1872.] 



between Explosions in Collieries and Weather. 



305 



Jarrow in 1839, where mines have been filled with gas during stormy- 

 weather, and explosions have been prevented." 



Whether, therefore, the barometer falls or the temperature rises it is 

 absolutely necessary to keep a most careful watch over the amount of air 

 passing through the workings, in order to prevent the formation of dan- 

 gerous accumulations of explosive mixtures of air and fire-damp in all 

 mines in which the margin between danger and safety is very small. 



In a letter to the South-Shields Committee in 1843, George Stephenson 

 said, referring to explosions, "Generally speaking, there has been some 

 % fault in the ventilation of the mines when accidents have occurred." A 

 similar opinion was expressed by most of the gentlemen who were consulted 

 when at the beginning of the year 1868 the Meteorological Committee 

 proposed to send telegraphic intelligence of storms to colliery proprietors. 



The one cry, whether we look to security against explosion, or to afford- 

 ing to miners an atmosphere which is respirable without injury to health, 

 is more air. 



EXPLANATION OF THE PLATE. 



The dark line is the curve of the barometer, the faint line that of the thermometer 

 at the Observatory of Stonyhurst, near Preston, taken from the continuous records for 

 the years 1868, 1869, 1870. 



The explosions which are apparently due to a fall of the barometer are shown by 

 squares. 



The explosions which are apparently due to a rise of the thermometer are shown by 

 circles. 



The explosions which are apparently not caused by either agency are shown by 

 triangles. 



The bar across the symbol for an explosion indicates that it was fatal. 

 Sundays are marked by a line near the base of the diagram. 



The districts in which the respective explosions occurred are indicated by figures, the 

 explanation of which is as follows : — 



1. South Durham. 



2. North and East Lancashire, or Manchester. 



3. South-west Lancashire and North Wales. 



4. Midland. 



5. North Staffordshire, Cheshire, and Shropshire. 



6. South-western (Monmouthshire &c). 



7. South Staffordshire and Worcestershire. 



8. South Wales. 



9. Northumberland, North Durham, Cumberland. 



10. Yorkshire. 



11. East of Scotland. 



12. West of Scotland. 



