A series of experiments of great interest and vital importance to
colliery owners and all those engaged in mining coal has been carried
out during the last ten days in the South Yorkshire coal field. The
new mines regulation act provides that any explosible used in coal
mines shall either be fired in a water cartridge or be of such a
nature that it cannot inflame firedamp. This indeed is the problem
which has puzzled many able chemists during the last few years, and
which Dr. Roth, of Berlin, claims to have solved with his explosive
"roburite." We recently gave a detailed account of trials carried out
at the School of Military Engineering, Chatham, to test the safety and
strength of roburite, as compared with gun cotton, dynamite, and
blasting gelatine. The results were conclusive of the great power of
the new explosive, and so far fully confirmed the reports of the able
mining engineer and the chemical experts who had been sent to Germany
to make full inquiries. These gentlemen had ample opportunity of
seeing roburite used in the coal mines of Westphalia, and it was
mainly upon their testimony that the patents for the British empire
were acquired by the Roburite Explosive Company.

It has, however, been deemed advisable to give practical proof to
those who would have to use it, that roburite possesses all the high
qualities claimed for it, and hence separate and independent trials
have been arranged in such representative collieries as the
Wharncliffe Silkstone, near Sheffield, Monk Bretton, near Barnsley,
and, further north, in the Durham coal field, at Lord Londonderry's
Seaham and Silksworth collieries. Mr. G.B. Walker, resident manager of
the Wharncliffe Colliery Company, had gone to Germany as an
independent observer--provided with a letter of introduction from the