586 



In the marsupial order, the present large extinct Carnivore, for 

 which the author proposes the name of ' Thylacoleo * carnifex,' 

 is most nearly allied to the Dasyurus (Sarcophilus) ur sinus ; but is 

 very different in its dentition from that and all existing Carnivora. 



The fossils described were discovered by William Adeney, Esq., in 

 a calcareous conglomerate stratum in a bank of a lake situated 80 

 miles south-west of Melbourne, Australia. 



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

 LYNALL THOMAS,, Esq. Communicated by Dr. GRAY. 

 Received November 17, 1858. 



(Abstract.) 



Since the year 1797, 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, 

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

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

 * From OvXaicos, a pouch ; Xewv, a lion. 



