Progress of Invention. 475 



ting rid of very large quantities of very troublesome material, but a 

 source of considerable profit. 



New Mode op Maneuvering a Vessel. — Floating batteries are 

 being constructed for the protection of tbe coasts of Sweden. They 

 are provided with a turret : and as the turret does not revolve, in 

 order to secure the power of aiming the gun it contains in all direc- 

 tions, it is necessary that the vessel itself should rapidly turn round. 

 This is effected with ease and certainty, by means of a paddle wheel 

 fixed at the bow, and turning on an axis which is parallel to the 

 length of the vessel. This wheel is entirely immersed and 

 therefore if constructed in the ordinary way with fixed floats, it 

 would produce no motion, the floats on opposite sides neutralzing 

 each other. It is therefore so arranged that the floats, when in a 

 higher position feather, and move through the water horizontally so 

 as to have no effect in producing motion. The floats which are at 

 the time in a lower position produce a maximum effect. This 

 paddle wheel offered little resistance to the progressive motion of 

 the floating battery as the floats are made of thin sheet iron : and 

 they present their edges to the direction in which the vessel is 

 moved. Such an arrangement would however not be suitable 

 with other than vessels intended to remain constantly at or very 

 near the same place. 



Production op Detonating Powder, with the Materials op 

 Ordinary Gunpowder. — It has been found, that the rapidity of com- 

 bustion of gunpowder depends greatly on the nature of the charcoal 

 employed ; the development of this fact has been carried so far, by 

 a suitable selection of the charcoal, that the combustion becomes so 

 rapid as to be an explosion of the unconfined powder. This is 

 effected by the use of carbon obtained from rice starch, the albumen 

 of blood, or leather. With nitrate of potash such carbon forms not 

 ordinary gunpowder but a detonating material. 



