39 



unsatisfactory on the heavy types of land, both in the rainy and dry 

 ijeasons. They tend to mire down when the land is wet and are more or 

 less injured by running over the irregular surface of the land when dry, 

 under both of which conditions they fail to develop enough power to 

 propel themselves and draw the plows through the soil. Even when the 

 land was in good condition for plowing, if there was considerable vegeta- 

 tion on it or heavy dews prevailed, difficulty was experienced on account 

 of the choking of the plows and the accumulation of sticky soil on the 

 wheels with consequent slipping. The use of mud hooks results in a 



Fig. 7. — Bureau of Agriculture two-way disk gang plow with middle breaker. 



distinct loss of power in both wet and dry land and after the wheels have 

 become thoroughly gummed with the sticky dirt the mud hooks are 

 almost useless in preventing slipping. These engines have also proven 

 extremely difficult to move about the Islands on account of the necessity 

 for using water transportation between ports and passing over bad roads 

 and flimsy wooden or bamboo bridges, 



A two-cylinder petroleum engine, starting on gasoline and weighing 

 only about 9 tons, has been tried with a little better success. It is also 

 much more convenient on account of not requiring water and using a 



