M. Secchi on Shooting- Stars, 377 



the working of heat-engines, I have not been able to verify the dis- 

 appearance of heat supposed by the dynamical theory to be con- 

 verted into work ; and no experiments that I have been able to 

 devise, or that have, to my knowledge, been made by others, 

 have proved the fact. Hence I have been led to investigate the 

 subject from a different point of view, in the hope of disco- 

 vering some satisfactory clue towards the unravelling of this very 

 intricate inquiry. My chief aim in these pursuits has been, and 

 is, to see a satisfactory application of sound thermo-dynamical 

 principles to the improvement of our heat-engines. An eminent 

 scientific authority has called the practical application of thermo- 

 dynamics "the grandest question of all;" and while our prac- 

 tical engineers and mechanicians should encourage the noble 

 ambition of elevating their technical operations to the rank of 

 true scientific performances, our eminent men of science should 

 not disdain to study in its practical details the Titanic engine 

 which forms one of Britain's noblest boasts; and thus with 

 united energies we may reasonably hope to achieve improve^ 

 ments hitherto unlooked for in our thermic prime movers. 



Palermo, May 23, 1864. 



XLVI. On Shooting-Stars. By Father Secchi*. 



THIS year, as in 1861, the electric telegraph between the 

 observatories at the Collegio Romano and at Civita Vecchia 

 was employed in order to make simultaneous observations, at 

 these places, on the shooting-stars of August. The object of 

 these observations was to determine the height at which these 

 meteors become luminous, and to ascertain the limits of our 

 atmosphere. The observations were commenced on the 5th, 

 and concluded on the 10th of August. There were four obser- 

 vers at Rome, between whom the whole celestial vault was 

 divided; and two at Civita Vecchia, who had instructions to 

 observe the north-eastern half of the heavens from the Great 

 Bear to Aquarius. M. Stabuti and Prof. F. Armellini had the 

 kindness to assist me in these observations ; the former, aided 

 by MM. Bevarno and Caravani at the chronometer, observed at 

 Civita Vecchia ; the latter, together with the other assistants of 

 the observatory, observed with me at Rome. The object of these 

 observations being to fix, precisely, the positions and trajectories, 

 rather than the number of the meteors, many of the latter (con- 

 temporaneous ones included) were neglected when their number 

 prevented the positions of all from being well determined. 



* From a letter to M. E. de Beaumont, published in the Comptes 

 Rendus de VAcademie des Sciences, September 26, 1864. 



Phil. Mag. S. 4. Vol. 28. No. 190. Nov. 1864. 2 C 



