136 



that almost any of the boundaries may serve as a base-line; I always 

 use one surveyed by Government and clearly marked with stones s 

 whatever may happen, as long as the base-line is fixed the whole 

 co-ordinate system may be reconstructed on it. 



In the attached plan I would chose X-Y as my base-line; as soon 

 as it has been properly cleared, pegs are put in along it correctly 10 

 chains apart, starting at X. On the point marking the last 6th length 

 of whole 10 chains the right angle-line, Y-Z is put in, if possible with 

 a theodolite; prismatic compasses are sometimes unreliable and as 

 this is the one line which cannot be checked it is as well to take 

 some trouble in getting it accurately at right angles to base-line. 



On this second line lengths of 10 chains are again marked and the 

 rest is detail work which cannot only be easily done by any man 



conversant with , 



compass I 



to either base-line or right-angle-line, or to the last paralled line to 

 these two which has been checked previously. 



The main difference between these two important lines is that 

 from the base-lines all shots will have to go in one direction whereas 

 from right-angle-line rentices start towards right and left. 



In laying out a block of jungle it is of course essential that the 

 crossing points of any two rentices indicating, as they do, one of the 

 four corners of any io-acre blocks, should be well marked. Pegs 

 and posts, however big, are not safe as they can entirely disappear 

 in telling and burning. I found a strong peg rammed flush with 

 the ground and covered with 3-6 big stones to answer well, 

 contractors having been asked not to fell trees across the rentices. 

 In land where it is hard to get any stone I am having a strong peg 

 put in the bottom of a 3 ft. x 3 ft. X 1 ft. hole. In flat land which 

 nas to be thoroughly drained I fancy that drains could advantageousl) 

 be made to take the place of dividing rentices. 



It is, of course, by no means necessary to lay out the whole of a big 

 estate in this way; in the attached sketch for instance, according 

 «mch it may be proposed to open a 100-acre field, all that » 

 required ,s the "base line" and part of the « right-angle-hne . 

 further 20 chains each between A, B, C D, E and F fields and 50 

 chains each between fields , and 2/ and 2 and 3. 

 allover^T: 61 "' be al «'ays useful to complete the whole system 

 all over the Estate to begin with as opening work can then alwaf 

 be undertaken at the shortest noticed and should at any time road, 

 wo ksTw^' haVC t0 be instructed through part of the jungle of 



^i n lS^S^ from thefirst cleanng ' the 



It is of course 

 Xnea^ Vf^'^^ng^th^le two maTnlin" 

 all measures taken should be entered on plan, all corner pegs mar^ 

 and complete squares made clearly distinguishable, further that 

 note and distance should be taken of every ftream, hill, ridge, pa* 



