48 On the Iron Meteorite 



'*I took several photographs, but in truth they did not prove 

 satisfactory. Either from the difficulty in focussing, or because 

 r did not expose them for the pro])er length of time, the nega- 

 tives did not seem worthy of mention after I had examined them 

 on the day following. After an exposure, I could not develop 

 the negatives at once, for fear of Josing my observations ; and to 

 develop them was the only test which would have given me an 

 index as to the j^roper time necessnry. 



" With the spectroscope I w.is more successful. To my equa- 

 torial, of six inches aperture, I connected a direct-vision Secchi 

 spectroscope with five prisms and cylindrical lens. The spectra 

 which I noted of the falling stars were all identical. They pre- 

 sented a continuous spectrum with the characteristic lines of 

 ISodium, Carbon, Iron, Nickel and Magnesium. I had never 

 seen the atmospheric lines of nitrogen so marked and character- 

 istic, even when observing the sun near the horizon. The ex- 

 istence of these nitrogen (azote) lines I explain by the extremely 

 high temperature acquired by the air from the contact of the me- 

 teors. It is estimated by some that, on coming into the terres- 

 trial atmosphere, these bodies possess a speed of from 30 to 60 

 kilometers per second (Wiess estimates 14.9), and that the air 

 so violently compressed instantly acquires a temperature of 3000 

 to 4000 degrees. 



" It was impossible for me to determine the trajectory of this 

 maze of stars, as they were flying in all directions like firework- 

 bombs ; nevertheless, the greater number started from a radial 

 point in the direction e Persei and Algol. 



''As to the number of stars which fell into the atmosphere 

 from 6.20 P. M. until three in the morning — when a thick mist 

 from the northeast prevented further obsei'vation^ — it was impos- 

 sible to fix accurately, from the multiplicity of duties which en- 

 grossed me. However, my assistant, who was charged with this 

 duty, pencil in hand, and marking from time to time the num- 

 ber counted, noted twenty-seven hundred and twenty meteors, 

 or a little over five per minute. 



"Other persons, to whom I had recommended the study of 

 the phenomenon, living at various points in the State of Zacate- 

 cas, have probably over-estimated the number seen, since one in 

 particular assured me he had counted nearly 6000. Most of 



