PROGRESS IIST EXPLOSIVES GUTTMANN. 271 



ing is usually completed in centrifugals. In order to obtain the best 

 quality, melting between 81° and 82° C, trinitrotoluene made from 

 purified toluene, and having a melting point of 77° to 79° C, is 

 recrystallized from alcohol in vacuo. The machinery for effecting 

 this is not very complicated, but always specially designed. In this 

 country alcohol is somewhat dear and inconvenient to use, in spite 

 of facilities afforded for obtaining it duty free, and petroleum ben- 

 zine is therefore employed for recrystallizing the trinitrotoluene; it 

 is said, however, that a slightly darker color is imparted by this 

 method to the product, to which objection is taken in some countries. 



Tlie density of trinitrotoluene when loose being 1.50 and when 

 molten 1.600^ means have been devised to increase it. Rudeloff °' ob- 

 tains a density of 1.85 to 1.90 by making a plastic substance from 

 trinitrotoluene and potassium chlorate with a gelatine made from 

 dinitrotoluene and soluble nitrocellulose. Bichel makes a plastic com- 

 pound with collodion cotton, liquid dinitrotoluene, and larch turpen- 

 tine, calling it plastrotyl.^ Messrs. Allendorff mix the trinitrotoluene, 

 together with some lead nitrate or chlorate, with a gelatine made from 

 dinitrotoluene and nitrocellulose, and call it triplastit. This is an 

 improvement on the way the French Government made melinite with 

 collodion, or Wolff' & Co. filled gun-cotton slabs into shells with 

 paraffin wax. Bichel also melts the trinitrotoluene, and after first 

 exhausting all occluded air, compresses it by introducing compressed 

 air above it.^ Bichel has in this way obtained densities up to 1.69. 

 Rudeloff presses it in hydraulic presses under a pressure of 2,000 to 

 3,000 atmospheres, whereby it obtains a density of 1.7, and can be cut 

 and worked like gun cotton. For the purpose of facilitating detona- 

 tion, some loose trinitrotoluene is used as a primer. Trinitrotoluene 

 is also used in detonators, of which further mention will be made 

 later on. 



Another new explosive for filling shells is used in Spain under the 

 name of tetralit.'' It is said to be made from tetranitromethylamine, 

 and to be more sensitive than trinitrotoluene, but very little else is 

 known. 



During the last three or four years newspapers contained accounts 

 of trials with a new explosive, at first called vigorite and now bava- 

 rite, the invention of Professor Schulz and Mr. Gehre, which is said 

 to cost only one-third as much as other explosives, and to be ever so 

 much more powerful. On examining the patent ^ one finds that this 



« " Zeitschrift fiir das gesamte Scliiess- und Sprengstoftwesen," 1907, p. 7. 



6 British patent No. 16882, of 1906. 



(^ Id., No. 19215, of 1906. 



^ " Zeitschrift fiir das gesamte Schiess- und SprengstofCwesen," 1908, p. 308. 



e British patent No. 5687, of 1905. 



