EXPLOSIONS IN COAL-MINES AND REVOLVING STORMS. 5 



Wick in Scotland, Dublin and Newcastle-upon-Tyne, Dover, and Oporto, 

 to illustrate the successive phases of the cyclone during its passage over these 

 respective places. At Wick, the wind shifts from S.E. through E. to N., 

 and blows hardest at E.N.E. At Dover, the wind shifts from S. through W. 

 to N.W., and blows hardest at W.S.W. At Oporto, the wind shifts from 

 S.W. to W., and blows hardest at W.S.W. 



The centre passes over Dublin and Newcastle-upon-Tyne, where the wind 

 shifts abruptly from S.S.E. to N.N.W., a short lull probably preceding the 

 change of wind. Here the mercury falls lowest. 



Since all the different coal-fields of Britain are sometimes subjected to the 

 action of one cyclone at the same time, the occurrence oi nearly simultaneous 

 explosions in mines far apart may be anticipated ; and since storms travel 

 towards the E.N.E., explosions in the coal-mines of France, Belgium, &c. 

 will sometimes happen a day or two after a great storm has passed over the 

 British Islands. If the number of such cases is found to be considerable, it 

 will be a strong proof of the connexion between revolving storms and explo- 

 sions in coal-mines. This proof will be confirmed by our finding that after 

 an entire absence of explosions for many weeks, several occur almost simul- 

 taneously, just after the arrival at Britain of some extraordinary atmospheric 

 paroxysm, which has already devastated the islands and shores of the Gulf of 

 Mexico, and the sea-board of the United States, and left several wrecked and 

 disabled ships in the rear during its eastward course across the Atlantic. 



Unfortunately our mining records are defective with regard to two large 

 classes of phsenomena, which are eligible as evidence in this inquiry. 

 They seldom notice explosions which have not been fatal to human life, and 

 they contain no account of cases like those at Jarrow in 1839, where mines 

 have been filled with gas during stormy weather, and explosions have been 

 prevented. 



In order [to ascertain the relation between explosions and the seasons of 

 the year, Mr. Taylor has arranged, in monthly periods, a table of 115 of the 

 chief explosions during forty years in the north of England (Pari. Report, 

 &c., 184.9, p. 572). 



Up to the end of 1854' there are recorded 514> explosions in British coal- 

 mines. With these I have constructed, in monthly periods, the curve A 

 (Plate II.), which agrees remarkably well with the corresponding curve B, 

 formed from the 115 explosions selected by Mr. Taylor. In the curve C, I 

 have grouped all the explosions (491) of which the day of occurrence is 

 known, in 73 periods of 5 days each. The minimum for the year in A is 23, 

 and falls in February ; in B is 3, and falls in January and February ; and ia 

 C is 1, and falls in January 20-25. 



The maximum for the year in A is 55, and falls in June ; in B is 15, and 

 falls in June and December ; in C is 12, and falls June 9-14, and July 9-14. 



The persistent character of these curves, with respect to the places of their 

 maxima and minima, proves indisputably the 5'e/«era/ dependence of explosions 

 in coal-mines upon the seasons of the year. 



The lowest temperature of the year occurs between the middle of January 

 and the middle of February. The ventilation of mines is consequently most 

 active during these months ; and accordingly the curves show that this is the 

 season least liable to explosions. 



As the temperature increases, explosions are more frequent, until thehighest 

 temperature and the greatest number of explosions take place together in June 

 and July. In September the curve descends, that is, the number of explo- 

 sions is less as the temperature decreases. The rise of the curve at the end of 

 September, and the great number of explosions in October, November, and 



