1888.J on Safety Lamps in Collieries. 207 



15. "Bannocking" or holing the top; the reverse to under- 

 cutting, the charge being put in at the bottom and the explosion 

 acting upwards. 



16. Drilling a hole for a lime cartridge. The anomaly of using 

 gunpowder and safety lamps in the same place is destroyed by the 

 use of caustic lime, which forces out the coal by the expansive action 

 of water on the lime. 



17. The act of watering the lime by pumping. 



18. The result, the fallen coal. 



19. Buildicg a cog-wall — a strong boundary to the "goaf" or 

 gob, which consists of the refuse of the old working and the subsident 

 roof. 



20. Eock " ripping," clearing a roof which has subsided and re- 

 ducing the height of the way, so as to leave room for the horses to go 

 through the old working. This is the most dangerous operation 

 connected with coal mining. 



21. Setting trees or upright timbers to support the roof. Each 

 tree or stanchion has a cap or lid, and they are placed 6 feet 

 apart. 



22. Drawing timber by means of a chain for use again, so as to 

 allow the roof to fall or subside uniformly, and not to break up in 

 pieces. 



23. Examining a waste for gas. This is done two or three times 

 a day by special firemen with the ordinary safety lamp. 



24. Tapping old working for wafer ; a source of great trouble in 

 collieries. 



25. Trying the roof. 



26. A surveying party. A fault in the seam is shown in this 

 slide. 



27. The furnace used for ventilation. This has now been 

 abandoned for more perfect and less wasteful mechanical contri- 

 vances. 



I have shown you most of the operations connected with the win- 

 ning and working of coal ; some of the risks the miner incurs ; some 

 of the troubles arising from gas, water, and falling roofs ; and one of 

 the modes of producing ventilation — the chief prevention of accident. 

 "What our mines could have been in days gone by it is impossible to 

 conceive ; now mechanical appliances are so admirable that many 

 mines are as perfectly ventilated as our homes. The temperature 

 below ground is so uniform — 50° F. at 50 feet, and rising 1° for each 

 55 feet — the formations are so dry that I have actually heard it pro- 

 posed to establish a sanatorium for consumptive patients underground, 

 lighted by electricity, and suj^plied with every luxury. 



All mines are required to have two shafts — one the intake or down- 

 cast, the other the return or up-cast, and the workings are so inter- 

 laced with ways and roads, doors are inserted here and there to direct 

 the current, anemometers are used to measure its rate of flow, that 

 any ordinary inroad of gas is swiftly swept away. Fire-damp, or pit 



