420 SCBVEY OF THE COAST OF THE UNITED STATES. 



INDEX TO NO. XIL 



Circular Letter from Secretary of the Treasury, - - 232 



Letter from F. R. Hassler to Mr. Gallatin, - - - 234 

 Plan for putting into operation the Survey of the Coast of the United 



States, -------- 241 



A Catalogue of the Instruments and Books collected for the Survey 



of the Coast, - - - - - - - 24& 



Comparison of the French and English Standard Measures of Length, 



and Regulation of the Bars for the Base Line Apparatus, - - 250 



Description of the Apparatus for measuring Base Lines, - - 273 



Description of the Two Feet Theodolite, ... - 287 



Methods of observing with the Two Feet Theodolite, - - 294 



On the Signals, and the System of Wires in the Telescope, - - 308 



Additions made to the Repeating Circle with Two Telescopes, - 315 



On some Adjustments of the Repeating Circle, - - - 320 

 Methods of observing a Series of Vertical Angles with the Repeating 



Circle, -------- 322 



Peculiar Method of observing Time with the Repeating Circle, ^ 326 



Description of the Repeating Theodolite of One Foot diameter, 328 



Method of observing Horizontal Angles with the Repeating Theodolite, 336 



Method of observing Vertical Angles with the Repeating Theodolite, 338 



Description of the Repeating Circle of Reflection, - - - 341 



Method of observing with the Repeating Reflecting Circle, - 345 



Description of the Plane Table, and the Alhidade to the same, 348 



Description of Magnetic Needles, ----- 354 



Peculiarities of the Five Feet Transit Instruments destined for the 



Observatories, - --,. . . , - 357- 



On the Astronomical Clocks intended for the Observatories, - 359 



Plan of an Observatory proposed to be built at Washingion, - 3G5 

 Promiscuous Remarks upon the Principles of Construction, the Choice 



and Trial of Instruments, ------ 371 



On the Mechanical Organisation of a Large Survey, and the Particular 



Application to the Survey of the Coast, - - - 385 



Exemplars of the Day Book and Journal of Results, - - - 409 



