138 LOUIS AGASSIZ 



even then I should like to have a hand 

 in arranging the party, as I feel that 

 there never was, and is not likely soon 

 again to be, such an opportunity for 

 promoting the cause of science generally 

 and that of natural history in particu- 

 lar. " 



The voyage lasted from December, 

 1871, to August, 1872. Mrs. Agassiz ac- 

 companied her husband again, acting as 

 secretary ; and a joint journal, partly per- 

 sonal, partly scientific, was kept by the 

 two, but was never completely published. 

 Long and interesting letters reporting 

 progress to Professor Peirce were given 

 to the public ; but more interesting than 

 any of these was the letter Agassiz wrote 

 just before sailing, in which he desired 

 to leave on record his expectations con- 

 cerning the fauna of the deep sea. It 

 was his opinion that the conditions of 

 pressure, temperature, darkness, etc., 

 which prevail at great depths would be 

 accompanied by a fauna resembling that 



