~Indurite~ is the invention of Professor C.E. Munroe, of the U.S. Naval Torpedo Station. It is made from insoluble nitro-cotton, treated in a particular manner by steam, and mixed with nitro-benzene. The _Dupont_ powder is very similar to _Indurite_. M.E. Leonard, of the United States, invented a powder consisting of 75 parts of nitro-glycerine, 25 parts of gun-cotton, 5 parts of lycopodium powder, and 4 parts of urea crystals dissolved in acetone. The French smokeless powder, Vielle poudre (poudre B), used in the Lebel rifle, is a mixture of nitro-cellulose and tannin, mixed with barium and potassium nitrates. It gives a very feeble report, and very little bluish smoke. The Nobel Company is said to be perfecting a smokeless powder in which the chief ingredients are nitro-amido- and tri- nitro-benzene. C.O. Lundholm has patented (U.S. Pat, 701,591, 1901) a smokeless powder containing nitro-glycerine 30, nitro-cellulose 60, diamyl phthalate 10 (or diamyl phthalate 5, and mineral jelly 5). The diamyl phthalate is added, with or without the mineral jelly to nitro-glycerine and nitro-cellulose. ~Walsrode Powder.~--The smokeless powder known as Walsrode powder consists of absolutely pure gelatinised nitro-cellulose, grained by a chemical not a mechanical process, consequently the grains do not need facing with gelatine to prevent their breaking up, as is the case with many nitro powders. For this same reason, as well as from the method of getting rid of the solvent used, the Walsrode has no tendency whatever to absorb moisture. In fact, it can lie in water for several days, and when taken out and dried again at a moderate temperature will be found as good as before. Nor is it influenced by heat, whether dry or damp, and it can be stored for years without being in the least affected. It is claimed also that it heats the barrels of guns much less than black powder, and does not injure them. The standard charge is 30 grains, and it is claimed that with this charge Walsrode powder will prove second to none. A large cap is necessary, as the grains of this powder are very hard, and require a large flame to properly ignite them. In loading cartridges for sporting purposes, an extra felt wad is required to compensate for the small space occupied by the charge; but for military use the powder can be left quite loose. The gas pressure of this powder is low (in several military rifles only one- half that of other nitros), and the recoil consequently small; and it is claimed that with the slight increase of the charge (from 29 to 30 grs.) both penetration and initial velocity will be largely increased, whilst the gas pressure and recoil will not be greater.