120 A Few Additional Bemarhs on 



Because of these circumstances, the results were not satisfactory 

 to me. I therefore did not puhhsh them, nor even speak of them 

 beyond a Hmited circle of my acquaintances. I even "went so far as 

 to ignore them altogether when speaking on the subject in public ; 

 not regarding them as sufficiently important to justify me in quali- 

 fying the expression of opinion quoted by Col. "Woodward in the 

 January number of this Journal, that the lines of the nineteenth 

 band had " never been fairly resolved." 



My results and my method of reaching them were communi- 

 cated to Mr. Stodder in response to a request made directly to me 

 by him. He published them, and they became subject of criticism 

 by Col. Woodward. Had Col. Woodward confined his criticism to 

 the results, I should have had nothing to say ; but inasmuch as he 

 attacked the principle on which I proceeded, I felt bound to vindi- 

 cate the principle as one which is unquestionably sound. I could 

 not vindicate the principle without referring to the observations for 

 illustration. If in doing this I have seemed to " reconsider " my 

 opinion formerly expressed as to the value of those observations, it 

 is simply because he has made it a logical necessity for me to do so. 

 I certainly saw something and counted something. No subsequent 

 expression of opinion of mine can alter that fact. And in order 

 that the readers of the Journal might be in possession of the 

 whole case, I should wish to place before them all the original 

 minutes of the observations, if it were in my power. They have 

 been mislaid, but I think not lost; and I hope to publish them 

 hereafter. In searching for them I have encountered a series of 

 observations made in the following year, when the dry-working 

 front of the objective had been replaced by an immersion front by 

 Tolles. The following examples, copied literally from the notes, 

 will illustrate the mode of proceeding. In the first four bands the 

 entire breadth of the band is measured : in the nineteenth, the 

 measurement extends to only twenty divisions. The second number 

 of each equation is the equivalent number of the micrometer. 



Itt Band. — - line = 1161 div. 6 lines = 1,161,000 div. 



1 line = 193,500 div. 



2nd Bund. — — line = 1159 div. 9 lines = 1,738,500 div. 



1 line = 193,167 div. 

 12 

 3rd Band. — — line = 1158 div. 12 lines = 2,316,000 div. 



1 line = 193,000 div. 



4th Band. -^ line = 1076 div. 14 lines = 2,690,000 div. 



2500 



20 

 19tb Band. 7^^7^7:^11116= 391 div. 2 lines = 391,000 div. 



10000 

 Objective, -J^th immersion 



1 line = 192,143 div. 



2 lines = 391,000 div. 

 1 line = 19.5,500 div. 



