Father Secchi on the recent Solar Discoveries. 63 



Passing from these major points, then, which, as I said before, 

 I am content to leave to the future, there are several minor 

 ones on which I beg the Academy will allow me to say a few 

 words. 



Father Secchi says, " Lorsque M. Lockyer affirme m'avoir pre- 

 cede dans les observations des injections de magnesium, on ne 

 peut pas dire jusqu'a. quel point cela est exact." So far as the 

 mere question of priority goes, I should not think this remark worth 

 answering ; but as Father Secchi seems to cast doubt on my ve- 

 racity, I beg to refer him to a paper communicated to the Royal 

 Society on March 4, 1869, the first observations, as there stated, 

 having been made on February 21 and 28. With regard to his 

 assertion, " J'ai clairement vu et demontre que seulement une 

 ligne du magnesium est renversee et que Pautre ligne brillante oc- 

 cupe Fespace intermediate des deux plus voisines," I feel my- 

 self justified in denying the accuracy of the observation, and I 

 leave this, like the other questions, to be decided by the future. 

 I should not venture to do this if a long series of experiments at 

 the Royal College of Chemistry had not been absolutely in ac- 

 cord with my telescopic observations which have already been 

 described in the Comptes Rendus. 



M. Secchi objects to my mixing up theory and observations. 

 I plead guilty. 1 confess a remark made some time ago by M. 

 Faye is always present with me when I am observing. The re- 

 mark is, "A good theory is as necessary as a good telescope." 

 Without a working hypothesis, I should certainly have cross- 

 questioned the sun much less than I have done ; and it should 

 be a truism that in a research, such as the one we are now 

 conducting, it will not do to observe blindly or haphazard. For 

 instance, I began on the generally received theory that the ab- 

 sorption took place outside the photosphere, which is evidently 

 Father Secchi's present idea, as shown by the extract from one 

 of his latest communications I have already given, but by testing 

 the theory in every way, I found it untenable; and I venture to 

 think that if Father Secchi had done the same, there would have 

 been less contradiction in his statements, and he also would 

 have found such a theory untenable. But I confess that the 

 remark that it is too soon to theorize, coming from Father Secchi, 

 somewhat surprises me ; for I find very many theories referred 

 to in his earliest papers on the subject. 



In my former paper I stated, " si la chromosphere etait sus- 

 pendue h une certaine distance de la photosphere, nous ne pour- 

 rions trouver un elargissement du a la pression." On this 

 Father Secchi remarks that he does not see the justice of my 

 conclusion. This may arise from the fact that he does not 

 agree that the F line widens by pressure ; that is, if he elects 



