16J theory of the motion of ROCKltTS. 



a proper enquiry could not but have been instituted con- 

 cerning his pretensions. 



I herewith send you a further continuation of my essay 

 on the motion, &c. of these machines, which 1 hope will 

 be found worthy your acceptance ; »nd am. 



Sir, 

 Your much obliged humble servant, 



W. MOORE, 



Royal Academijt Woolwich, 



Jan. 1811. ' 



Pjtop. IL 



To determine the path of a rochet near the Earth^i surface^ 

 neglecting the resistance of the atmosphere. 



Path of a If during the time the rocket was on fire, the weight of 



rocket in a 

 nonresistinj 



the whole mass remained conftant, the path of the rocket 

 medium. would, by mechanics, be a straight line: but this being 



not the case on account of the continual wasting of the 

 matter which feeds the flame of the rocket, the accelera- 

 tive force of the body will be different at every instant ; 

 and therefore, since the accelerative force of gravity (as we 

 will suppose) is constant to the height which rockets gene- 

 rally ascend, the rout of the rocket will consequently be a 

 curvilinear one. 



Now, although gravity acts to impel the rocket from a 

 straight course, yet it does not hinder the same from arriving 



at 



