----------------------------+---------------------------------------- Brand. | Manufacturer. ----------------------------+---------------------------------------- Ætna coal powder A | Ætna Powder Co., Chicago, Ill. Ætna coal powder B | Do. Carbonite No. 1 | E. I. Dupont de Nemours Powder Co., | Wilmington, Del. Carbonite No. 2 | E. I. Du Pont de Nemours Powder Co., | Wilmington, Del. Carbonite No. 3 | Do. Carbonite No. 1 L. F. | Do. Carbonite No. 2 L. F. | Do. Coal special No. 1 | Keystone Powder Co., Emporium, Pa. Coal special No. 2 | Do. Coalite No. 1 | Potts Powder Co., New York City. Coalite No. 2 D | Do. Collier dynamite No. 2 | Sinnamahoning Powder Co., Emporium, Pa. Collier dynamite No. 4 | Do. Collier dynamite No. 5 | Do. Masurite M. L. F. | Masurite Explosive Co., Sharon, Pa. Meteor dynamite | E. I. Du Pont de Nemours Powder Co., | Wilmington, Del. Monobel | Do. ----------------------------+---------------------------------------- “Subject to the conditions named below, a permissible explosive is defined as an explosive which has passed gas and dust gallery tests Nos. 1, 2, and 3 as described above, and of which in test No. 4 1½ pounds (680 grams) of the explosive has been fired into the mixture there described without causing an ignition. “_Provided:_ “1. That the explosive is in all respects similar to the sample submitted by the manufacturer for test. “2. That double-strength detonators are used of not less strength than 1 gram charge consisting by weight of 90 parts of mercury fulminate and 10 parts of potassium chlorate (or its equivalent), except for the explosive ‘Masurite M. L. F.’ for which the detonator shall be of not less strength than 1½ grams charge. “3. That the explosive, if in a frozen condition, shall be thoroughly thawed in a safe and suitable manner before use. “4. That the amount used in practice does not exceed 1½ pounds (680 grams) properly tamped. “The above partial list includes the permissible explosives that have passed these tests prior to May 15, 1909. The announcement of the passing of like tests by other explosives will be made public immediately after the completion of the tests for such explosives. “A description of the method followed in making these and the many additional tests to which each explosive is subjected, together with the full data obtained in each case, will be published by the Survey at an early date. “NOTES AND SUGGESTIONS.