IV. THOMAS KENNEDY. 



On a recent survey for extended contours at Barren Jack, 

 the proposed dam site on the Murrumbidgee River, the site 

 was contoured for 1,100 feet along the river to a height of 

 500 feet on one side and 410 feet on the other, the time 

 occupied on the survey being four days. The country has 

 an average slope of between 30° and 40°. On the last day 

 the tacheometer notes were reduced in the field and survey 

 was found to close before leaving for iiead quarters where 

 the plans were plotted. 



The advantage of knowing the reduced level and distance 

 is of great assistance in locating railways or contours. In 

 fact it is almost impossible to locate a long ruling grade 

 for a proposed railway without chaining and levelling the 

 traverse in the ordinary way. This especially applies to 

 rough and heavily timbered country. With an assistant to 

 book and check the reduction of notes there was found to 

 be in) delay in the field work, and with sufficient field hands 

 it would be possible in one day to traverse level and cross 

 level about two miles of preliminary railway survey in 

 ordinary open rolling country — as much as one and a quarter 

 miles was so surveyed in one day, but the country was rough 

 and heavily timbered, the time was mostly taken up in 

 clearing the traverse lines. When the work has to be done 

 without an assistant, it is better to have the table of 

 tangents on a separate sheet, preferably mounted on a stiff 

 card about the size of a page of the level book, so that the 

 angles can be read off without having to refer to another 

 book. 



The accuracy of the work is quite close enough for pre- 

 liminary surveys for railways or contouring areas of land. 

 As an example of the comparative results, a table is shewn 

 with the different results between the level staff and chain 

 and the tacheometer over about one mile of rough country. 

 The difference in distance is only five links, and of level 



