2 SMirilSONIAN MISCEI.I.AMCOrS COLLKCriONS VOL. /I 



even in the case of the Coston ship rocket, which was found to have a 

 range of a quarter of a mile. 



Experiments were next performed with the object of increasing 

 the average velocity of ejection of the gases. Charges of dense 

 smokeless powder were fired in strong steel chambers (fig. 2, p. 13), 

 these chambers being provided with smooth tapered nozzles, the 

 object of which was to obtain the work of expansion of the gases, 

 much as is done in the De Laval steam turbine. The efficiencies and 

 velocities obtained in this way were remarkably high (table II, p. 15), 

 the highest efficiency, or rather " duty," being over 64 per cent, and 

 the highest average velocity of ejection being slightly under 8,000 

 ft./sec, which exceeds any velocity hitherto attained by matter in 

 appreciable amounts. 



These velocities were proved to be real velocities, and not merely 

 effects due to reaction against the air, by firing the same steel cham- 

 bers in vacuo, and observing the recoil. The velocities obtained in 

 this way were not much different from those obtained in air ( table III, 



P-30)- 



It will be evident that a heavy steel chamber, such as was used in 

 the above-mentioned experiments, could not compete with the ordi- 

 nary rocket, even with the high velocities which were obtained. If, 

 however, successive charges were fired in the same chamber, much as 

 in a rapid fire gun, most of the mass of the rocket could consist of 

 propellant, and the superiority over the ordinary rocket could be 

 increased enormously. Such reloading mechanisms, together with 

 what is termed a " primary and secondary " rocket principle, are the 

 subject of certain United States Letters Patent (p. 6). Inasmuch 

 as these two features are self-evidently operative, it was not con- 

 sidered necessary to perform experiments concerning them, in order 

 to be certain of the practicability of the general method. 



Regarding the heights that could be reached by the above method ; 

 an application of the theory to Cases which the experiments show 

 must be realizable in practice indicates that a mass of one pound 

 could be elevated to altitudes of 35, y2, and 232 miles ; by employing 

 initial masses of from 3.6 to 12.6, from 5.1 to 24.3, and from 9.8 to 

 89.6 pounds, respectively (table VII, p. 46). If a device of the 

 Coston ship rocket type were used instead, the initial masses would 

 be of the order of magnitude of those above, raised to the 2/th pozver. 

 It should be understood that if the mass of the recording instru- 

 ments alone w^ere one pound, the entire final mass would be 3 or 4 

 pounds. 



