MANUFACTURE, ETC., OF GUNPOWDER. 729 



three of these, the texture of each being closer than that above it, so 

 that large-grain powder is retained on the first, while fine-grain and 

 dust fall through it. The fine-grain remains on the second, and the 

 dust passes on to the third. All the screens are placed in an inclined 

 position, so that the powder runs down them into tubs arranged at the 

 lower end, one of which receives the large, another the fine-grain, and 

 a third the dust. 



The powder is then rolled for some hours in the glazing-barrels, to 

 break off all minute irregularities, and give it a smooth surface. Then 

 it is dried, and finally freed from dust in the slope-reel. This done, it is 

 finished by being passed once more through the glazing-barrels, and 

 it is then packed in barrels of 100 pounds each. 



Such is the process of the gunpowder manufacture in the Royal 

 Factory at Waltham. We have only briefly indicated the principles 

 of each process, for to go into detail would occupy far greater space 

 than is at our command ; but even this sketch will show how at each 

 step science has been called in to aid art in bringing the manufacture 

 to its present high state of perfection. No expense is spared in pro- 

 curing the best materials, the most efficient machines, and the most 

 accurate tests ; yet the cost of manufacture is only about sevenpence 

 per pound. What a contrast to the early days of gunpowder-making, 

 when in France, in 1375, a pound of gunpowder cost a sum equal to ten 

 pounds of our money ! 



In every department the greatest care is taken to prevent the dan- 

 ger of explosions. The houses are built from 200 to 400 yards apart. 

 Wood, copper, and gun-metal, are the only materials used in the struct- 

 ure of the machines, except where, and that rarely, a bolt of iron is 

 introduced for the sake of strength, and then the metal is encased in 

 leather. The floors are covered with hides secured with copper nails, 

 and these, as well as the wooden platforms round the houses, are kept 

 constantly wet. All loose powder is swept away from the floors, 

 damped, and carried to a magazine, where it is collected and the salt- 

 petre subsequently extracted. No one is allowed to enter a room 

 without putting on a pair of leather " magazine shoes " made without 

 nails, as the iron nails in ordinary boots might lead to an explosion if 

 one trod on the loose powder; and, moreover, one would be certain 

 to bring in grains of grit, which are so dangerous if they become mixed 

 with the powder. The men wear a kind of fire-proof clothing, and in 

 the incorporating-houses leather caps and gloves. Fire-engines are 

 stationed in various parts of the factory, and every man has his post as- 

 signed to him in the event of an alarm of fire. To such an extent are 

 these precautions carried that the roofs and eaves of the buildings are 

 searched for birds' nests, and they are pulled down whenever they are 

 found, lest the birds, in building or bringing food to the young, might 

 drop grains of grit or sand on the platforms round the houses. Every 

 building is protected by lightning-conductors, and, as soon as a thun- 



