SUMMER MEETING. 71 



plumbbob or any metal weight. Slightly sharpen the lower end of the 

 upright or lath so it can be stuck into the ground. This is the level, 

 and will cost, in material, from 5 to 50 cents. 



Before attempting to level with it, it must be adjusted. Stick the 

 sharpened end in the ground and sight along the top of the triangle to 

 a point on a line with it : i. e., with the top. This point should be from 

 50 to 100 feet distant. Mark the point. Now lift the triangle off of 

 the spindle and change sides, thus bringing the opposite side next to 

 you. Do not let the staff or upright be moved. Now sight along the 

 top again. If the same point is in the line of sight as at first, the in- 

 strument is in adjustment. Should the last sight indicate a point below 

 the mark, bend the lower end of the loop that suspends the weight 

 toward you ; if above the mark, from you. The error will thus be 

 corrected. If, after several changings or turnings of the triangle, the 

 same point is indicated as being in line with the top of the triangle, the 

 level is adjusted and "ready for business." 



In using the level, remember to not move the staff until you have 

 taken both a back sight and a front sight. You start with a back 

 sight. Do not attempt to sight more than 200 feet with this level. 

 Take a barn batten and make you a level-rod. Let your rodman set 

 the rod at a point, say A. Let us assume that the elevation of A is 

 700 feet. Set the level and back-sight at the rod. The reading on the 

 rod is, say, 4 feet 3 inches. Do not move the level. Let the rodman 

 pass around you and set up at the point B. You walk around to the 

 other side of the level and read the rod. Suppose the reading is 7 

 feet 10 inches. The diti'erence between these readings, 3 feet 7 inches, 

 is the difference in elevation of the points A and B. Now, the higher 

 the reading on the rod, the lower the point. As the reading at B was 

 3 feet 7 inches higher than at A, B is that much lower than is A. 

 Three feet 7 inches substracted from 700 feet leave 696 feet 5 inches. 

 This then is the elevation of B. As you proceed, write in your field- 

 notes the location, manner of designation and elegation of each point. 

 Let your rodman hold his point, not moving the bottom of the rod,, 

 while you walk around him to any convenient point and set the level 

 again. Take your reading as a back-sight. Suppose it is 2 feet 5 

 inches. Now the rodman sets up at a third point, C. Without moving 

 the instrument, you read Jhe rod, and the reading is, say 8 feet. The 

 difference between B and C is, then, 5 feet 7 inches. The last reading 

 was the higher. Then C is 5 feet 7 inches lower than is B. The ele- 

 vation of C is, then, 690 feet 10 inches. So proceed. 



