148 REPORT — 1866. 



to 1, and the meau girth of model A was to that of model B as l'4o to 1, the re- 

 sistance of model A was to that of model B in a somewhat less ratio than the 

 latter proportion, though not very much less at moderate speeds. 



4. That the resistance of model A, when just covered with watei', was almost 

 exactly douhle of its resistance at the same speed when half immersed. 



5. That the resistance of model B, when immersed to about three-and-a-half 

 times its depth, was sensibly more than double its resistance when half immersed. 



The author adverted to the great mass of detailed inforjnation as to the propul- 

 sion of vessels which had been accumulated by the late Committee on Steamship 

 performance ; and stated his opinion tliat much good might be done by digesting 

 and condensing that information, which at present was in a form too voluminous 

 for practical use. 



0)1 Bariiiic Poxoder for Heavij Ordnance, Bi/ Captain Wvnants, of tJie 

 lioyal Belr/ian Artillerif. Communicated hi/ Charles Vignoles., F.R.S., 

 M.R.I. A. ' 



This particular kind of powder has been much experimented upon, both in Bel- 

 gium and in France, with a view to counteract the injurious elfect which is pro- 

 duced when large charges of powder are used in heavy ordnance. The principle 

 on whicli this barytic powder is compounded is simply that of substituting nitrate 

 of barytes in the composition of tlie gunpowder, instead of saltpetre, in certain 

 proportions, the consequence being that the powder, when ignited, consumes more 

 slowh', and the gases are developed less rapidly than in ordinary gunpowder, 

 while the same effect is produced upon the projectile as regards its ultimate 

 velocity. This lessens the injmious efiect upon tlie sides, vent, and chamber of the 

 piece of artillery. Capt. Wynants entered into the details of a very large number 

 of experiments made with this powder. The general result to be deduced from 

 these experiments is, that we have to choose between imparting a higher degi'ee of 

 velocity to the projectile, at the risk of damaging the piece more rapidly and more 

 considerably, or confining oin* attention to the American plan of projecting heavier 

 shot at a lower velocity. The preponderating feeling in the minds of English 

 engineers and artillerists, and particularly of sailors, is for a higher degree of 

 velocity, with a smaller weight of shot. The question is an exceedingly interest- 

 ing one, and lias excited considerable attention both in Belgium and in France, as 

 it has done in Prussia and America. If these experiments could be continued, we 

 should obtain some very useful information on the subject. Capt. Wynants con- 

 sidered that the principal difficulty in dealing with the present enormous artillery 

 arose from the too rapid consumption of the powder, by which the generation of 

 gas was so rapid that the interior of the gun was destriictivelv atfocted before the 

 projectile was moved. Capt. Wjiiants found that by substituting nitrate of barytes 

 for saltpetre in the composition of gunpowder the rapidity of the combustion was 

 reduced without the propelling force of the powder lieing diminished — in fact, the 

 propelling force was rendered more uniform in its action. 



