366 Royal Society : — 



" Description of a mutilated skull of a large Marsupial Carnivore 

 (Thylacoleo Carnifex, Ow.), from a conglomerate stratum, eighty 

 miles S.W. of Melbourne, Australia." By Professor R. Owen, 

 F.R.S. &c. 



" On the Nature of the Action of Fired Gunpowder." By Lynall 

 Thomas, Esq. 



Since the year 1 797, when Count Rumford made his experiments 

 for ascertaining the initial force of fired gunpowder, an account of 

 which appears in the Philosophical Transactions of that year, very 

 little light has been thrown on the subject. Count Rumford's ex- 

 periments, valuable in many respects, afforded indeed nothing con- 

 clusive respecting it. 



The object of the present paper is to show the unsatisfactory nature 

 of the present theory of the action of gunpowder, and to point out 

 some of the principal errors upon which this theory is based. For 

 this purpose, the results of various experiments made by the author, 

 and which were repeated in the presence of a Select Committee at 

 Woolwich, are described and explained. 



These experiments are held by the author not only to afford com- 

 plete evidence of the unsoundness of the present theory, but as 

 sufficiently conclusive to serve as a basis for the formation of a new 

 set of formulae, both correct and simple, in place of those at present 

 in use. 



The initial action of the fired charge of powder upon the shot, — 

 the first movement of the shot itself in the gun, — and the force exerted 

 upon the gun by different charges of powder, — and, therefore, the 

 actual strength of metal required for the gun, — are circumstances, 

 wbich, as the author believes, have not only been misunderstood, but 

 for which laws have been assigned directly opposed to the truth. 



As an instance of this, the hitherto received theory supposes 

 that when a shot is fired from a gun, it acquires its velocity gradually, 

 .from the pressure of the elastic fluid generated by the tired powder 

 acting upon it through a certain space. It is also supposed that the 

 initial pressvire of this elastic fluid is the same in all cases (the quantities 

 of powder being proportional), whether the gun from which the shot is 

 fired be large or small ; so that the larger the calibre of the gun, the 

 slower the first movement of the shot is supposed to be. The result 

 of the following experiment is given to prove that the first of these 

 propositions is incorrect. The author placed a cast-iron shot 3 inches 

 in diameter and 3 lbs. 14 ozs. in weight upon a chamber half an inch 

 in diameter and half an inch deep. This chamber was formed in a 

 block of gun-metal, and contained, when filled, one dram of powder. 

 Upon lighting the powder, the ball was driven to a height of 5 feet 6 

 inches ; when the ball was placed at ^ of an inch over the chamber, 

 the charge failed to move it. 



From this it is inferred that the first force of the powder is an hnpul- 

 sive force, that is to say, it imparts to the shot at once a finite velocity. 

 In order to place the matter beyond a doubt, and to ascertain the 

 relative force of different quantities of powder, the author caused a 



