HENRY AUGUSTUS ROWLAND 417 



are striking evidences of the value of the grating; the additions to 

 our knowledge arising from this one discovery are already enor- 

 mous; much has been achieved which, without it, would have 

 been impossible." 



When he went to Paris in 1881 he took some of his photographs 

 and gratings with him. In a letter to President Oilman, Professor 

 John Trowbridge of Harvard gives an interesting account of 

 Rowland's reception. A part of that letter should be quoted here: 



"Rowland invited Mascart, Sir W. Thomson, Wiedemann, Ros- 

 setti, and Kohlrausch to his room at the Hotel Continental in 

 Paris, and showed them his photographs and gratings. It is need- 

 less to say that they were astonished. Mascart kept muttering 

 'Superbe' ' Magnifique.' The Germans spread their palms and 

 looked as if they wished they had ventral fins and tails to express 

 their sentiments. Sir W. Thomson evidently knew very little 

 about the subject, and maintained a wholesome reticence, but 

 looked his admiration for he knows a good thing when he sees it, 

 and also had the look that he could express himself upon the whole 

 subject in fifteen minutes, when he got back to Glasgow. 



"In England, Rowland's success was better appreciated, if 

 possible, than in Paris. He read a paper before a very full meet- 

 ing of the Physical Society De la Rive, Professor Dewar of 

 Cambridge Professor Clifton of Oxford, Professor Adams (of 

 Leverrier fame), Professor Carey Foster, Hilger, the optician, 

 Professor Guthrie, and other noted men being present. I was 

 delighted to see his success. The English men of science were 

 actually dumbfounded. Rowland spoke extremely well, for he 

 was full of his subject, and his dry humor was much appreciated 

 by his English audience. When he said that he could do as much 

 in an hour as had hitherto been accomplished in three years, there 

 was a sigh of astonishment and then cries of 'Hear! Hear!' Pro- 

 fessor Dewar arose and said: 'We have heard from Professor Row- 

 land that he can do as much in an hour as has been done hitherto 

 in three years. I struggle with a very mixed feeling of elation and 

 depression: elation for the wonderful gain to science; and depres- 

 sion for myself, for I have been at work for three years in mapping 

 the ultra violet. ' De la Rive asked how many lines could be ruled 

 by Rowland. The latter replied: 'I have ruled 43,000 to the inch, 

 and I can rule 1,000,000 to the inch, but what would be the use? 

 No one would ever know that I had really done it.' Laughter 

 greeted this sally. The young American was like the Yosemite, 



