no 



Louis Agassiz. 



estimate of the growth of corals was very low. In 

 a paper and afterwards in his Methods of Study 

 he says in substance that a brick placed under water 

 in 1850 by Captain Woodbury was taken up in 1858 

 and found to have a crust of coral upon it a little 

 more than half an inch in thickness. This is evidently 

 a mistake, as Captain Woodbury was not ordered to 

 Tortugas until 1857. The brick referred to is 

 probably one sent to Prof. Agassiz by Dr. Holder. 

 The piece of brick when first found had a small head 

 of Meafidrina convexa upon the side. Dr. Holder 

 watched it a year, keeping it in the aquarium under 

 what might be considered unfavourable circum- 

 stances for its rapid growth, and found that in twelve 

 months it doubled its diameter, or from one inch 

 it had increased to two, the growth being one inch 

 in a year instead of half an inch in eight years ; or 

 in another case mentioned by Prof. Agassiz, half an 

 inch in ten years. Dr. Holder thus established the 

 fact that the growth of this genus of corals was 

 much more rapid than was generally supposed. A 

 cut of the coral is figured in Holder's Elements of 

 Zoology, 



The new museum, while it occupied much of 

 Agassiz's time and resources, did not prevent him 

 from devoting attention to various new fields. He 

 was continually bringing out some new work, and 

 his Contributions'* are monuments to his industry 

 in these years. Humboldt wrote regarding the lat- 

 ter: . . . I hear that by some untoward circum- 

 stances, no doubt accidental, you have never received, 

 my dear Agassiz, the letter expressing the pleasure 



