CANE SUGAR. 



enclose the piece of land which is to be put into cultivation ; more frequently, 

 however, a double section is formed with two sideline dams and a back dam as 

 empoldering dams, a navigation dam running in the centre of the two half 

 sections, and serving equally for both. In Figs. 38 and 39 are given plans of 

 the arrangements of field customary in British Guiana ; a is the navigation 

 dam formed by the excavation of the navigation trench b ; the navigation 

 trench continues up to the factory, and is used for the transport of cane and 

 produce, and also to supply water for irrigation and other purposes. This 

 canal is connected with a river, creek or lake ; or where this is impossible, a 

 large canal capable of supplying a batch of estates carries water from a river. 

 Many estates have pumping stations situated on a river, so that they^are nearly 

 independent of drought; on other estates a 'drought may cause the level of 



FIG. 37. 



water in the river or creek to fall so much that it is necessary to take sea 

 water into the trenches. At e are shown cross canals communicating with 

 the navigation trench, and terminating about 20 to 25 feet from the sideline or 

 drainage canal c ; the cross canals are used for the purpose of bringing the 

 punts or barges used for transport within access of the canes ; the main 

 drainage canal runs out to the sea or river. Drainage is either forced or 

 natural ; in the former case centrifugal or sluice wheel pumps are employed, 

 the first named being by far the most economical ; in the latter case the side- 

 line discharges at low tide into the sea or river. Between the cross canals 

 lie the fields, usually of area 10 to 20 acres, the distance from cross canal to 

 cross canal being about 500 feet. In Demerara two kinds of fields are 



110 



