LETTER OF TRANSMITTAL 
Department of the Interior, 
United States Geological Survey, 
W((sJdngton, D. CI, April M, 190 Ji. 
Sir: I have the honor to transmit herewith, in form for publication, 
the second edition (witli corrections and additions) of certain geo- 
graphic tables and formulas pertaining- to the work of the topographic 
branch of this Survey. As stated in the letter of transmittal of the 
first edition, published as Bulletin 214, the endeavor has been to bring 
together all tables and fornmlas used by the topographer in the field 
and office, and it is believed that their publication will be useful not 
only to the topographic corps but to others engaged in similar lines of 
work. The material has been drawn from various sources, some of it 
having been prepared from time to time by various members of the 
Geological Survey and the remaining portions having been taken 
principally from publications of the United States Coast and Geodetic 
Survey and the Smithsonian Institution. 
The matter has been revised by Mr. E. M. Douglas and Mr. H. L. 
Baldwin, jr. 
Ver}^ respectfully, 
S. S. Gannett, 
Geographer hi Charge 
Section of Triangulation and Comjmtmg. 
Hon. Charles D. Walcott, 
Director United States Geological Survey. 
7 
