system of chemistry. He had grave doubts as to the articles written in the chemical journals being evidence, but they could be read to the court as law-books.
W. Poetsch (Dingl. polyt. J. 255, 216) suggests "Recovering the Waste Acids from Nitroglycerol Works " by the following method On heating the waste acids, consisting of sulphuric and nitric acids and organic nitro-compounds, at 105°, decomposition of the nitrocompounds ensues, oxidation to carbon dioxide taking place at the expense of the nitric acid which is present. During the reaction enough heat is liberated to volatilize the remaining portion of undecomposed nitric acid and the lower oxides of nitrogen produced, pure sulphuric acid being left in the residue. The author uses- a closed vessel of stone or lead, having a perforated bottom 50 cm. above the bottom. The upper space is filled with stones or broken stoneware, and heated by hot air. The waste acid is introdliced.in a thin stream through a funnel fitted into the cover of the vessel, and, passing over the hot stones, is decomposed. The nitrogenous vapors are led through an earthenware pipe to a cooling worm, and collected in Wolff's bottles, air being introduced to oxidize the gases to nitric acid. The denitrated sulphuric acid flows through the perforated bottom, and is run into receiving tanks. (Abstr. Jour. Chem. Soc. May, 1885, p. 619.)
After more than seven years of investigation and experiment, the English royal commission appointed to inquire into accidents in mines has presented its final report, which was issued April 10, 1886, in the form of a blue-book of one hundred and ten pages. The delay is accounted for by the long and difficult quest on which the commissioners were sent. They were to report not only on the causes of mining accidents, but also on the "possible means of preventing their recurrence, or limiting their disastrous consequences." Not much is recommended in the way of mere legislative changes, but the scientific recommendations are most interesting and important. For example: With reference to the difficult question of the best method of firing shots in mines, they state that "electrical exploding appliances present very important advantages from the point of view of safety over any kind of fuse which has to be ignited by the application of flame to its exposed extremity, as the firing of shots by their means is not only accomplished out of contact with air, but is also under most complete control up to the moment of firing. Their simplicity and certainty of action have been much increased of late years, while their cost has been greatly reduced, and but little instruction is now needed to ensure their efficient employment by persons of average intelligence. The use of electrical arrangements for firing shots in mines, where the employment of powder for blasting is inadmissible, should be encouraged as much as possible."
Again, they state that "it has been shown that mines which have hitherto been considered free from fire-damp may have the air which passes through them vitiated to an extent corresponding to about two per cent, of its volume of marsh gas. The air in many such mines may probably never be entirely free from explosive gas ; at all events, in the neighborhood of freshly cut faces of coal and in the return air-ways. It has been demonstrated in our experiments that when the atmosphere contains five to five and one-half per cent, of marsh gas, it becomes highly explosive. We have even obtained explosions which, though less violent, might be, nevertheless, destructive of life if they occurred on the large scale possible in a mine, when the air contained only four per cent, of marsh gas. It will thus be seen that air which would appear free from gas if tested in the ordinary way, may become, by the addition of only about two per cent, of marsh gas, capable of propagating flame and causing destruction, while the addition of about three per cent, converts it into a highly explosive mixture. Air which would appear quite free from gas if examined by a lamp flame, may become explosive when laden with fine, dry coal-dust. Appliances now exist by which very small proportions of marsh gas in air may be readily detected, and which can be used for examining the atmosphere of a mine. With Liveing's indicator, gas present in the air can be estimated with sufficient accuracy for all practical purposes, even when the proportion is as low as one-quarter per cent."
The suggestion, first due to Mr. Galloway, that coal dust alone suspended in air might cause an explosion, is considered, and an account is given of some carefully devised experiments which rather tend to confirm this conclusion. The commissioners discuss with some detail the means of removing this dust, and devote a large section of the report to the question of the conditions under which blasting can be done in safety. Considerable space is devoted to safety lamps, and it is pointed out how great an influence the velocity of the air-currents in the air-passages of a mine has on the safety of a lamp. The commissioners are of the opinion that the older Davy, Clauny, or even Stephenson lamps, have in a great measure lost their value in consequence of the draughts of air from the free ventilation. A current of air of eight hundred feet per minute in an impure atmosphere may, in spite of the wire gauze, effect an explosion in any one of them. The electric lamp is perhaps the chief hope of the miner, though it does not, like the safety lamp, indicate the presence of gas. A rigid daily inspection is recommended. {Science, 7, 389, 459; 1886.)
Any difference between the calculated and observed pressures must be attributed to the action of the walls of the explosion vessel, since Mallard and Chatelier have shown that carbon dioxide and water do not dissociate below 1800° and 2500° respectively in explosions.
Although explosions of coal gas with air are by no means infrequent, the compiler has found considerable difficulty in producing them at will on a laboratory scale by simply mixing air and gas. Acting on these suggestions of the part played by dust, he has placed a small quantity of lycopodium in the stout glass cylinders used for the experiments. Gas was then allowed to flow in, the vessel covered and shaken. Then on applying a flame there was invariably a smart explosion.
G. Schelgel, in treating of the "Combustion of Hydrocarbons and their Oxides and Chlorides with Mixtures of Chlorine and Oxygen " (Annalen, 226, 133-174), says it has been shown by Botsch (Abstr. 1882, 456) that in the explosion of a mixture of hydrogen, oxygen and chlorine, water is formed only when the chlorine is present in amount insufficient to unite with the whole of the hydrogen. This result is important, inasmuch as it does not agree with the generally accepted rule that when several substances react simultaneously on one another, those reactions always occur in which the greatest amount of heat is developed. The author has extended these researches to the products of the explosion of mixtures of chlorine and oxygen with gaseous organic compounds. Experiments were made with excess both of chlorine and oxygen, with an excess of oxygen and an amount of chlorine insufficient to unite with all the hydrogen present, and finally with an excess of chlorine, but with an amount of chlorine insufficient to convert the whole of the carbon into carbon dioxide. The organic substances employed were methane, ethane, propane, butane, methyl ether, methyl chloride, ethyl chloride, acetylene and carbon monoxide. No results could be obtained with ethylene, as it unites with chlorine in the dark, and so prevents the formation of a uniform mixture for explosion. The following are the conclusions drawn from these experiments : 1. If a hydrocarbon be mixed with excess of chlorine and excess of oxygen, and the mixture exploded by the spark, the whole of the carbon is converted into carbon dioxide, and all the hydrogen into hydrochloric acid. Hydrogen does not unite with oxygen, nor chlorine with carbon. 2. If excess of oxygen be employed together with an amount of chlorine insufficient to combine with all the hydrogen present, the remainder of the hydrogen unites with the oxygen. 3. If with excess of chlorine the amount of oxygen is insufficient to convert all the carbon into carbon dioxide, there is then also formed carbon monoxide. The proportion of this latter increasing with the deficiency of oxygen. 4. If neither chlorine nor oxygen is present in sufficient quantity for complete combustion, carbon is separated. 5. The organic chlorides and oxides experimented with behaved in like manner to the hydrocarbons. (Abstr. Jour. Chem Soc. March, 1885, p. 214.)
F. Bellamy has studied the "Action of Some Metals on Mixtures of Acetylene and Air" (Compt. Rend. 100, 1460-1461; 1885), with the following results : When a spiral of platinum or silver wire, heated just to incipient redness, is brought into a mixture of acetylene and air issuing from a modified Bunsen burner made of glass, the gaseous mixture at once detonates and inflames, but the spiral does not become incandescent. If, however, a copper spiral is treated in the same way, the wire becomes brilliantly incandescent, and eventually ignites the gaseous mixture. A spiral of iron wire behaves in a similar manner, but the incandescence is more difficult to obtain if the spiral is too hot the gaseous mixture is at once ignited ; if too cold, the wire remains non-luminous. Copper or iron wire does not become incandescent in a mixture of air and hydrogen.
Colonel Samuel Wetherill, Jr., has privately communicated to us an account of an explosion of metallic zinc. While engaged in 1854 in the manufacture of this metal, he devised a plan for utilizing the "blue powder," which is the finely divided metallic zinc deposited in the prolongation of the condenser. The process consisted in swedging the powder into blocks and placing these blocks one above another in a furnace, where they melted down and were run into spelter. The workman in charge proposed to facilitate the process by feeding the "powder" directly into the hot furnace and ramming it down with a bar. On trying this the first shovelful exploded, and with such violence that the man was blown from the top of the furnace and the blade of the shovel driven into the roof of the building.
In this connection we may state that with the "blue powder" furnished us from the Bethlehem Works we have easily obtained Schwarz's explosive reaction* with sulphur, though we were unable to get it with the powdered zinc of commerce, owing probably to its being superficially corroded.
We are indebted to Sir Frederick Abel for a copy of his address on "Accidental Explosions Produced by Non-Explosive Liquids," which was delivered before the Royal Institution of Great Britain, March 13, 1883, and which deals with the explosions produced by the petroleum oils. The lecturer cites numerous instances of explosions from this cause which have occurred both on land and at sea, details the attending circumstances and seeks to explain the cause. The most interesting to us are those on the Coquimbo, Cockatrice, Triumph and Doterel, which the lecturer now believes to have been caused by the petroleum spirits used in the xerotine siccative.
In the Proc. Am. Asso. Ad. Science, 33, 130; 1885, Charles E. Munroe proposes to use an electric motor and gun-cotton for illustrating experimentally the " Conversion of Mechanical Energy into Heat." For this purpose a Griscom electric motor is clamped to the base of a retort stand with its axis of revolution vertical, while a brass disk to which a flat cork is cemented is clamped on the end of the shaft. A shallow cavity is made in the cork, the bottom of a test tube is placed in the cavity, and the tube clamped in place. Guncotton is now rammed into the tube, the vessel corked, and the motor set in motion. With four Grove cells the friction of the cork on the tube generates sufficient heat, in half a minute, to fire the gun-cotton and blow the cork from the tube. With this apparatus the difference in the points of ignition of gun-cotton and gunpowder, and of gunpowder grains of different sizes and densities, besides many other experiments depending upon the generation of heat through friction, may be easily and simply shown.
In the study of the "Action of Primary Alcoholic Iodides on Silver Fulminate," by G. Calmels (Compt. Rend. 99, 794-797), 25 grams of dried silver fulminate were heated with 25 grams of methyl iodide and 40 grams of ether in a sealed tube at 50° for twenty-four hours. The products were silver iodide, methyl carbylamine and ?-nitroethylene. Ethyl iodide and the higher primary iodoparaffins react in a precisely similar manner.
CNAg : CAgNO2 + 2MeI =2AgI + CNMe + CH2 : CH2NO2
In this reaction silver fulminate is split up into two parts. In order, if possible, to obtain the intermediate compounds CNMe : CNMeNO2, CNEt : CNEtNO2 100 grams of methyl iodide mixed with 50 grams of ether were allowed to act on 50 grams of the dried fulminate at the ordinary temperature for four or five days, but the only products obtained were a-nitroethylene and methylcarbylamine. Ethyl iodide and its higher homologues behave in the same way.
The nitro-derivatives of the ethylene series are characterized by their power of existing in two modifications, the a-derivatives forming colorless liquids soluble in ether and chloroform, whilst the ?-derivatives are yellow, resinous solids insoluble in the same solvents. From their chemical behavior, it would seem that the former are the true nitro-derivatives, whilst the latter are oximido-derivatives.
A. Ehrenberg states {Jour. prak. Chem. 30, 38-68; 1884) that Carstanjen and he have shown (Abstr. Jour. Chem. Soc. 816, 1882) that when mercury fulminate is decomposed with aqueous hydrochloric acid it yields its nitrogen as hydroxylamine hydrochloride. A further examination of this reaction has proved that both carbon monoxide and carbon dioxide are formed. The quantity of these compounds produced is but small, more especially when the decomposition is effected in the absence of air ; and it appears that they owe their origin to the decomposition of formic acid, which the author has shown is produced by the action of aqueous hydrochloric acid on mercury fulminate.