LIV BULLETIN NO. 23, UNITED STATES NATIONAL MUSEUM. . 



British Muskum, February 21, 1871. 



Dear Dr. Lea : I have been favored by, I believe, every evidence of your most 

 valuable and untiring labors on the Unionidce, and none more do I value than the vol- 

 ume I have just received, your admirable and instructive " Synopsis," quarto, 1870. 

 I thank you most sincerely for these indispensable bodies of instruction in my library 

 of reference, and for the kindly, friendly, spirit in which they have been transmitted. 

 They represent a kind or class of labors, the most genuine and important* and last- 

 ing, in the hard endeavor to gain a knowledge of nature. They worthily represent 

 that " positive work" which Cuvier held in such high esteem. 



More catching popular essays occupy the thoughts of the passing generations, but 

 these will vanish along with them, while your fruits of close and long-continued ob- 

 servation will endure, and carry down your honored name as an exemplar to the young 

 and genuine students of nature. As I have often thus thought of you and your works 

 80 am I happy in now expressing them, while we may be spared to interchange thought 

 and friendly regard on this fleeting scene of life. 

 Believe me, truly and sincerely yours, 



RICHARD OWEN. 



Vienna, June 28, L871. 



My Dear Sir : On the 10th of January I received through the Smithsonian Istitu- 

 tion and our ow^n Imperial Geological Institute your concluding index to the twelfth 

 volume of that grand work, "Observations on the Genus Unio.'' Pray, do kindly 

 accept of my most heartfelt thanks for that work, really of the most uncommon value, 

 the complete twelve volumes, which you kindly sent both to our Geological Institute 

 and to myself. 



Well may you exclaim now^ with old Horace, "Exegi monumentum," &c., and that 

 -will last so long as natural science shall be cultivated by mankind. The more it is 

 compared and studied the more appears your power of observation, your efforts in 

 pursuing your object, your steadiness and perseverance. During the long series of 

 years you did not tire sending me so many valuable contributions, by yourself, by Mr. 

 Henry Lea. by Mr. Carey Lea, for many of which I have been guilty of having ten- 

 dered too seldom, or even no acknowledgments at all. Pray, do now kindly accept of 

 a sum of tbem, along with the thanks for your last index. Well may you consider 

 this as a jubilee, fifty-three years having now gone by since you published your " Ac- 

 count of the Minerals at present known to exist in the vicinity of Philadelphia," iu 

 the Philadelphia Journal Academy Natural Sciences, I, 1817, pages 462-482, as I find 

 commemorated iu the "Catalogue of Scientific Papers, 1800 to 18C3," this memoir open- 

 ing the series of one hundred titles, images 898-902, in the third volume of that work 

 edited by the London Royal Society. 



From mineralogy, geology, natural philosophy, you first entered iuto the steady 

 study of your Unionidce and other allied species, not to leave them more till your beau 

 tiful monument was completed. 



I am not permitted to speak of advancing years to yon, who rather are my better, 

 but, indeed, since my serious illness in the winter of 18fi5 to 1866, and my retirement 

 from the ofSce of director-general of the Geological Institute, my state of health is 

 leather lower than I should wish. 



When again comparing the twelve volumes I also turned over again, with delight, 

 your old kind letters-, beginning with your stay iu our good city of Vienna in 1853, 

 along with your most honored family, Mrs. Lea and Miss Lea. I hope you all continue 

 well. Of our old friends of 1853, in Vienna, Franz von Haner, Fraunfeld, Swess, are 

 successfully at work, and well ; poor Partsch died in 1856, and a very great loss was 

 that of my particular, most excellent friend Homes, on the 4th of November, 1868. 



Please to remember me to all your family and friends. 

 Ever mo3t truly yours, 



W. HAIDINGER. 



