SURVEYS. 21 



or both. Check all measurements by chain or tape. Check 

 chains frequently by steel tape or level rod. 



Keep all instruments in proper condition and good adjust- 

 ment 



Always establish a substantial and permanent bench at the 

 Initial point of all surveys, and at short intervals along the 

 line. Use the sea-level datum, and if one has to be assumed, 

 ascertain its relation with the standard datum at the first 

 opportunity, and correct all elevations accordingly. 



All level notes must be checked at the end of each day's 

 work by adding the backsights and the foresights, and ascer- 

 taining the difference. 



MAPS, PROFILES AND RECORDS. 



Maps of located lines, made in the field, will be usually 

 drawn to a scale of 1 in. to 800 ft; in broken and difficult 

 localities, 1 in. to 400 ft. General maps to be sent to the 

 office of the Chief Engineer may be drawn to a scale of 1 in. 

 to 4,000 ft, etc. The maps will be made in conformity with 

 the standard specimen sheets furnished from the office of 

 Chief Engineer. 



Maps, plans and profiles are to be drawn with the top of 

 the paper to northward or westward, and the letters and fig- 

 ures are to be right side up toward the top or toward the left 

 hand side of the paper, and must otherwise conform with the 

 specimen profiles. 



Maps and profiles should give names of all rivers and 

 streams, names of owners or occupants of houses, ranches 

 or farms passed by the line, etc. Put on all the information 

 necessary to enable another person to fully identify any 

 locality. Be certain to note on profile all extreme high or 

 extreme low water marks, wherever found, even if only ap- 

 proximate. The meridian should be drawn on all maps, both 

 true and magnetic, when both are known. 



On each drawing of any kind, put name of engineer, initial 

 of draftsman, date, place, etc. On both ends of the outside 

 of the paper, give the title in full of the map, plan, sketch, or 

 profile. 



Tracings of maps and profiles of all lines run must be sent 



