U. S. NAVAL INSTITUTE, ANNAPOLIS, MD.

NOTES ON THE LITERATURE OF EXPLOSIVES.* BY CHARLES E. MUNROE.

No. XXVII.

The "19th Annual Report of H. M. Inspector of Explosives. for the year 1894 states that blasting amberite, cordite, collodion cotton, Westfalite and Von Forster's powder were added to the list of authorized explosives; securite, compressed securite and Denaby powder were dropped from the list, as their manufacture was given up during the year. Nitro paper, plastomentite, electronite, granulite, normal smokeless powder, one variety of Rosslyn smokeless powder, emerald powder, carbonite, smokeless powder and Coopal's powder successfully passed Dr. Dupré's tests and were favorably reported on. Britianite passed the preliminary tests. Schnebelite, three varieties of Rosslyn smokeless powder and one of electronite failed and were rejected.

Schnebelite offers another example of the eventual rejection of a chlorate powder, the powder having passed successfully the preliminary trials as reported December 13th, 1893. During the succeeding year it was submitted to a more prolonged and searching examination, in the course of which, like other chlorate mixtures before tested, it developed certain features pointing to danger. Not only did it show a marked increase in sensibility to percussion and friction, but an appreciable portion of the chlorate became reduced to chloride.

*As it is proposed to continue these notes from time to time, authors, publishers, and manufacturers will do the writer a favor by sending him copies of their papers, publications or trade circulars. Address, Columbian

The sample of electronite which failed showed the peculiar behavior of ammonium salts. This sample consisted of amberite No. 1 (nitro-cellulose, nitro-glycerin, paraffin and shellac) mixed with a considerable proportion of ammonium carbonate, and it suffered serious decomposition, even when kept at ordinary temperature.

An invention having for its object the prevention of the mercury fulminate from escaping from detonators, and which consists either in covering the fulminate with a solid disk of celluloid which fits tightly in the case, or in coating the fulminate with collodion, was reported upon favorably, as was an invention consisting in the introduction of glass tubes filled with a strong solution of ammonia into gunpowder blasting cartridges, with a view to diminishing the effect of the flame produced on firing them.

With the admission of collodion cotton to the "authorized list," a revision in the definition of terms has been made. Hence officially collodion cotton consists "of thoroughly purified nitrocotton (a) of which not less than 15 per cent. is soluble in etheralcohol, and (b) which contains not more than 12.3 per cent. of nitrogen," while gun-cotton consists of thoroughly purified nitro-cotton (a) of which not more than 15 per cent. is soluble in ether-alcohol, or (b) which contains more than 12.3 per cent. of nitrogen; and with or without carbonate of calcium." The term nitro-cotton is to be "substituted for nitro-cellulose in the definitions of ballistite, gelatine dynamite, blasting gelatine," etc. It is to be regretted that strictly scientific terms were not adopted at the outset, since much confusion of ideas has resulted from the official classification.

Another new feature in designation is in the use of the terms "percussion cap " and " detonator," as a consequence of the two similar accidents which occurred in the drumming of caps in the Royal Laboratory, Woolwich, on July 24th and August 20th. The drum in which the caps are cleaned is of sheet iron, 2 feet in diameter by 7 inches wide, and at the time of the explosion it was charged with 80,000 caps for the 0.303-in. ball cordite ammunition, each containing 0.4 grain of a composition consisting of mercury fulminate, 6 parts; potassium chlorate, 14 parts; antimony sulphide, 18 parts; powder, mealed, I part; sulphur, ground,

which is turned by hand, had been revolving some three or four minutes when the explosion took place. The explosion partly blew out one side of the drum and scorched the rope mantlet which surrounds it to a height of 6 feet 6 inches, doing no further damage. About 20,000 caps were recovered unexploded. Experiments made to determine the liability of these caps to explode en masse showed that this would not occur unless the caps were raised to a high temperature or mixed with loose composition, but as an additional precaution the dividing line between percussion caps and detonators has been raised above that fixed in Annual Report, 1885, pp. 69, 117, and 1890, p. 53, so that now it is ordered that "a percussion cap to be one containing a charge not exceeding 0.5 grain of composition, or 0.6 grain of composition when the quantity of fulminate of mercury does not exceed one-fourth of such composition; in any other case the cap will rank as a detonator."

In order to identify individual cartridges of explosives, especially when stolen, the German and Belgium governments have recently required that each be marked and numbered. The ingenious method devised by Germany, through which is indicated the factory of origin, date of manufacture, and case in which packed, is described in this report at length with diagrams. After consultation with English manufacturers it was decided that in view of the expense and inconvenience the system entails, and the facility with which the elaborate and costly precautions could apparently be defeated by evil-disposed persons, there was not sufficient warrant for directing the compulsory adoption of such a system.

The comments of Dr. Dupré on an accident at Gover Farm, Abergele, during the burning of rubbish in a grate, illustrates how numerous the causes are which may possibly give rise to explosions. He says: "I have carefully read the further information given, and have also inquired as to what kind of material farmers use that might possibly cause an explosion. I find that some kinds of manures are used consisting of a mixture of saltpeter and ground linseed, or similar cake. As a rule, no doubt, the saltpeter would not be present in sufficiently large proportion to produce an explosion, but it is quite possible that some sample of such manure may have accidentally been mixed with a larger

The sample of electronite which failed showed the peculiar behavior of ammonium salts. This sample consisted of amberite No. 1 (nitro-cellulose, nitro-glycerin, paraffin and shellac) mixed with a considerable proportion of ammonium carbonate, and it suffered serious decomposition, even when kept at ordinary temperature.

An invention having for its object the prevention of the mercury fulminate from escaping from detonators, and which consists either in covering the fulminate with a solid disk of celluloid which fits tightly in the case, or in coating the fulminate with collodion, was reported upon favorably, as was an invention consisting in the introduction of glass tubes filled with a strong solution of ammonia into gunpowder blasting cartridges, with a view to diminishing the effect of the flame produced on firing them.

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With the admission of collodion cotton to the "authorized list," a revision in the definition of terms has been made. Hence officially collodion cotton consists of thoroughly purified nitrocotton (a) of which not less than 15 per cent. is soluble in etheralcohol, and (b) which contains not more than 12.3 per cent. of nitrogen," while gun-cotton consists of thoroughly purified nitro-cotton (a) of which not more than 15 per cent. is soluble in ether-alcohol, or (b) which contains more than 12.3 per cent. of nitrogen; and with or without carbonate of calcium." The term nitro-cotton is to be "substituted for nitro-cellulose in the definitions of ballistite, gelatine dynamite, blasting gelatine," etc. It is to be regretted that strictly scientific terms were not adopted at the outset, since much confusion of ideas has resulted from the official classification.

Another new feature in designation is in the use of the terms "percussion cap " and "detonator," as a consequence of the two similar accidents which occurred in the drumming of caps in the Royal Laboratory, Woolwich, on July 24th and August 20th. The drum in which the caps are cleaned is of sheet iron, 2 feet in diameter by 7 inches wide, and at the time of the explosion it was charged with 80,000 caps for the 0.303-in. ball cordite ammunition, each containing 0.4 grain of a composition consisting of mercury fulminate, 6 parts; potassium chlorate, 14 parts; antimony sulphide, 18 parts; powder, mealed, I part; sulphur, ground,

which is turned by hand, had been revolving some three or four minutes when the explosion took place. The explosion partly blew out one side of the drum and scorched the rope mantlet which surrounds it to a height of 6 feet 6 inches, doing no further damage. About 20,000 caps were recovered unexploded. Experiments made to determine the liability of these caps to explode en masse showed that this would not occur unless the caps were raised to a high temperature or mixed with loose composition, but as an additional precaution the dividing line between percussion caps and detonators has been raised above that fixed in Annual Report, 1885, pp. 69, 117, and 1890, p. 53, so that now it is ordered that "a percussion cap to be one containing a charge not exceeding 0.5 grain of composition, or 0.6 grain of composition when the quantity of fulminate of mercury does not exceed one-fourth of such composition; in any other case the cap will rank as a detonator."

In order to identify individual cartridges of explosives, especially when stolen, the German and Belgium governments have recently required that each be marked and numbered. The ingenious method devised by Germany, through which is indicated the factory of origin, date of manufacture, and case in which packed, is described in this report at length with diagrams. After consultation with English manufacturers it was decided that in view of the expense and inconvenience the system entails, and the facility with which the elaborate and costly precautions could apparently be defeated by evil-disposed persons, there was not sufficient warrant for directing the compulsory adoption of such a system.

The comments of Dr. Dupré on an accident at Gover Farm, Abergele, during the burning of rubbish in a grate, illustrates how numerous the causes are which may possibly give rise to explosions. He says: "I have carefully read the further information given, and have also inquired as to what kind of material farmers use that might possibly cause an explosion. I find that some kinds of manures are used consisting of a mixture of saltpeter and ground linseed, or similar cake. As a rule, no doubt, the saltpeter would not be present in sufficiently large proportion to produce an explosion, but it is quite possible that some sample of such manure may have accidentally been mixed with a larger