Dr. Bowditch, President of the American Academy. ix 
What a contrast does this language form with that of the origi- 
nal compiler; who, in the very edition which contained the egre- 
gious and “criminal” blunder before mentioned, as well as his 
other “eight thousand” errors, has the assurance to announce to 
all “mariners,” that “he sells no sea-books, charts or instru- 
ments but such as may be depended on; consequently he ex- 
cludes all those old, inaccurate, and erroneous publications, the 
depending upon which has often proved fatal to shipping and 
seamen.” 
Notwithstanding this boasting language, however, as soon as Dr. 
Bowditch’s revision was known, the usual orders, which had before 
annually gone from America to England for thousands of copies of 
Moore’s Navigator, were stopped at once; the American work came 
into general use immediately in our own country, and was re- 
published in London.* 
Useful, however, as the “ Practical Navigator” has been, it is 
not thus particularly noticed, as a work to which Dr. Bowditch 
himself attached any importance in respect to his scientific reputa- 
tion, or in any other view than as a practical manual; the first 
excellence of which is, the greatest possible accuracy. From the 
period of its original publication, therefore, he spared no labor in 
making the most minute corrections and improvements. In the 
last edition, published in the autumn of 1837, the body of Tables 
has been increased, from thirty-three to fifty-six; some of them 
being entirely new, and others essentially improved or corrected. 
One or two of these improvements may be here referred to, as 
showing the extreme care used in the construction of the work. 
The tenth Table contains the distances at which any object is 
visible at sea, calculated by the rule given in Vince’s Astronomy 
* See Note C, at the end. 
2 
