204 Mr. William Henry Preece [Feb. 10, 



WEEKLY EVENING MEETING, 



Friday, February 10, 1888. 



His Grace the Duke of Noethumberland, K.G. D.C.L. LL.D. 



President, in tbe Chair. 



William Henry Preece, Esq. F.K.S. MM.I. 



Safety Lamps in Collieries. 



On a fine summer's day the sun expends an average of one horse- 

 power on every 30 square feet of the earth's surface in this latitude, 

 or 1450 horse-power per acre. This great gift of energy is neither 

 utilised nor stored by man at present, though Nature presents us 

 with some of it in waterfalls and flowing streams. The sun itself 

 has been more generous. Ages upon ages ago it shone with resplen- 

 dent glory on a grand luxuriant flora of a uniform but flowerless 

 character in a climate warm and damp. England formed part of a 

 tropical jungle or swamp, where grasses, mosses, ferns, and sedges, 

 coniferse, araucaride, equisetaccse, sigillarise grew and flourished, perished 

 and fell in situ, to be covered up by the following geological forma- 

 tions and compressed into those grand seams of coal that form now 

 the principal source of England's greatness and wealth. If language 

 be fossil poetry and words condensed history, then coal may be 

 derived from coelum or kolXo^ (Jcoilos), and imply a Heaven-sent gift. 



The first authentic account of coal digging dates from the reign 

 of Henry III., when Newcastle sent its first cargoes by sea to London, 

 and thus gave the mineral the name of sea-coal. Early records of 

 the output of coal are wanting. 



In 1700 it was 2,614,000 tons. 

 In 1800 it was 10,000,000 tons. 

 In 1850 it reached 42,000,000 tons. 

 In 1886 it reached 157,518,482 tons. 



A ton of coal occupies very nearly a cubic yard of space. Hence 

 this quantity of coal, if placed in Hyde Park, would form a mountain 

 as high as Snowdon, and if erected as a wall around the coast-line of 

 Great Britain, it would be 6 ft. wide and 30 ft. high. It would form 

 a girdle round the world 3 ft. wide and 12 ft. high. We extract from 

 the earth twenty times more energy than the sun can possibly restore 

 to it by the growth of forest, and we are gradually but surely tending 

 towards the time when this store of power, heat, and light, will be 

 exhausted, when our busy hives of industry must seek other shores, 

 and when England will perhaps become a summer resort for a wealthy 

 Anglo-Saxon race occupying other quarters of the globe. 



