Attack by Filling 117 



may become saturated. If there are but a few 

 springs or sources of water, the fill can be kept 

 dry by making small ditches care for the water. 

 It is more economical and satisfactory to treat 

 fiat ditches than to attempt to oil wet grass- 

 covered areas. In the latter case, as the work is 

 performed by laborers who are fatigued by carry- 

 ing loads of oil in mud and water all day long, we 

 cannot count on their vigilance to ensure the entire 

 surface of every small body of water covered by 

 grass being completely covered by oil. Consequent- 

 ly it is essential to use large quantities of oil and 

 thoroughly saturate all of the wet land. The area 

 of the ditch as compared with the area of the wet 

 land to be filled will indicate the relative cost 

 of oiling each. Small areas are filled by pick, 

 shovel, and wheelbarrows. For larger areas 

 where suitable material is near, drag scrapers 

 or wheel scrapers drawn by horses are used. 



On the Isthmus much excavated material was 

 available and many acres were filled by dump 

 cars and Lidgerwood cars from which the mate- 

 rial was removed by a plow drawn by a steel 

 rope. On some of the heavy or deep fills made 

 by dump cars the soft land at the toe of the new 

 fills was sometimes thrust up by the weight of the 

 fill or rolled up in front of it. In making fills of 



