54 NOTE. 



-t of the press-work of ordinary lithographic work, exclusive of the expenses "f the draw- 

 ings on st.'iic By judicious management of original drawings, it will doubtless be possible here- 

 after to reproduce the sketches of an investigation, and subsequent observers will he better able 



to judge of what has actually been seen, ami m>t of what h:i^ been added by the pencil of the 

 artist who copies the original drawings 



As far as my experience has gone, I have found it less troublesome, less expensive, and far 

 more accurate, to employ the photographic processes, although they required an occasional visit 

 to New York and Philadelphia, than to superintend, in the Museum building itself, the execution 

 of the lithographic plates issued at the same time. < >n account of the time required, not to speak 

 of the expense, to complete a large number of plates, cither as engravings or lithographs, it 

 would have been utterly impossible to issue so great a number of plates within the peri. id re- 

 quired for the permanent photographs. 



I cannot close without thanking Messrs. A. Sonrel, John Carbutt, E. Bierstadt, and A. Edwards 

 for the interest they have shown in the success of the illustrations, during the progress of the 

 work. 



ALEXANDER AGASSIZ. 



Cambridge, February, 1874. 



